0000950170-24-095082 | 10-Q | XBRL Viewer | Taysha Gene Therapies INC

Print Document

Income Taxes - Additional Information (Details)	6 Months Ended
Income Taxes - Additional Information (Details)	Jun. 30, 2024 USD ($)
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 0

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Leases (Tables)

6 Months Ended

Jun. 30, 2024

Leases [Abstract]

Schedule of Lease Cost

The following table summarizes the lease costs recognized under ASC 842 and other information pertaining to the Company’s operating leases for the three and six months ended June 30, 2024 and 2023 (in thousands):


	Three Months Ended June 30,				For the Six Months Ended June 30,
	2024		2023		2024		2023
Operating lease cost	$	675	$	708	$	1,321	$	1,360
Variable lease cost		198		243		396		486
Total lease cost	$	873	$	951	$	1,717	$	1,846

Schedule of Supplemental Information Related to Remaining Lease Term and Discount Rate

Supplemental information related to the remaining lease term and discount rate are as follows:


	June 30, 2024			December 31, 2023
Weighted average remaining lease term (in years) – Finance leases		2.38			2.88
Weighted average remaining lease term (in years) – Operating leases		10.36			10.75

Weighted average discount rate – Finance leases		10.53	%		10.52	%
Weighted average discount rate – Operating leases		7.82	%		7.80	%

Schedule of Supplemental Cash Flow Information Related to Operating Leases

Supplemental cash flow information related to the Company’s operating leases are as follows (in thousands):


	For the Six Months Ended June 30,
	2024		2023
Operating cash flows for operating leases	$	1,391	$	1,631

Schedule of Future Minimum Commitments Under Company's Operating and Finance Leases

As of June 30, 2024, future minimum commitments under ASC 842 under the Company’s operating and finance leases were as follows (in thousands):


Year Ending December 31,	Operating			Finance
2024	$	1,423		$	227
2025		2,910			454
2026		2,485			399
2027		2,577			—
2028		2,673			—
Thereafter		17,045			—
Total lease payments		29,113			1,080
Less: imputed interest		(9,596	)		(129	)
Total lease liabilities	$	19,517		$	951
Lease liabilities, current		1,383			371
Lease liabilities, non-current		18,134			580
Total lease liabilities	$	19,517		$	951

Fair Value Measurements

6 Months Ended

Jun. 30, 2024

Fair Value Disclosures [Abstract]

Fair Value Measurements

Note 3—Fair Value Measurements

The Company’s financial instruments that are measured at fair value on a recurring basis consist of money market funds, the Trinity Term Loans, a success fee derivative liability and certain of the Company’s warrant liabilities.

The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis and indicate the level of the fair value hierarchy used to determine such fair values (in thousands):


	June 30, 2024
	Total		Level 1		Level 2		Level 3
Assets:
Cash equivalents – money market funds	$	172,103	$	172,103	$	—	$	—
Total assets	$	172,103	$	172,103	$	—	$	—
Liabilities:
Trinity Term Loans	$	37,835	$	—	$	—	$	37,835
Success Fee Derivative liability		800		—		—		800
SSI Warrant liability		596		—		—		596
Total liabilities	$	39,231	$	—	$	—	$	39,231


	December 31, 2023
	Total		Level 1		Level 2		Level 3
Assets:
Cash equivalents – money market funds	$	142,425	$	142,425	$	—	$	—
Total assets	$	142,425	$	142,425	$	—	$	—
Liabilities:
Trinity Term Loans	$	40,508	$	—	$	—	$	40,508
Success Fee Derivative liability		800		—		—		800
SSI Warrant liability		454		—		—		454
Total liabilities	$	41,762	$	—	$	—	$	41,762

The Company classifies its money market funds, which are valued based on quoted market prices in an active market with no valuation adjustment, as Level 1 assets within the fair value hierarchy.

The Company’s Trinity Term Loans and Success Fee liability are classified as Level 3 measurements under the fair value hierarchy as the fair values were determined based on significant inputs not observable in the market. The fair values were determined utilizing a probability-weighted income approach, including variables for the timing of a success event and other probability estimates. See Note 7 for additional information on the Trinity Term Loans and Success Fee.

The Company’s SSI Warrant liability is classified as Level 3 measurements under the fair value hierarchy as the fair values were determined based on significant inputs not observable in the market. The fair values were determined using the Black-Scholes-Merton option pricing model to determine the fair value of the SSI Warrants (as defined below). See Note 10 for additional information on the SSI Warrants.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Warrants - Schedule Of Assumptions Used To Estimate Fair Value Of Warrants (Details)	Jun. 30, 2024 USD ($) yr	Apr. 05, 2023 USD ($) yr
Risk-free interest rate
Class of Warrant or Right [Line Items]
Warrants, measurement input	4.43	3.46
Expected term (in years)
Class of Warrant or Right [Line Items]
Warrants, measurement input \| yr	4.4	5.2
Expected volatility
Class of Warrant or Right [Line Items]
Warrants, measurement input	88	81
Market value of common stock (per share)
Class of Warrant or Right [Line Items]
Warrants, measurement input \| $	2.24	0.71

Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2024	Aug. 12, 2024
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q2
Trading Symbol	TSHA
Entity Registrant Name	Taysha Gene Therapies, Inc.
Entity Central Index Key	0001806310
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity File Number	001-39536
Entity Tax Identification Number	84-3199512
Entity Address, Address Line One	3000 Pegasus Park Drive
Entity Address, Address Line Two	Ste 1430
Entity Address, City or Town	Dallas
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	75247
City Area Code	214
Local Phone Number	612-0000
Entity Common Stock, Shares Outstanding		204,943,306
Title of 12(b) Security	Common stock, par value $0.00001 per share
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Entity Interactive Data Current	Yes
Document Quarterly Report	true
Document Transition Report	false

Leases - Schedule of Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Lease, Cost [Abstract]
Operating lease cost	$ 675	$ 708	$ 1,321	$ 1,360
Variable lease cost	198	243	396	486
Total lease cost	$ 873	$ 951	$ 1,717	$ 1,846

Warrants - Schedule of Fair Value Method to Allocate Net Proceeds Received from Sale of Common Stock and Pre-funded Warrants (Details)	Jun. 30, 2024 USD ($)
Class of Warrant or Right [Line Items]
Common stock and warrants fair value disclosure	$ 149,953
PIPE Shares
Class of Warrant or Right [Line Items]
Common stock and warrants fair value disclosure	110,127
2023 Pre-Funded Warrants
Class of Warrant or Right [Line Items]
Common stock and warrants fair value disclosure	$ 39,826

Strategic Reprioritization - Additional Information (Details) - Exit and Disposal Activities - USD ($) $ in Millions	3 Months Ended	4 Months Ended
	Mar. 31, 2022	Mar. 31, 2023
Restructuring Cost and Reserve [Line Items]
Percentage of headcount reduced	35.00%
Severance and termination-related costs	$ 2.6	$ 2.7

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References + Details

Leases - Additional Information (Details) $ in Thousands				6 Months Ended
Leases - Additional Information (Details) $ in Thousands	Dec. 14, 2021 USD ($) ft²	Jan. 11, 2021 ft²	Dec. 17, 2020 ft²	Jun. 30, 2024 USD ($)	Dec. 31, 2023 USD ($)
Lessee, Lease, Description [Line Items]
Future minimum remianing lease payments				$ 29,113
Restricted cash, current				449	$ 449
Restricted cash, noncurrent				$ 2,151	2,151
Durham Lease
Lessee, Lease, Description [Line Items]
Number of operating lease landlord square feet manufacturing facility \| ft²			187,500
Operating lease commencement date			Apr. 01, 2021
Operating lease term of contract			15 years 6 months
Lease, option to extend description				Company has two options to extend the term of the Durham Lease, each for a period of an additional five years.
Operating lease extend term of contract			5 years
Amount required to place in escrow account				$ 2,600
Restricted cash, current				500	500
Restricted cash, noncurrent				$ 2,100	$ 2,100
Pegasus Park L L C \| Dallas Lease
Lessee, Lease, Description [Line Items]
Number of operating lease landlord square feet manufacturing facility \| ft²		15,000
Operating lease commencement date		May 27, 2021
Operating lease term of contract		10 years
Lease, option to extend description		Company has an option to extend the term of the Dallas Lease for one additional period of five years.
Pegasus Park L L C \| Dallas Lease Amendment
Lessee, Lease, Description [Line Items]
Number of operating lease landlord square feet manufacturing facility \| ft²	18,000
Operating lease term of contract	10 years
Future minimum remianing lease payments	$ 6,000
Pegasus Park L L C \| Dallas Lease Amendment \| Minimum
Lessee, Lease, Description [Line Items]
Maximum construction allowance provided by landlord per rentable square foot \| ft²	40

Retirement Plan - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Defined Benefit Plan Disclosure [Line Items]
Contribution to retirement savings plan	$ 0.1	$ 0.1	$ 0.3	$ 0.2

Leases

6 Months Ended

Jun. 30, 2024

Leases [Abstract]

Leases

Note 5— Leases

The Company leases certain office, laboratory, and manufacturing space.

Dallas Lease

On January 11, 2021, the Company entered into a lease agreement (the “Dallas Lease”) with Pegasus Park, LLC, a Delaware limited liability company (the “Dallas Landlord”), pursuant to which the Company leases approximately 15,000 square feet of office space at 3000 Pegasus Park Drive, Dallas, Texas 75247 (the “Office Space”).

The Dallas Lease commenced on May 27, 2021, and has a term of approximately ten years. The Company has an option to extend the term of the Dallas Lease for one additional period of five years.

The Dallas Landlord has the right to terminate the Dallas Lease, or the Company’s right to possess the Office Space without terminating the Dallas Lease, upon specified events of default, including the Company’s failure to pay rent in a timely manner and upon the occurrence of certain events of insolvency with respect to the Company.

Dallas Lease Expansion

On December 14, 2021, the Company amended the Dallas Lease (the “Dallas Lease Amendment”) with the Dallas Landlord, pursuant to which the Company leases approximately 18,000 square feet of office space adjacent to the Office Space at 3000 Pegasus Park Drive, Dallas, Texas 75247 (the “Expansion Premises”).

The Dallas Lease Amendment commenced on July 1, 2022, and has a term of approximately ten years.

The Company is obligated to pay operating costs and utilities applicable to the Expansion Premises. Total future minimum lease payments under the Dallas Lease Amendment over the initial 10 year term are approximately $6.0 million. The Company is responsible for costs of constructing interior improvements within the Expansion Premises that exceed a $40.00 per rentable square foot construction allowance provided by the Dallas Landlord.

The Company has a right of first refusal with respect to certain additional office space on the 15th floor at 3000 Pegasus Park Drive, Dallas, Texas 75247 before the Dallas Landlord accepts any offer for such space.

Durham Lease

On December 17, 2020, the Company entered into a lease agreement (the “Durham Lease”) with Patriot Park Partners II, LLC, a Delaware limited liability company (the “Durham Landlord”), pursuant to which the Company agreed to lease approximately 187,500 square feet of a manufacturing facility located at 5 National Way, Durham, North Carolina (the “Facility”). The Durham Lease commenced on April 1, 2021 and is expected to have a term of approximately fifteen years and six months. The Company has two options to extend the term of the Durham Lease, each for a period of an additional five years.

The Company was not required to provide a security deposit in connection with its entry into the Durham Lease. The Company was responsible for constructing interior improvements within the Facility. The Company was required to place $2.6 million in an escrow account which was to be released when the improvements were substantially complete. In December 2023, the Company entered into an agreement with the landlord whereby the Company agreed to remove specified leasehold improvements which will be funded by the escrowed funds. The escrow funds are recorded as restricted cash on the condensed consolidated balance sheets as of June 30, 2024 and December 31, 2023 with $0.5 million recorded in current assets and $2.1 million in noncurrent assets. The Durham Landlord has the right to terminate the Durham Lease upon specified events of default, including the Company’s failure to pay rent in a timely manner and upon the occurrence of certain events of insolvency with respect to the Company.

Summary of all lease costs recognized under ASC 842


	Three Months Ended June 30,				For the Six Months Ended June 30,
	2024		2023		2024		2023
Operating lease cost	$	675	$	708	$	1,321	$	1,360
Variable lease cost		198		243		396		486
Total lease cost	$	873	$	951	$	1,717	$	1,846

Supplemental information related to the remaining lease term and discount rate are as follows:


	June 30, 2024			December 31, 2023
Weighted average remaining lease term (in years) – Finance leases		2.38			2.88
Weighted average remaining lease term (in years) – Operating leases		10.36			10.75

Weighted average discount rate – Finance leases		10.53	%		10.52	%
Weighted average discount rate – Operating leases		7.82	%		7.80	%

Supplemental cash flow information related to the Company’s operating leases are as follows (in thousands):


	For the Six Months Ended June 30,
	2024		2023
Operating cash flows for operating leases	$	1,391	$	1,631

As of June 30, 2024, future minimum commitments under ASC 842 under the Company’s operating and finance leases were as follows (in thousands):


Year Ending December 31,	Operating			Finance
2024	$	1,423		$	227
2025		2,910			454
2026		2,485			399
2027		2,577			—
2028		2,673			—
Thereafter		17,045			—
Total lease payments		29,113			1,080
Less: imputed interest		(9,596	)		(129	)
Total lease liabilities	$	19,517		$	951
Lease liabilities, current		1,383			371
Lease liabilities, non-current		18,134			580
Total lease liabilities	$	19,517		$	951

Research, Collaboration and License Agreements

6 Months Ended

Jun. 30, 2024

Research Collaboration And License Agreements [Abstract]

Research, Collaboration and License Agreements

Note 8—Research, Collaboration and License Agreements

UT Southwestern Agreement

On November 19, 2019, the Company entered into a research, collaboration and license agreement (“UT Southwestern Agreement”) with the Board of Regents of the University of Texas System on behalf of The University of Texas Southwestern Medical Center (“UT Southwestern”). Under the UT Southwestern Agreement, UT Southwestern is primarily responsible for preclinical development activities with respect to licensed products for use in certain specified indications (up to investigational new drug application-enabling studies), and the Company is responsible for all subsequent clinical development and commercialization activities with respect to the licensed products. UT Southwestern will conduct such preclinical activities for a two-year period under mutually agreed upon sponsored research agreements that were entered into beginning in April 2020. During the initial research phase, the Company has the right to expand the scope of specified indications under the UT Southwestern Agreement.

In connection with the UT Southwestern Agreement, the Company obtained an exclusive, worldwide, royalty-free license under certain patent rights of UT Southwestern and a non-exclusive, worldwide, royalty-free license under certain know-how of UT Southwestern, in each case to make, have made, use, sell, offer for sale and import licensed products for use in certain specified indications. Additionally, the Company obtained a non-exclusive, worldwide, royalty-free license under certain patents and know-how of UT Southwestern for use in all human uses, with a right of first refusal to obtain an exclusive license under certain of such patent rights and an option to negotiate an exclusive license under other of such patent rights. The Company is required to use commercially reasonable efforts to develop, obtain regulatory approval for, and commercialize at least one licensed product.

On April 2, 2020, the Company amended the UT Southwestern Agreement to include the addition of another licensed product and certain indications, and a right of first refusal to the Company over certain patient dosing patents. No additional consideration was transferred in connection with this amendment. In March 2022, the Company and UT Southwestern mutually agreed to revise the payment schedules and current performance expectations of the current sponsored research agreements under the UT Southwestern Agreement and defer payments by fifteen months. In December 2023, the Company and UT Southwestern mutually agreed to terminate specific sponsored research agreements.

The UT Southwestern Agreement expires on a country-by-country and licensed product-by-licensed product basis upon the expiration of the last valid claim of a licensed patent in such country for such licensed product. After the initial research term, the Company may terminate the agreement, on an indication-by-indication and licensed product-by-licensed product basis, at any time upon specified written notice to UT Southwestern. Either party may terminate the agreement upon an uncured material breach of the

agreement or insolvency of the other party. In December 2023, the Company transferred rights to specific indications back to UT Southwestern.

In November 2019, as partial consideration for the license rights granted under the UT Southwestern Agreement, the Company issued 2,179,000 shares of its common stock, or 20% of its then outstanding fully-diluted common stock, to UT Southwestern. The Company does not have any future milestone or royalty obligations to UT Southwestern under the UT Southwestern Agreement other than costs related to maintenance of patents.

Queen’s Agreement

On February 21, 2020, the Company entered into a license agreement (the “Queen’s Agreement”) with Queen’s University at Kingston (“Queen’s”) to obtain the exclusive perpetual, royalty-bearing license, with the right to sublicense through multiple tiers, under certain patent rights and know-how of Queen’s, including certain improvements to such patent rights and know-how, to develop products in any field which use one or more valid claims of the patents licensed under the Queen’s Agreement (the “Licensed Patents”), or the technology, information and intellectual property related to the patents licensed under the Queen’s Agreement (together with the Licensed Patents, the “Licensed Products”), and to make, have made, use, sell, offer for sale, import and export Licensed Products and otherwise exploit such patents and know-how for use in certain specified indications. In exchange for the rights granted to the Company, the Company made a cash payment of $3.0 million in April 2020 which was recorded within research and development expenses in the consolidated statements of operations since the acquired license does not have an alternative future use. The Company is obligated to make aggregate cash payments of up to $10.0 million upon the completion of a combination of regulatory milestones and up to $10.0 million upon the completion of a combination of commercial milestones. In further consideration of the rights granted, beginning with the Company’s first commercial sale of the Licensed Products, the Company will also pay an annual earned royalty in the low single digits on net sales of Licensed Products, subject to certain customary reductions, and a percentage of non-royalty sublicensing revenue ranging in the low double digits. Royalties are payable, on a Licensed Products-by-Licensed Products and a country-by-country basis, until expiration of the last valid claim of a Licensed Patent covering such Licensed Products in such country and the expiration of any regulatory exclusivity for such Licensed Products in such country.

In January 2024, the Company transferred rights back to Queen’s for the Licensed Patents. No additional milestone payments were made in connection with the Queen’s Agreement during the six months ended June 30, 2024.

Abeona CLN1 Agreements

In August 2020, the Company entered into license and inventory purchase agreements with Abeona Therapeutics Inc. (“Abeona”) for worldwide exclusive rights to certain intellectual property rights and know-how relating to the research, development and manufacture of ABO-202, an AAV-based gene therapy for CLN1 disease (also known as infantile Batten disease). Under the terms of the agreements, the Company made initial cash payments to Abeona of $3.0 million for the license fee and $4.0 million for purchase of clinical materials and reimbursement for previously incurred development costs in October 2020. In exchange for the license rights, the Company recorded an aggregate of $7.0 million within research and development expenses in the consolidated statements of operations for the year ended December 31, 2020 since the acquired license or acquired inventory do not have an alternative future use. The Company is obligated to make up to $26.0 million in regulatory-related milestones and up to $30.0 million in sales-related milestones per licensed CLN1 product. The Company will also pay an annual earned royalty in the high single digits on net sales of any licensed CLN1 products. The license agreement expires on a country-by-country and licensed product-by-licensed product basis upon the expiration of the last royalty term of a licensed product. Either party may terminate the agreement upon an uncured material breach of the agreement or insolvency of the other party. The Company may terminate the license agreement for convenience upon specified prior written notice to Abeona.

In December 2021, a regulatory milestone was triggered in connection with this agreement and therefore the Company recorded $3.0 million within research and development expenses in the consolidated statements of operations for the year ended December 31, 2021. The milestone fee was paid in January 2022 and classified as an investing cash outflow in the condensed consolidated statements of cash flows. No additional milestone payments were triggered in connection with this agreement during the six months ended June 30, 2024.

Abeona Rett Agreement

On October 29, 2020, the Company entered into a license agreement (the “Abeona Rett Agreement”) with Abeona pursuant to which the Company obtained an exclusive, worldwide, royalty-bearing license, with the right to grant sublicenses under certain patents, know-how and materials originally developed by the University of North Carolina at Chapel Hill, the University of Edinburgh and Abeona to research, develop, manufacture, have manufactured, use, and commercialize licensed products for gene therapy and the use of related transgenes for Rett syndrome.

Subject to certain obligations of Abeona, the Company is required to use commercially reasonable efforts to develop at least one licensed product and commercialize at least one licensed product in the United States.

In connection with the Abeona Rett Agreement, the Company paid Abeona a one-time upfront license fee of $3.0 million which was recorded in research and development expenses in the consolidated statements of operations for the year ended December 31, 2020 since the acquired license does not have an alternative future use. The Company is obligated to pay Abeona up to $26.5 million in regulatory-related milestones and up to $30.0 million in sales-related milestones per licensed Rett product and high single-digit royalties on net sales of licensed Rett products. Royalties are payable on a licensed product-by-licensed product and country-by-country basis until the latest of the expiration or revocation or complete rejection of the last licensed patent covering such licensed product in the country where the licensed product is sold, the loss of market exclusivity in such country where the product is sold, or, if no licensed product exists in such country and no market exclusivity exists in such country, ten years from first commercial sale of such licensed product in such country.

The Abeona Rett Agreement expires on a country-by-country and licensed product-by-licensed product basis upon the expiration of the last royalty term of a licensed product. Either party may terminate the agreement upon an uncured material breach of the agreement or insolvency of the other party. The Company may terminate the agreement for convenience upon specified prior written notice to Abeona.

In March 2022, the Company’s clinical trial application, (“CTA”) filing for TSHA-102 for the treatment of Rett Syndrome was approved by Health Canada and therefore triggered a regulatory milestone payment in connection with this agreement. The Company recorded $1.0 million within research and development expenses and classified the payment as an investing cash outflow in the consolidated statements of cash flows. In May 2023, the Company dosed the first patient with TSHA-102 in the Phase 1/2 REVEAL trial evaluating the safety and preliminary efficacy of TSHA-102 in adult patients with Rett syndrome and therefore triggered a milestone payment in connection with the Abeona Rett Agreement. The Company recorded $3.5 million within research and development expenses in the condensed consolidated statements of operations for the year ended December 31, 2023. This milestone fee was paid in August 2023 and classified as an investing cash outflow in the consolidated statements of cash flows for the year ended December 31, 2023. No additional milestone payments were made or triggered in connection with this agreement during the six months ended June 30, 2024.

TSHA-120 for the treatment of GAN

In March 2021, the Company acquired the exclusive worldwide rights to a clinical-stage AAV9 gene therapy program (developed by the Company as TSHA-120) for the treatment of GAN pursuant to a license agreement (the “GAN License Agreement”) with Hannah’s Hope Fund for Giant Axonal Neuropathy, Inc. (“HHF”). In connection with the GAN License Agreement, the Company also obtained rights to collaborate with the National Institute of Neurological Disorders and Stroke (“NINDS”) on a clinical trial for TSHA-120, an intrathecally dosed AAV9 gene therapy for the treatment of GAN.

Under the terms of the GAN License Agreement, in exchange for granting the Company the exclusive worldwide rights to TSHA-120, HHF received an upfront payment of $5.5 million. No additional milestone payments were made or triggered in connection with the GAN License Agreement during the six months ended June 30, 2024. In January 2024, the Company initiated the return of the FDA Investigational New Drug application and transfer of the investigational clinical trial material for TSHA-120 in GAN to NINDS, enabling an opportunity for continued clinical evaluation of TSHA-120 in GAN after the Company discontinued development of TSHA-120 in GAN in September 2023. In January 2024, the Company gave notice of termination of the GAN License Agreement, and such termination became effective in July 2024 when all licensed rights under the GAN License Agreement reverted to HHF.

License Agreement for CLN7

In March 2022, the Company entered into a license agreement with UT Southwestern (the “CLN7 Agreement”) pursuant to which the Company obtained an exclusive worldwide, royalty-bearing license with right to grant sublicenses to develop, manufacture, use, and commercialize licensed products for gene therapy for CLN7, a form of Batten Disease. In connection with the CLN7 Agreement, the Company paid a one-time upfront license fee of $0.3 million. The Company recorded the upfront license fee in research and development expense in the condensed consolidated statements of operations since the acquired license does not have an alternative future use. The Company is obligated to pay UT Southwestern up to $7.7 million in regulatory-related milestones and up to $7.5 million in sales-related milestones, as well as a low, single-digit royalty on net sales upon commercialization of the product.

No additional milestone payments were made or triggered in connection with this agreement during the six months ended June 30, 2024.

Summary of Significant Accounting Policies

6 Months Ended

Jun. 30, 2024

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

Note 2—Summary of Significant Accounting Policies

Basis of Presentation

The unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States (“GAAP”) as determined by the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X and are consistent in all material respects with those included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023, filed with the Securities and Exchange Commission (“SEC”) on March 19, 2024 (the “2023 Annual Report”). In the opinion of management, the unaudited condensed consolidated financial statements reflect all adjustments, which include only normal recurring adjustments necessary for the fair statement of the balances and results for the periods presented. The condensed consolidated balance sheet as of December 31, 2023 is derived from audited financial statements, however, it does not include all of the information and footnotes required by GAAP for complete financial statements. These unaudited condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and related notes in the Company’s 2023 Annual Report.

Principles of Consolidation

The accompanying interim condensed consolidated financial statements include the accounts of Taysha and its wholly owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation.

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. The most significant estimates and assumptions in the Company’s financial statements relate to the determination of the fair value of the common stock prior to the initial public offering (“IPO”) (as an input into stock-based compensation), estimating manufacturing accruals and accrued or prepaid research and development expenses, the measurement of impairment of long-lived assets, the valuation of the Trinity Term Loans that are carried at fair value and the allocation of consideration received in connection with the Astellas Transactions (as defined below). These estimates and assumptions are based on current facts, historical experience and various other factors believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities and the recording of expenses that are not readily apparent from other sources. Actual results may differ materially from these estimates. To the extent there are material differences between the estimates and actual results, the Company’s future results of operations will be affected.

Significant Accounting Policies

There have been no changes in the Company’s significant accounting policies as disclosed in Note 2 to the audited consolidated financial statements included in the 2023 Annual Report.

Recently Adopted Accounting Pronouncements

There have been no significant changes in recently adopted accounting pronouncements from those disclosed in the section titled “Financial Statements and Supplementary Data” included in the 2023 Annual Report.

Recently Issued Accounting Pronouncements

In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting – Improvements to Reportable Segment Disclosures, to improve segment disclosure requirements under ASC 280, Segment Reporting, through enhancing disclosures about significant segment expenses. The guidance requires entities to provide significant segment expenses that are regularly provided to the chief operating decision maker and other segment expenses included in each reported measure of segment profitability. The ASU also enhances interim segment reporting requirements by aligning interim disclosures with information that must be disclosed annually in accordance with ASC 280. The guidance is effective for annual periods beginning after December 15, 2023, and interim periods

beginning after December 15, 2024, applied retrospectively with early adoption permitted. The Company is still evaluating the impact this ASU will have on its consolidated financial statements and related disclosures.

Retirement Plan

6 Months Ended

Jun. 30, 2024

Compensation And Retirement Disclosure [Abstract]

Retirement Plan

Note 15 – Retirement Plan

In July 2021, the Company adopted a 401(k) retirement savings plan that provides retirement benefits to all full-time employees. Eligible employees may contribute a percentage of their annual compensation, subject to Internal Revenue Service limitations. The Company contributed $0.1 million to the 401(k) retirement savings plan for each of the three months ended June 30, 2024 and 2023. The Company contributed $0.3 million and $0.2 million to the 401(k) retirement savings plan for the six months ended June 30, 2024 and 2023, respectively.

- Definition

The entire disclosure for retirement benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 70
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480794/715-70-50-1

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480482/715-20-55-17

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)(iv)(03)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (q)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (l)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//715/tableOfContent

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)(iii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (o)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (p)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (r)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (r)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480126/715-20-S99-2

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 60
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480266/715-60-50-3

+ Details

Stock-Based Compensation - Schedule of Stock Option Activity (Details) - Stock Options $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2024 USD ($) $ / shares shares	Dec. 31, 2023 USD ($) $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Outstanding. Stock Options, Beginning Balance \| shares	5,960,922
Options granted, Stock Options \| shares	9,220,821
Exercised, Stock Options \| shares	(2,062)
Options cancelled or forfeited, Stock Options \| shares	(534,893)
Options expired, Stock Options \| shares	(68,701)
Outstanding. Stock Options, Ending Balance \| shares	14,576,087	5,960,922
Options exercisable at March 31, 2024, Stock Options \| shares	2,667,407
Outstanding, Weighted Average Exercise Price, Beginning balance \| $ / shares	$ 5.75
Options granted, Weighted Average Exercise Price \| $ / shares	1.96
Exercised, Weighted Average Exercise Price \| $ / shares	1.18
Options cancelled or forfeited, Weighted Average Exercise Price \| $ / shares	2.29
Options expired, Weighted Average Exercise Price \| $ / shares	17.17
Outstanding, Weighted Average Exercise Price, Ending balance \| $ / shares	3.43	$ 5.75
Options exercisable at March 31, 2024, Weighted Average Exercise Price \| $ / shares	$ 9.05
Outstanding, Weighted Average Remaining Contractual Life	9 years	8 years 8 months 12 days
Options exercisable at March 31, 2024, Weighted Average Remaining Contractual Life	7 years 10 months 24 days
Outstanding, Aggregate Intrinsic Value, Beginning Balance \| $	$ 1,960
Outstanding, Aggregate Intrinsic Value, Ending Balance \| $	6,866	$ 1,960
Options exercisable at March 31, 2024, Aggregate Intrinsic Value \| $	$ 1,024

Balance Sheet Components - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 300	$ 400	$ 647	$ 674
Property, plant and equipment, net	10,513		10,513		$ 10,826
Assets Capitalized as Finance Leases
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net	$ 800		$ 800		$ 1,000

Net Loss Per Common Share - Schedule of Common Stock Equivalents Outstanding Excluded from Computation of Diluted Net Loss Per Share Attributable to Common Stockholders (Details) - shares	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per share	21,099,690	9,269,449
Unvested RSUs
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per share	4,631,935	492,497
Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per share	16,151,088	8,251,952
SSI Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per share	316,667	525,000

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Statement of Comprehensive Income [Abstract]
Net loss	$ (20,928)	$ (24,598)	$ (44,989)	$ (42,220)
Other comprehensive income:
Change in fair value of terms loan attributable to instrument specific credit risk	2,656		2,405
Comprehensive loss	$ (18,272)	$ (24,598)	$ (42,584)	$ (42,220)

- Definition

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income. Excludes changes in equity resulting from investments by owners and distributions to owners.

+ References + Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 323
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481687/323-10-50-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 28
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482907/825-10-50-28

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482765/220-10-50-6

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-3

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-8

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-9

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-4

Reference 13: http://www.xbrl.org/2003/role/exampleRef
-Topic 946
-SubTopic 830
-Name Accounting Standards Codification
-Section 55
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480167/946-830-55-10

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section 45
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483581/946-220-45-7

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(18))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483586/944-220-S99-1

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(9))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.6-09(1)(d))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-3

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(i))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A

Reference 20: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(ii))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A

Reference 21: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iii)(A))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A

Reference 22: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iv))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A

Reference 23: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(5))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A

Reference 24: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(i))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B

Reference 25: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iii)(A))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B

Reference 26: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iii)(B))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B

Reference 27: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iv))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B

Reference 28: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(5))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B

Reference 29: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 30
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-30

Reference 30: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 31: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 60B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-60B

Reference 32: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 31
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-31

Reference 33: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 34: http://www.xbrl.org/2003/role/disclosureRef
-Topic 205
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483499/205-20-50-7

Reference 35: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482740/230-10-45-28

Reference 36: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1A
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482790/220-10-45-1A

Reference 37: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482790/220-10-45-1B

Reference 38: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(20))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2

Reference 39: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(22))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1

+ Details

Warrants (Tables)

6 Months Ended

Jun. 30, 2024

Warrants and Rights Note Disclosure [Abstract]

Schedule of Fair Value Method to Allocate Net Proceeds Received from Sale of Common Stock and Pre-funded Warrants

The Company used the relative fair value method to allocate the net proceeds received from the sales of the PIPE Shares and the 2023 Pre-Funded Warrants on the consolidated balance sheet as follows (in thousands):


	Purchase Price Allocation
PIPE Shares	$	110,127
2023 Pre-Funded Warrants		39,826
Total	$	149,953

Schedule Of Assumptions Used To Estimate Fair Value Of Warrants

The following assumptions were used to estimate the fair value of the warrants at issuance:


Risk-free interest rate		3.46	%
Expected dividend yield	—
Expected term (in years)		5.2
Expected volatility		81	%
Market value of common stock (per share)	$	0.71

The Company estimated the fair value of the SSI Warrant liability using the following assumptions as of June 30, 2024:


Risk-free interest rate		4.43	%
Expected dividend yield	—
Expected term (in years)		4.4
Expected volatility		88	%
Market value of common stock (per share)	$	2.24

Schedule of Warrant Liability

The following table summarizes changes in the Company’s warrant liability during the six months ended June 30, 2024 (in thousands):


	Warrant Liability
Balance at January 1, 2024	$	454
Change in fair value		142
Balance at June 30, 2024	$	596

Balance Sheet Components - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Balance Sheet Related Disclosures [Abstract]
Accrued research and development	$ 2,613	$ 3,467
Accrued compensation	2,885	3,423
Accrued clinical trial	2,178	1,851
Lease liabilities, current portion	1,754	1,646
Accrued professional and consulting fees	1,072	330
Warrant liability	596	454
Accrued severance		390
Other	777	723
Total accrued expenses and other current liabilities	$ 11,875	$ 12,284

Term Loans - Additional Information (Details)			3 Months Ended		6 Months Ended		12 Months Ended	22 Months Ended
Term Loans - Additional Information (Details)	Nov. 13, 2023 USD ($)	Aug. 12, 2021 USD ($) Program	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)	Nov. 13, 2023 USD ($)	Dec. 31, 2021 USD ($)
Debt Instrument [Line Items]
Debt instrument, maturity date		Aug. 01, 2026
Percentage of interest rate		7.00%
Percentage of prepayment of facility		7.50%
Exit fee recorded as debt discount							$ 3,000,000
Success fee liability at fair value			$ 800,000		$ 800,000		800,000
Interest expense related to term loan			1,300,000	$ 1,400,000	2,600,000	$ 2,700,000
Prime Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		3.75%
Term Loan
Debt Instrument [Line Items]
Current borrowing capacity		$ 30,000,000							$ 10,000,000
Prepayment of long term debt							43,200,000
Payment of exit fee							3,000,000
Accrued interest							200,000
Remaining balance of debt discount							1,400,000
Trinity Term Loans
Debt Instrument [Line Items]
Fair value of loan at issuance			$ 37,835,000		$ 37,835,000		40,508,000
Trinity Term Loan Agreement
Debt Instrument [Line Items]
Percentage of calculated discounted cash flows of discount rate			15.68%		15.68%
Percentage of remeasured calculated discounted cash flows of discount rate			18.22%		18.22%
Trinity Term Loan Agreement \| Trinity Term Loans \| Trinity Lenders
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 40,000,000							$ 40,000,000
Interest rate terms description	The interest rate applicable to the Trinity Term Loans is the greater of (a) the Wall Street Journal (“WSJ”) Prime Rate plus 4.50% or (b) 12.75% per annum. The Trinity Term Loans are interest only from the Trinity Closing Date through 36 months from the Trinity Closing Date, which may be extended to 48 months from the Trinity Closing Date upon the satisfaction of certain milestones set forth in the Trinity Term Loan Agreement, after which the Company is required to pay equal monthly installments of principal through November 13, 2028 (the “Maturity Date”).
Debt instrument, maturity date	Nov. 13, 2028
Debt outstanding			$ 40,000,000		$ 40,000,000
Debt instrument, basis spread on variable rate	12.75%
Interest rate period	36 months
Interest rate extension period	48 months
Commitment fee percentage	1.00%
End of term payment percentage	5.00%
Warrants associated with loan facility	$ 0							0
Percentage of annual default interest rate	5.00%
Trinity Term Loan Agreement \| Trinity Term Loans \| Trinity Lenders \| Closing Date through November 13, 2024
Debt Instrument [Line Items]
Percentage of prepayment premium	3.00%
Trinity Term Loan Agreement \| Trinity Term Loans \| Trinity Lenders \| November 13, 2024 through November 13, 2025
Debt Instrument [Line Items]
Percentage of prepayment premium	2.00%
Trinity Term Loan Agreement \| Trinity Term Loans \| Trinity Lenders \| November 13, 2025 through, but excluding, the Maturity Date
Debt Instrument [Line Items]
Percentage of prepayment premium	1.00%
Trinity Term Loan Agreement \| Trinity Term Loans \| Trinity Lenders \| General and Administrative Expense
Debt Instrument [Line Items]
Debt issuance costs							$ 900,000
Trinity Term Loan Agreement \| Trinity Term Loans \| Prime Rate \| Trinity Lenders
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	4.50%
Success Fee Agreement
Debt Instrument [Line Items]
Percentage of calculated discounted cash flows of discount rate			15.68%		15.68%
Percentage of remeasured calculated discounted cash flows of discount rate			18.22%		18.22%
Success Fee Agreement \| Trinity Term Loans \| Trinity Lenders
Debt Instrument [Line Items]
Percentage of principal amount of terms regarding fee	10.00%
Expiration Period	10 years
Fair value of loan at issuance			$ 39,200,000		$ 39,200,000
Success fee liability at fair value			$ 800,000		$ 800,000
Through December 31, 2021 \| Term Loan
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 40,000,000
Debt instrument, maturity date		Dec. 31, 2021
January 1, 2022 until September 30, 2022 \| Term Loan
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 20,000,000
Debt instrument, maturity start date		Jan. 01, 2022
Debt instrument, maturity end date		Sep. 30, 2022
Number of distinct and active clinical stage \| Program		3
January 1, 2022 until March 31, 2023 \| Term Loan
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 20,000,000
Debt instrument, maturity end date		Mar. 31, 2023
Proceeds from term loan								$ 0
October 1, 2022 until March 31, 2023 \| Term Loan
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 20,000,000
Debt instrument, maturity start date		Oct. 01, 2022
Debt instrument, maturity end date		Mar. 31, 2023
Number of distinct and active clinical stage \| Program		3
April 1, 2023 until December 31, 2023 \| Term Loan
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 20,000,000
Debt instrument, maturity start date		Apr. 01, 2023
Debt instrument, maturity end date		Dec. 31, 2023
Through August 13, 2023
Debt Instrument [Line Items]
Percentage of prepayment premium		1.00%

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Cash flows from operating activities
Net loss			$ (44,989)	$ (42,220)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	$ 300	$ 400	647	674
Stock-based compensation			6,530	3,897
Research and development license expense				3,500
Change in fair value of warrant liability			142
Non-cash change in fair value of term loan			(268)
Non-cash lease expense			619	603
Other			1	387
Changes in operating assets and liabilities:
Prepaid expenses and other assets			129	509
Accounts payable			2,365	2,123
Accrued expenses and other liabilities			(1,955)	(1,324)
Deferred revenue			(4,523)	(7,101)
Net cash used in operating activities			(41,302)	(38,952)
Cash flows from investing activities
Purchase of property, plant and equipment			(341)	(3,852)
Net cash used in investing activities			(341)	(3,852)
Cash flows from financing activities
Debt issuance costs for term loan			(18)
Proceeds from issuance of common stock and pre-funded warrants from underwritten public offering, net of underwriting discounts and sales commissions and other offering costs			70,481
Payment of offering costs				(387)
Proceeds from common stock issuances under ESPP			26	50
Other			(43)	(156)
Net cash provided by financing activities			70,446	7
Net increase (decrease) in cash, cash equivalents and restricted cash			28,803	(42,797)
Cash, cash equivalents and restricted cash at the beginning of the period			146,540	90,517	$ 90,517
Cash, cash equivalents and restricted cash at the end of the period	175,343	47,720	175,343	47,720	146,540
Cash and cash equivalents	172,743	45,083	172,743	45,083	$ 143,940
Restricted cash	$ 2,600	$ 2,637	2,600	2,637
Supplemental disclosure of cash flow information:
Cash paid for interest			2,655	2,399
Supplemental disclosure of noncash investing and financing activities:
Issuance of warrants in connection with private placement				252
Research and development license not yet paid				3,500
Offering costs not yet paid			$ 445
Private Placement
Cash flows from financing activities
Proceeds from issuance of common stock from private placement				$ 500

Stock-Based Compensation - Schedule of Assumptions Used to Estimate Fair Value of Stock Options (Details)	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	May 31, 2023	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate		4.55%	3.72%	4.04%	3.61%
Expected term (in years)		5 years 10 months 24 days	5 years 9 months 18 days	6 years 1 month 6 days	5 years 10 months 24 days
Expected volatility		89.00%	81.00%	89.00%	81.00%
Performance Stock Options \| Initial Options and Original Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate	4.02%
Expected term (in years)	6 years
Expected volatility	81.00%
Performance Stock Options \| Modified Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate						3.90%
Expected term (in years)						5 years 9 months 18 days
Expected volatility						88.00%

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 35
-Paragraph 1D
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480483/718-10-35-1D

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 35
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480483/718-10-35-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(ii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(01)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(02)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(03)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(04)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(ii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(01)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(02)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(03)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 20: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 21: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 22: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (e)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 23: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (e)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 24: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 25: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(ii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 26: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(iii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 27: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(iv)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 28: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(v)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

+ Details

Warrants

6 Months Ended

Jun. 30, 2024

Warrants and Rights Note Disclosure [Abstract]

Warrants

Note 10—Warrants

Pre-Funded Warrants

Pre-Funded Warrants Issued in August 2023

On August 14, 2023, the Company entered into a Securities Purchase Agreement (the “August 2023 Purchase Agreement”) with certain institutional and other accredited investors (the “Purchasers”), pursuant to which the Company agreed to sell and issue to the Purchasers in a private placement transaction (the “August 2023 Private Placement”) (i) 122,412,376 shares (the “PIPE Shares”) of the Company’s common stock, and (ii) with respect to certain Purchasers, pre-funded warrants to purchase 44,250,978 shares of the Company’s common stock (the “2023 Pre-Funded Warrants”) in lieu of shares of the Company’s common stock. The purchase price per share of common stock was $0.90 per share (the “PIPE Purchase Price”), and the purchase price for the 2023 Pre-Funded Warrants was the PIPE Purchase Price minus $0.001 per Pre-Funded Warrant.

The 2023 Pre-Funded Warrants have a per share exercise price of $0.001, subject to proportional adjustments in the event of stock splits or combinations or similar events. The Pre-Funded Warrants will not expire until exercised in full. The 2023 Pre-Funded Warrants may not be exercised if the aggregate number of shares of common stock beneficially owned by the holder thereof immediately following such exercise would exceed a specified beneficial ownership limitation; provided, however, that a holder may increase or decrease the beneficial ownership limitation by giving 61 days’ notice to the Company, but not to any percentage in excess of 19.99%. The exercise of the 2023 Pre-Funded Warrants was also contingent upon receipt of stockholder approval of an increase in the authorized shares of the Company’s common stock (the “Stockholder Approval”), which the Company obtained at a special meeting of stockholders held on November 15, 2023.

The closing of the August 2023 Private Placement occurred on August 16, 2023 (the “PIPE Closing”). The total gross proceeds to the Company at the PIPE Closing were $150.0 million, and after deducting placement agent commissions and offering expenses payable by the Company, net proceeds were $140.3 million. The Company used the with-and-without method to allocate the total gross proceeds by first allocating the portion of the proceeds equal to the fair value of the 2023 Pre-Funded Warrants on the PIPE Closing date with the remaining proceeds allocated to the PIPE Shares on a residual basis.

The Company concluded that at the closing of the August 2023 Private Placement in August 2023, the 2023 Pre-Funded Warrants did not meet the criteria for equity classification under the guidance of ASC 815 as the Company did not have sufficient authorized and unissued shares to satisfy the warrants if exercised. The Company recorded the 2023 Pre-Funded Warrants as liabilities at their fair value. This liability is subject to remeasurement at each balance sheet date and any change in fair value is recognized in the Company’s consolidated statements of operations. The Company incurred $9.7 million of placement agent commissions and other issuance costs in connection with the August 2023 Private Placement. The placement agent commissions and other issuance costs were allocated between the PIPE Shares and the 2023 Pre-Funded Warrants on a systematic basis. The Company allocated $7.1 million to the PIPE Shares which was recorded as a deduction to additional paid-in capital. The remaining $2.6 million allocated to the 2023 Pre-Funded Warrants were recorded within general and administrative expense in the consolidated statements of operations for the year ended December 31, 2023. The issuance costs allocated to the 2023 Pre-Funded Warrants have been added back to net loss

when deriving cash flows used in operations, and have been classified as a financing cash outflow in the consolidated statements of cash flows for the year ended December 31, 2023.

The Company measured the fair value of the PIPE Shares and 2023 Pre-Funded Warrants based on the $0.90 per share Purchase Price. The Company used the relative fair value method to allocate the net proceeds received from the sales of the PIPE Shares and the 2023 Pre-Funded Warrants on the consolidated balance sheet as follows (in thousands):


	Purchase Price Allocation
PIPE Shares	$	110,127
2023 Pre-Funded Warrants		39,826
Total	$	149,953

The Company remeasured the fair value of the 2023 Pre-Funded Warrants using the closing price of the Company’s common stock on the Nasdaq Global Market as of November 15, 2023 of $1.68 per common share upon receipt of Stockholder Approval. The Company recorded a fair value adjustment of $34.5 million in the consolidated statements of operations for the year ended December 31, 2023 and the warrant liability of $74.3 million was reclassified into equity as an increase to additional paid-in capital upon receipt of Stockholder Approval.

Pre-Funded Warrants Issued in June 2024

On June 26, 2024, the Company entered into the June 2024 Underwriting Agreement with the Underwriters to issue and sell 14,361,113 shares of common stock, and, in lieu of common stock to certain investors, pre-funded warrants to purchase 18,972,221 shares of common stock (the “June 2024 Pre-Funded Warrants”) in the June 2024 Offering. The offering price to the public was $2.25 per share of common stock and $2.249 per June 2024 Pre-Funded Warrant, which was the price to the public of each share of common stock sold in the June 2024 Offering, minus the $0.001 exercise price per June 2024 Pre-Funded Warrant. The Underwriters agreed to purchase the shares and the June 2024 Pre-Funded Warrants from the Company pursuant to the June 2024 Underwriting Agreement at a price of $2.115 per share and $2.114 per June 2024 Pre-Funded Warrant, respectively. The initial closing of the June 2024 Offering occurred on June 27, 2024; no additional June 2024 Pre-Funded Warrants were sold upon the exercise of the Underwriters’ option in July 2024.

Each June 2024 Pre-Funded Warrant has an initial exercise price per share of $0.001, subject to certain adjustments. The June 2024 Pre-Funded Warrants may be exercised at any time until exercised in full, except that a holder will not be entitled to exercise any portion of any pre-funded warrant, which, upon giving effect to such exercise would cause (i) the aggregate number of shares of the Company’s common stock beneficially owned by the holder (together with its affiliates) to exceed 4.99% or 9.99%, as the case may be, of the number of shares of the Company’s common stock outstanding immediately prior to or after giving effect to the exercise, or (ii) the combined voting power of the Company’s securities beneficially owned by the holder (together with its affiliates) to exceed 4.99% or 9.99%, as the case may be, of the combined voting power of all of the Company’s securities then outstanding immediately prior to or after giving effect to the exercise, as such percentage ownership is determined in accordance with the terms of the pre-funded warrants, subject to such holder’s rights under the June 2024 Pre-Funded Warrant to increase or decrease such percentage to another percentage not in excess of 19.99% upon at least 61 days’ prior notice from such holder to the Company.

The Company concluded that the June 2024 Pre-Funded Warrants meet the criteria for equity classification at issuance and were recorded as a component of stockholders’ equity within additional paid-in capital. The June 2024 Pre-funded Warrants are equity classified because they (i) are freestanding financial instruments that are legally detachable and separately exercisable from the equity instruments, (ii) are immediately exercisable, (iii) do not embody an obligation for the Company to repurchase its shares, (iv) permit the holders to receive a fixed number of shares of common stock upon exercise, (v) are indexed to the Company’s common stock and (vi) meet the equity classification criteria. In addition, such pre-funded warrants do not provide any guarantee of value or return.

SSI Warrants

In April 2023, the Company entered into a securities purchase agreement (the “SSI Securities Purchase Agreement”), with two affiliates of SSI Strategy Holdings LLC (“SSI”), named therein (the “SSI Investors”) pursuant to which the Company agreed to issue and sell to the SSI Investors in a private placement (the “SSI Private Placement”), 705,218 shares of its common stock (the “SSI Shares”) and warrants (the “SSI Warrants”) to purchase an aggregate of 525,000 shares of the Company’s common stock (the “Warrant Shares”). SSI provides certain consulting services to the Company. Each SSI Warrant has an exercise price of $0.7090 per Warrant Share, which was the closing price of the Company’s common stock on the Nasdaq Global Market on April 4, 2023 and expire ten years after issuance. The SSI Warrants issued in the SSI Private Placement provide that the holder of the SSI Warrants will not have the right to exercise any portion of its SSI Warrants until the achievement of certain clinical and regulatory milestones related to the Company’s clinical programs. The SSI Private Placement closed on April 5, 2023. Gross proceeds of the SSI Private Placement were $0.5 million.

The Company concluded that the SSI Warrants do not meet the criteria for equity classification under the guidance of ASC 815 due to settlement provisions that permit the holder to receive a variable number of shares in the event of a specified fundamental transaction as well as provisions that permit the holder to participate in dividends. As the SSI Warrants do not meet the criteria for equity classification, the Company recorded the warrants as liabilities at their fair value. This liability is subject to remeasurement at each balance sheet date until the warrants are exercised or expire, and any change in fair value is recognized in the Company’s condensed consolidated statements of operations.

The Company determined the fair value of the SSI Warrants at issuance was $0.3 million using the Black-Scholes-Merton option pricing model. The following assumptions were used to estimate the fair value of the warrants at issuance:


Risk-free interest rate		3.46	%
Expected dividend yield	—
Expected term (in years)		5.2
Expected volatility		81	%
Market value of common stock (per share)	$	0.71

The fair value adjustment as of June 30, 2024 was $0.1 million using the Black-Scholes-Merton option pricing model. As of June 30, 2024, 316,667 of the SSI Warrants have vested and are exercisable. No warrants were exercised during the period.

The Company estimated the fair value of the SSI Warrant liability using the following assumptions as of June 30, 2024:


Risk-free interest rate		4.43	%
Expected dividend yield	—
Expected term (in years)		4.4
Expected volatility		88	%
Market value of common stock (per share)	$	2.24

The following table summarizes changes in the Company’s warrant liability during the six months ended June 30, 2024 (in thousands):


	Warrant Liability
Balance at January 1, 2024	$	454
Change in fair value		142
Balance at June 30, 2024	$	596

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Income Statement [Abstract]
Revenue	$ 1,112	$ 2,395	$ 4,523	$ 7,101
Operating expenses:
Research and development	15,073	19,791	35,730	32,305
General and administrative	7,338	5,988	14,422	14,739
Total operating expenses	22,411	25,779	50,152	47,044
Loss from operations	(21,299)	(23,384)	(45,629)	(39,943)
Other income (expense):
Change in fair value of warrant liability	195		(142)
Change in fair value of term loan	(1,279)		(2,332)
Interest income	1,440	223	3,133	542
Interest expense	(27)	(1,440)	(56)	(2,814)
Other (expense) income	42	3	37	(5)
Total other income (expense), net	371	(1,214)	640	(2,277)
Net loss	$ (20,928)	$ (24,598)	$ (44,989)	$ (42,220)
Net loss per common share, basic	$ (0.09)	$ (0.38)	$ (0.19)	$ (0.66)
Net loss per common share, diluted	$ (0.09)	$ (0.38)	$ (0.19)	$ (0.66)
Weighted average common shares outstanding, basic	232,821,553	64,244,531	232,035,448	63,755,435
Weighted average common shares outstanding, diluted	232,821,553	64,244,531	232,035,448	63,755,435

Organization and Description of Business Operations - Additional Information (Details) - USD ($)					1 Months Ended	3 Months Ended	6 Months Ended
	Jul. 09, 2024	Jul. 09, 2024	Aug. 16, 2023	Oct. 05, 2021	Apr. 30, 2022	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Jun. 26, 2024	Dec. 31, 2023	Oct. 31, 2022	Oct. 21, 2022
Organization and Description of Business Operations [Line Items]
Date of incorporation							Feb. 13, 2020
Common stock, shares issued							201,381,450			186,960,193
Common stock, par value per share							$ 0.00001			$ 0.00001
Accumulated deficit							$ (557,996,000)			$ (513,007,000)
Cash and cash equivalents						$ 45,083,000	$ 172,743,000	$ 45,083,000		$ 143,940,000
Private Placement
Organization and Description of Business Operations [Line Items]
Net proceeds from issuance of common stock								$ 500,000
Private Placement \| Common Stock
Organization and Description of Business Operations [Line Items]
Number of shares issued						705,218		705,218
Sales Agreement
Organization and Description of Business Operations [Line Items]
Common stock shares issued and sold							0
Number of shares issued					2,000,000
Net proceeds from issuance of common stock					$ 11,600,000
Sales Agreement \| Sales Agents
Organization and Description of Business Operations [Line Items]
Percentage of gross sales price per share of common stock				3.00%
Sales Agreement \| Sales Agents \| Maximum
Organization and Description of Business Operations [Line Items]
Aggregate offering price from sale of common stock				$ 150,000,000
Securities Purchase Agreement \| Private Placement
Organization and Description of Business Operations [Line Items]
Net proceeds from issuance of common stock			$ 150,000,000
Securities Purchase Agreement \| Private Placement \| Astellas
Organization and Description of Business Operations [Line Items]
Common stock, shares issued											7,266,342	7,266,342
Underwriting Agreement
Organization and Description of Business Operations [Line Items]
Common stock, shares issued									14,361,113
Option to purchase additional number of common shares									5,000,000
Underwriter agreed to purchase share price of per share									$ 2.115
Underwriting Agreement \| Common Stock
Organization and Description of Business Operations [Line Items]
Underwriter agreed to purchase share price of per share									2.115
Offering price per share of common stock									$ 2.25
Underwriting Agreement \| Pre-Funded Warrants
Organization and Description of Business Operations [Line Items]
Warrants issued									18,972,221
Exercise price of warrants Per Share									$ 0.001
Underwriter agreed to purchase share price of per share									2.114
Offering price per share of common stock									$ 2.249
Underwriting Agreement \| Subsequent Event
Organization and Description of Business Operations [Line Items]
Net proceeds from issuance of common stock	$ 6,800,000	$ 76,800,000
Option to purchase additional number of common shares	3,235,000	3,235,000

Astellas Agreements

6 Months Ended

Jun. 30, 2024

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Astellas Agreements

Note 8—Research, Collaboration and License Agreements

UT Southwestern Agreement

agreement or insolvency of the other party. In December 2023, the Company transferred rights to specific indications back to UT Southwestern.

Queen’s Agreement

Abeona CLN1 Agreements

Abeona Rett Agreement

TSHA-120 for the treatment of GAN

License Agreement for CLN7

No additional milestone payments were made or triggered in connection with this agreement during the six months ended June 30, 2024.

Astellas

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Astellas Agreements

Note 6—Astellas Agreements

On October 21, 2022 (the “Effective Date”), the Company entered into the Option Agreement (the “Option Agreement”) with Astellas Gene Therapies, Inc. (f/k/a Audentes Therapeutics, Inc. (d/b/a Astellas Gene Therapy))(“Astellas”), pursuant to which the Company granted to Astellas an exclusive option to obtain an exclusive, worldwide, royalty and milestone-bearing right and license (A) to research, develop, make, have made, use, sell, offer for sale, have sold, import, export and otherwise exploit, or, collectively, exploit, the product known, as of the Effective Date, as TSHA-120 (the “120 GAN Product”), and any backup products with respect thereto for use in the treatment of Giant Axonal Neuropathy (“GAN”) or any other gene therapy product for use in the treatment of GAN that is controlled by Taysha or any of its affiliates or with respect to which the Company or any of its affiliates controls intellectual property rights covering the exploitation thereof (a “GAN Product”) and (B) under any intellectual property rights controlled by Taysha or any of its affiliates with respect to such exploitation (the “GAN Option”). Subject to certain extensions, the GAN Option was exercisable from the Effective Date through a specified period of time following Astellas’ receipt of (i) the formal minutes from the Type B end-of-Phase 2 meeting between Taysha and the FDA in response to the Company’s meeting request sent to the FDA on September 19, 2022 for the 120 GAN Product (the “Type B end-of-Phase 2 Meeting”), (ii) all written feedback from the FDA with respect to the Type B end-of-Phase 2 Meeting, and (iii) all briefing documents sent by Taysha to the FDA with respect to the Type B end-of-Phase 2 Meeting. In September 2023, Astellas provided written notice of its decision not to exercise the GAN Option.

Under the Option Agreement, the Company also granted to Astellas an exclusive option to obtain an exclusive, worldwide, royalty and milestone-bearing right and license (A) to exploit any Rett Product (as defined below), and (B) under any intellectual property rights controlled by Taysha or any of its affiliates with respect to such exploitation (the “Rett Option,” and together with the GAN Option, each, an “Option”). Subject to certain extensions, the Rett Option is exercisable from the Effective Date through a specified period of time following Astellas’ receipt of (i) certain clinical data from the female pediatric trial and (ii) certain specified

data with respect to TSHA-102, such period, the Rett Option Period, related to (i) the product known, as of the Effective Date, as TSHA-102 and any backup products with respect thereto for use in the treatment of Rett syndrome, and (ii) any other gene therapy product for use in the treatment of Rett syndrome that is controlled by Taysha or any of its affiliates or with respect to which the Company or any of its affiliates controls intellectual property rights covering the exploitation thereof (a “Rett Product”).

The parties have agreed that, if Astellas exercises an Option, the parties will, for a specified period, negotiate a license agreement in good faith on the terms and conditions outlined in the Option Agreement, including payments by Astellas of a to be determined upfront payment, certain to be determined milestone payments, and certain to be determined royalties on net sales of GAN Products and/or Rett Products, as applicable.

During the Rett Option Period, the Company has agreed to (A) not solicit or encourage any inquiries, offers or proposals for, or that could reasonably be expected to lead to, a Change of Control (as defined in the Option Agreement), or (B) otherwise initiate a process for a potential Change of Control, in each case, without first notifying Astellas and offering Astellas the opportunity to submit an offer or proposal to the Company for a transaction that would result in a Change of Control. If Astellas fails or declines to submit any such offer within a specified period after the receipt of such notice, the Company will have the ability to solicit third party bids for a Change of Control transaction. If Astellas delivers an offer to the Company for a transaction that would result in a Change of Control, the Company and Astellas will attempt to negotiate in good faith the potential terms and conditions for such potential transaction that would result in a Change of Control for a specified period, which period may be shortened or extended by mutual agreement.

As partial consideration for the rights granted to Astellas under the Option Agreement, Astellas paid the Company an upfront payment of $20.0 million (the “Upfront Payment”). Astellas or any of its affiliates shall have the right, in its or their discretion and upon written notice to the Company, to offset the amount of the Upfront Payment (in whole or in part, until the full amount of the Upfront Payment has been offset) against (a) any payment(s) owed to Taysha or any of its affiliates (or to any third party on behalf of the Company) under or in connection with any license agreement entered into with respect to any GAN Product or Rett Product, including, any upfront payment, milestone payment or royalties owed to Taysha or any of its affiliates (or to any third party on behalf of the Company) under or in connection with any such license agreement or (b) any amount owed to Taysha or any of its affiliates in connection with a Change of Control transaction with Astellas or any of its affiliates. As further consideration for the rights granted to Astellas under the Option Agreement, the Company and Astellas also entered into the Astellas Securities Purchase Agreement (as defined below).

Astellas Securities Purchase Agreement

On October 21, 2022, the Company entered into a securities purchase agreement with Astellas (the “Astellas Securities Purchase Agreement”), pursuant to which the Company agreed to issue and sell to Astellas in a private placement (the “Astellas Private Placement”), an aggregate of 7,266,342 shares (the “Astellas Private Placement Shares”), of its common stock, for aggregate gross proceeds of $30.0 million. The Astellas Private Placement closed on October 24, 2022. Pursuant to the Securities Purchase Agreement, in connection with the Astellas Private Placement, Astellas has the right to designate one individual to attend all meetings of the Board in a non-voting observer capacity. The Company also granted Astellas certain registration rights with respect to the Astellas Private Placement Shares.

Accounting Treatment

In October 2022, upon closing of the Astellas Private Placement and transferring the 7,266,342 shares to Astellas, the Company recorded the issuance of shares at fair value. Fair value of the shares transferred to Astellas was calculated in accordance with ASC 820, Fair Value Measurement by analyzing the Company’s stock price for a short period of time prior to and after the transaction date as traded on the NASDAQ. The NASDAQ trading data is considered an active market and a Level 1 measurement under ASC 820. The fair value was determined to be approximately $13.95 million or $1.92 per share. The $16.1 million difference between the $30.0 million paid by Astellas and the fair market value of shares issued was allocated to the transaction price of the Option Agreement.

The Company determined that the Option Agreement falls within the scope of ASC 606, Revenue from Contracts with Customers as the development of TSHA-102 for the treatment of Rett Syndrome and TSHA-120 for the treatment of GAN are considered ordinary activities for the Company. In accordance with ASC 606, the Company evaluated the Option Agreement and identified three separate performance obligations: (1) option to obtain licensing right to GAN, (2) option to obtain licensing right to Rett and (3) performance of research and development activities in the Rett development plan. The transaction price is determined to be $36.1 million which is comprised of the $20.0 million Upfront Payment and the $16.1 million allocated from the Private Placement.

To determine the standalone selling price (“SSP”) of the Rett and GAN options, which the Company concluded to be material rights, the Company utilized the probability-weighted expected return (“PWERM”) method. The PWERM method contemplates the probability and timing of an option exercise. At contract inception, the Company estimated that the probability of exercise was 50% for each of the GAN and Rett options. The SSP of the Rett research and development activities was estimated using an expected cost-plus margin approach. The standalone selling prices of the material rights and Rett research and development activities were then used to proportionately allocate the $36.1 million transaction price to the three performance obligations. The $36.1 million transaction price was recorded as deferred revenue on the condensed consolidated balance sheet at the inception of the Astellas Transactions.

The following table summarizes the allocation of the transaction price to the three performance obligations at contract inception (amounts in thousands):


	Transaction Price Allocation
Option to obtain license for Rett	$	5,485
Option to obtain license for GAN		2,317
Rett research and development activities		28,257
Total	$	36,059

Revenue allocated to the material rights will be recognized at a point in time when each option period expires or when a decision is made by Astellas to exercise or not exercise each option. Revenue from the Rett research and development activities will be recognized as activities are performed using an input method, according to the costs incurred as related to the total costs expected to be incurred to satisfy the performance obligation. The transfer of control occurs over this time period and is a reliable measure of progress towards satisfying the performance obligation.

During the six months ended June 30, 2024, the Company determined that the total estimated costs to be incurred to satisfy the performance obligation associated with Rett research and development activities had increased from the cost estimate used for the year ended December 31, 2023, and the three months ended March 31, 2024. The cumulative impact of this change would have resulted in a $1.1 million decrease related to revenue previously recognized based on prior cost estimates.

The Company recognized revenue of $1.1 million and $2.4 million from Rett research and development activities for the three months ended June 30, 2024 and 2023, respectively. The Company recognized revenue of $4.5 million and $7.1 million from Rett research and development activities for the six months ended June 30, 2024 and 2023, respectively.

The Company had $13.6 million of deferred revenue on the condensed consolidated balance sheet as of June 30, 2024 comprised of $5.5 million for the Rett Option and $8.1 million of Rett research and development activities. The Company had $18.1 million of deferred revenue on the condensed consolidated balance sheet as of December 31, 2023 comprised of $5.5 million for the Rett Option and $12.6 million of Rett research and development activities. The GAN option revenue was recognized in September 2023 when Astellas provided written notice of its decision not to exercise the GAN Option.

Stock-Based Compensation

6 Months Ended

Jun. 30, 2024

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation

Note 9—Stock-Based Compensation

On July 1, 2020, the Company’s board of directors approved the 2020 Equity Incentive Plan (“Previous Plan”) which permitted the granting of incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock awards (“RSAs”), restricted stock units (“RSUs”) and other stock-based awards to employees, directors, officers and consultants. As of September 16, 2020, the approval date of the New Plan (as defined below), no additional awards will be granted under the Previous Plan. The terms of the Previous Plan will continue to govern the terms of outstanding equity awards that were granted prior to approval of the New Plan.

On September 16, 2020, the Company’s stockholders approved the 2020 Stock Incentive Plan (“New Plan”), which became effective upon the execution of the underwriting agreement in connection with the IPO. The number of shares of common stock reserved for issuance under the New Plan automatically increases on January 1 of each year, for a period of ten years, from January 1, 2021, continuing through January 1, 2030, by 5% of the total number of shares of common stock outstanding on December 31 of the preceding calendar year, or a lesser number of shares as may be determined by the Company’s board of directors. Pursuant to this provision, on January 1, 2024, the Company increased the number of shares of common stock reserved for issuance under the New Plan by 9,348,009 shares.

Furthermore, on September 16, 2020, the Company’s stockholders approved the Employee Stock Purchase Plan (“ESPP”), which became effective upon the execution of the underwriting agreement in connection with the IPO. The maximum number of shares of common stock that may be issued under the ESPP will not exceed 362,000 shares of common stock, plus the number of shares of common stock that are automatically added on January 1st of each year for a period of up to ten years, commencing on the first January 1 following the IPO and ending on (and including) January 1, 2030, in an amount equal to the lesser of (i) one percent (1.0%) of the total number of shares of capital stock outstanding on December 31st of the preceding calendar year, and (ii) 724,000 shares of common stock. No shares were added to the ESPP in 2021. Pursuant to this provision, on January 1, 2023 and 2024, the Company increased the number of shares of common stock reserved for issuance under the ESPP by 632,075 and 724,000 respectively. The Company has issued an aggregate of 188,193 shares of common stock under the ESPP as of June 30, 2024.

On December 15, 2023, the Company’s board of directors adopted the Taysha Gene Therapies, Inc. 2023 Inducement Plan (the “Inducement Plan”). The Inducement Plan was adopted without stockholder approval pursuant to Nasdaq Listing Rule 5635(c)(4). The Board reserved 4,000,000 shares of the Company’s common stock for issuance under the Inducement Plan.

The only persons eligible to receive grants of Inducement Awards (as defined below) under the Inducement Plan are individuals who satisfy the standards for inducement grants under Nasdaq Listing Rule 5635(c)(4). The Inducement Plan will be administered by the Board and the Company’s Compensation Committee. Inducement Awards may only be granted by: (i) the Compensation Committee, provided such committee is comprised solely of “independent directors” (as defined by Nasdaq Listing Rule 5605(a)(2)) or (ii) a majority of the Company’s “independent directors.” An “Inducement Award” means any right to receive the Company’s common stock, cash or other property granted under the Inducement Plan (including nonstatutory stock options, restricted stock awards, restricted stock unit awards, stock appreciation rights, performance stock awards, performance cash awards or other stock-based awards).

The number of shares available for grant under the Company’s incentive plans were as follows:


	New			Inducement
	Plan			Plan			Total
Available for grant - January 1, 2024		3,162,725			4,000,000			7,162,725
Plan adjustments and amendments		9,348,009			—			9,348,009
Grants		(11,905,262	)		(1,812,700	)		(13,717,962	)
Forfeitures		298,646			311,000			609,646
Available for grant - June 30, 2024		904,118			2,498,300			3,402,418

Stock Options

For the three months ended June 30, 2024, 1,421,760 shares of common stock under the New Plan and the Inducement Plan were awarded with a weighted-average grant date fair value per share of $2.25. The stock options vest over four years and have a ten-year contractual term. For the six months ended June 30, 2024, 9,220,821 shares of common stock under the New Plan and the

Inducement Plan were awarded with a weighted-average grant date fair value per share of $1.49. The stock options vest over one to four years and have a ten-year contractual term.

The following weighted-average assumptions were used to estimate the fair value of time-based vesting stock options that were granted during the three and six months ended June 30, 2024 and 2023:


	Three Months Ended June 30,						Six Months Ended June 30,
	2024			2023			2024			2023
Risk-free interest rate		4.55	%		3.72	%		4.04	%		3.61	%
Expected dividend yield		—			—			—			—
Expected term (in years)		5.9			5.8			6.1			5.9
Expected volatility		89	%		81	%		89	%		81	%

The following table summarizes time-based vesting stock option activity, during the six months ended June 30, 2024:


						Weighted
				Weighted		Average		Aggregate
				Average		Remaining		Intrinsic
	Stock			Exercise		Contractual		Value
	Options			Price		Life (in years)		(in thousands)
Outstanding at January 1, 2024		5,960,922		$	5.75		8.7	$	1,960
Options granted		9,220,821			1.96
Exercised		(2,062	)		1.18
Options cancelled or forfeited		(534,893	)		2.29
Options expired		(68,701	)		17.17
Outstanding at June 30, 2024		14,576,087		$	3.43		9.0	$	6,866
Options exercisable at June 30, 2024		2,667,407		$	9.05		7.9	$	1,024

The aggregate intrinsic value in the above table is calculated as the difference between the fair value of the Company’s common stock at the respective reporting date and the exercise price of the stock options. As of June 30, 2024, the total unrecognized compensation related to unvested stock option awards granted was $16.9 million, which the Company expects to recognize over a weighted-average period of approximately 2.7 years.

Performance Stock Options

In February 2023, the Company issued options to purchase 70,235 shares of common stock to employees under the New Plan that contain performance-based vesting conditions, subject to continued employment through each anniversary and achievement of the performance conditions. The grant date fair value of these awards was not material. As of June 30, 2024, 58,346 of the shares subject to the performance-based options were vested and outstanding. No performance-based stock options were exercised during the period.

In May 2023, the Company issued options to purchase 2,166,653 shares of common stock to employees under the New Plan that contain both service and performance-based vesting conditions (the “Original Options”), with a weighted average grant date fair value per share of $0.50. These Original Options were expected to vest over a 3.6 year term if a combination of clinical, regulatory and financing performance conditions were achieved. No compensation expense was recognized in 2023 related to the Original Options as achievement of the performance conditions was not considered probable. The following weighted-average assumptions were used to estimate the fair value of the options granted in February 2023 and the Original Options that were granted in May 2023:




Risk-free interest rate	4.02	%
Expected dividend yield	—
Expected term (in years)	6.0
Expected volatility	81	%

In December 2023, the Company modified all of the Original Options to amend the clinical and regulatory performance conditions and decreased the number of options granted to 1,516,655 (the “Modified Options”). The Company accounted for the changes in award terms as a modification in accordance with ASC 718, Compensation - Stock Compensation. Total compensation cost

is equal to the modification date fair value. The Modified Options have a grant date fair value per share of $1.28. The following assumptions were used to estimate the fair value of the Modified Options:



Risk-free interest rate	3.90	%
Expected dividend yield	—
Expected term (in years)	5.8
Expected volatility	88	%

The Modified Options will vest over 3.0 years. The Company recognized stock-based compensation expense of $0.3 million and $0.6 million for the three and six months ended June 30, 2024, respectively, related to the Modified Options. As of June 30, 2024, the total unrecognized compensation expense related to the Modified Options was $1.3 million, which the Company expects to recognize over a weighted average period of approximately 1.7 years using the accelerated attribution method. As of June 30, 2024, 1,516,655 of the Modified Options were outstanding. No Modified Options vested or were exercised during the period.

Market-based Stock Options

In February 2023, the Company issued options to purchase 70,233 shares of common stock to employees under the New Plan that contain a market-based vesting condition, subject to continued employment through each anniversary and achievement of the market condition. The grant date fair value of the stock options that contain market-based vesting conditions was not material. As of December 31, 2023, the market condition was not met and all 70,233 shares were forfeited.

Restricted Stock Units

For the six months ended June 30, 2024, the Company issued 4,497,141 RSUs to employees under the New Plan. The RSUs are subject to a service-based vesting condition. The service-based RSUs vest in equal annual installments over a four-year period. The Company at any time may accelerate the vesting of the RSUs. Such shares are not accounted for as outstanding until they vest.

The Company’s default tax withholding method for RSUs granted prior to 2023 is the sell-to-cover method, in which shares with a market value equivalent to the tax withholding obligation are sold on behalf of the holder of the RSUs upon vesting and settlement to cover the tax withholding liability and the cash proceeds from such sales are remitted by the Company to taxing authorities. For RSUs granted in 2023, the Company’s tax withholding policy allows the RSU holder to choose to either pay cash to the Company for the tax withholding obligation or elect the net withholding method, in which shares with a market equivalent to the tax withholding obligation are withheld and the net shares are issued to the RSU holder.

The Company’s RSU activity for the six months ended June 30, 2024 was as follows:


				Weighted
				Average
				Grant Date
	Number			Fair Value
	of Shares			per Share
Nonvested at January 1, 2024		375,044		$	6.63
Restricted units granted		4,497,141			1.83
Vested		(240,250	)		4.96
Cancelled or forfeited		—			—
Nonvested at June 30, 2024		4,631,935		$	2.06

As of June 30, 2024, there were 222,216 vested and unsettled RSU awards with a weighted average grant date fair value of $5.25 per share.

As of June 30, 2024, the total unrecognized compensation cost related to the unvested RSU's was $7.6 million which is expected to be amortized on a straight-line basis over a weighted-average period of approximately 3.2 years.

Performance and Market-based Restricted Stock Units

In February 2023, the Company issued 81,233 RSUs to employees under the New Plan that contain a combination of performance and market-based vesting conditions, subject to continued employment through each anniversary and achievement of market and performance conditions. The grant date fair value of the RSUs that contain performance and market-based vesting conditions was not material. As of December 31, 2023, 46,562 of the RSUs were forfeited and 34,671 RSUs vested and were settled.

No RSUs that contain performance or market-based vesting conditions were granted or outstanding during the six months ended June 30, 2024.

Employee Stock Purchase Plan

In February 2022, the Company’s board of directors authorized the first offering under the ESPP. Under the ESPP, eligible employees may purchase shares of Taysha common stock through payroll deductions at a price equal to 85% of the lower of the fair market values of the stock as of the beginning or the end of six-month offering periods. An employee’s payroll deductions under the ESPP are limited to 15% of the employee’s compensation and employees may not purchase more than 1,800 shares of Taysha common stock during any offering period. During the six months ended June 30, 2024 and 2023, stock-based compensation expense related to the ESPP was not material.

The following table summarizes the total stock-based compensation expense for the stock options, ESPP, RSAs and RSUs recorded in the condensed consolidated statements of operations for the three and six months ended June 30, 2024 and 2023 (in thousands):


	For the Three Months Ended June 30,				For the Six Months Ended June 30,
	2024		2023		2024		2023
Research and development expense	$	1,330	$	1,082	$	2,604	$	819
General and administrative expense		2,002		1,140		3,926		3,078
Total	$	3,332	$	2,222	$	6,530	$	3,897

Term Loans (Tables)

6 Months Ended

Jun. 30, 2024

Debt Disclosure [Abstract]

Schedule of Reconcile of Change in Fair Value of Debt

The following table reconciles the change in fair value of the Trinity Term Loans during the six months ended June 30, 2024 (in thousands):


Trinity Term Loans
Beginning fair value balance at January 1, 2024	$	40,508
Principal payments		—
Change in fair value reported in statements of operations		(268	)
Change in fair value reported in comprehensive loss		(2,405	)
Ending fair value balance as of June 30, 2024	$	37,835

The following table reconciles the change in fair value of the Success Fee liability during the six months ended June 30, 2024 (in thousands):


Success Fee
Beginning fair value balance at January 1, 2024	$	800
Change in fair value of Success Fee		—
Ending fair value balance as of June 30, 2024	$	800

Schedule of Future Principal Debt Payments on Term Loan Agreement

Future principal debt payments on the Trinity Term Loan Agreement as of June 30, 2024 are as follows (in thousands):


Year Ending December 31,
2024	$	—
2025		—
2026		—
2027		18,709
2028		21,291
Total principal payments	$	40,000

Summary of Significant Accounting Policies (Policies)	6 Months Ended
Summary of Significant Accounting Policies (Policies)	Jun. 30, 2024
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States (“GAAP”) as determined by the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X and are consistent in all material respects with those included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023, filed with the Securities and Exchange Commission (“SEC”) on March 19, 2024 (the “2023 Annual Report”). In the opinion of management, the unaudited condensed consolidated financial statements reflect all adjustments, which include only normal recurring adjustments necessary for the fair statement of the balances and results for the periods presented. The condensed consolidated balance sheet as of December 31, 2023 is derived from audited financial statements, however, it does not include all of the information and footnotes required by GAAP for complete financial statements. These unaudited condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and related notes in the Company’s 2023 Annual Report.
Principles of Consolidation	Principles of Consolidation The accompanying interim condensed consolidated financial statements include the accounts of Taysha and its wholly owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. The most significant estimates and assumptions in the Company’s financial statements relate to the determination of the fair value of the common stock prior to the initial public offering (“IPO”) (as an input into stock-based compensation), estimating manufacturing accruals and accrued or prepaid research and development expenses, the measurement of impairment of long-lived assets, the valuation of the Trinity Term Loans that are carried at fair value and the allocation of consideration received in connection with the Astellas Transactions (as defined below). These estimates and assumptions are based on current facts, historical experience and various other factors believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities and the recording of expenses that are not readily apparent from other sources. Actual results may differ materially from these estimates. To the extent there are material differences between the estimates and actual results, the Company’s future results of operations will be affected.
Significant Accounting Policies	Significant Accounting Policies There have been no changes in the Company’s significant accounting policies as disclosed in Note 2 to the audited consolidated financial statements included in the 2023 Annual Report.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements There have been no significant changes in recently adopted accounting pronouncements from those disclosed in the section titled “Financial Statements and Supplementary Data” included in the 2023 Annual Report.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting – Improvements to Reportable Segment Disclosures, to improve segment disclosure requirements under ASC 280, Segment Reporting, through enhancing disclosures about significant segment expenses. The guidance requires entities to provide significant segment expenses that are regularly provided to the chief operating decision maker and other segment expenses included in each reported measure of segment profitability. The ASU also enhances interim segment reporting requirements by aligning interim disclosures with information that must be disclosed annually in accordance with ASC 280. The guidance is effective for annual periods beginning after December 15, 2023, and interim periods beginning after December 15, 2024, applied retrospectively with early adoption permitted. The Company is still evaluating the impact this ASU will have on its consolidated financial statements and related disclosures.

Stock-Based Compensation - Additional Information (Details) - USD ($)			1 Months Ended			3 Months Ended		6 Months Ended		12 Months Ended
	Feb. 28, 2023	Sep. 16, 2020	May 31, 2023	Feb. 28, 2023	Feb. 28, 2022	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023	Jan. 01, 2024	Jan. 01, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options were exercised during the period						$ 2,000		$ 2,000
Percentage of common stock price purchased through payroll deductions					85.00%
Percentage of payroll deductions of employee's compensation during offering period					15.00%
Maximum number of shares employees may purchase during offering period					1,800
Stock-based compensation expense						$ 3,332,000	$ 2,222,000	$ 6,530,000	$ 3,897,000
Employee Stock Purchase Plan (ESPP)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance		724,000									724,000	632,075
Share-based payment award, expiration period		10 years
Share-based payment award, expiration date		Jan. 01, 2030
Percentage of automatic increase every year in common stock shares reserved for future issuance		1.00%
Share-based payment award, terms of award issuance								the number of shares of common stock that are automatically added on January 1st of each year for a period of up to ten years, commencing on the first January 1 following the IPO and ending on (and including) January 1, 2030, in an amount equal to the lesser of (i) one percent (1.0%) of the total number of shares of capital stock outstanding on December 31st of the preceding calendar year, and (ii) 724,000 shares of common stock.
Number of shares of common stock issued under ESPP		0						188,193
Employee Stock Purchase Plan (ESPP) \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized for issuance		362,000
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based payment award, compensation cost not yet recognized, weighted-average period of recognition								3 years 2 months 12 days
Share-based payment award, RSU/RSA granted								4,497,141
Outstsanding performance and market-based RSU's and RSAs						4,631,935		4,631,935		375,044
Share-based payment award, unvested RSU/RSA granted, compensation cost not yet recognized						$ 7,600,000		$ 7,600,000
Share-based payment award, RSU/RSA granted, weighted average grant date fair value								$ 1.83
Restricted stock units, performance and market-based restricted stock units of other option vested during period								240,250
Vested, weighted average grant date fair value								$ 4.96
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based payment award, options granted								9,220,821
Options forfeited								534,893
Share-based payment award, options granted, exercise price per share								$ 1.96
Share-based payment award, options, compensation cost not yet recognized						$ 16,900,000		$ 16,900,000
Share-based payment award, compensation cost not yet recognized, weighted-average period of recognition								2 years 8 months 12 days
Outstanding performance and market-based options						14,576,087		14,576,087		5,960,922
Unsettled RSU Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted stock units, performance and market-based restricted stock units of other option vested during period								222,216
Vested, weighted average grant date fair value								$ 5.25
Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares of common stock issued under ESPP								46,800	35,920
New Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance											9,348,009
Share-based payment award, expiration period		10 years
Share-based payment award, commencement date		Jan. 01, 2021
Share-based payment award, expiration date		Jan. 01, 2030
Percentage of automatic increase every year in common stock shares reserved for future issuance		5.00%
Share-based payment award, terms of award issuance								The number of shares of common stock reserved for issuance under the New Plan automatically increases on January 1 of each year, for a period of ten years, from January 1, 2021, continuing through January 1, 2030, by 5% of the total number of shares of common stock outstanding on December 31 of the preceding calendar year, or a lesser number of shares as may be determined by the Company’s board of directors.
New Plan \| Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period								4 years
Share-based payment award, RSU/RSA granted								4,497,141
New Plan \| Performance and Market-based Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based payment award, RSU/RSA granted				81,233				0
Performance and market-based restricted stock units of other option forfeited during period										46,562
Outstsanding performance and market-based RSU's and RSAs						0		0
Restricted stock units, performance and market-based restricted stock units of other option vested during period										34,671
New Plan \| Market-based Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based payment award, options granted				70,233
Options forfeited										70,233
New Plan \| Performance Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based payment award, options granted	70,235
Stock options were exercised during the period								$ 0
Outstanding performance and market-based options						58,346		58,346
Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance						4,000,000		4,000,000
Original Options \| Performance Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based payment award, options granted			2,166,653
Award vesting period			3 years 7 months 6 days
Share-based payment award, options, weighted-average grant date fair value			$ 0.5
Stock-based compensation expense			$ 0
Modified Options \| Performance Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based payment award, options granted										1,516,655
Award vesting period								3 years
Share-based payment award, options, weighted-average grant date fair value										$ 1.28
Share-based payment award, options, compensation cost not yet recognized						$ 1,300,000		$ 1,300,000
Share-based payment award, compensation cost not yet recognized, weighted-average period of recognition								1 year 8 months 12 days
Stock options were exercised during the period								$ 0
Stock-based compensation expense						$ 300,000		$ 600,000
Outstanding performance and market-based options						1,516,655		1,516,655
New Plan and Inducement Plan \| Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based payment award, expiration period						10 years		10 years
Share-based payment award, options granted						1,421,760		9,220,821
Award vesting period						4 years		4 years
Share-based payment award, options, weighted-average grant date fair value						$ 2.25		$ 1.49

Leases - Supplemental Information Related to Remaining Lease Term and Discount Rate (Details)	Jun. 30, 2024	Dec. 31, 2023
Leases [Abstract]
Weighted average remaining lease term (in years) - Finance leases	2 years 4 months 17 days	2 years 10 months 17 days
Weighted average remaining lease term (in years) - Operating leases	10 years 4 months 9 days	10 years 9 months
Weighted average discount rate - Finance leases	10.53%	10.52%
Weighted average discount rate - Operating leases	7.82%	7.80%

Balance Sheet Components - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Balance Sheet Related Disclosures [Abstract]
Prepaid research and development	$ 1,502	$ 1,412
Prepaid clinical trial	674	802
Deferred offering costs	601	681
Prepaid insurance	165	292
Prepaid bonus	130
Other	206	292
Total prepaid expenses and other current assets	$ 3,278	$ 3,479

Research, Collaboration and License Agreements - Additional Information (Details)	1 Months Ended					3 Months Ended		6 Months Ended		12 Months Ended
	Mar. 31, 2022 USD ($)	Mar. 31, 2021 USD ($)	Oct. 31, 2020 USD ($)	Aug. 31, 2020 USD ($)	Apr. 30, 2020 USD ($) Product	Jun. 30, 2024 USD ($) shares	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($) shares	Jun. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) shares	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Oct. 29, 2020 USD ($)	Feb. 21, 2020 USD ($)	Nov. 30, 2019 shares
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Common stock, shares issued \| shares						201,381,450		201,381,450		186,960,193
Research and development						$ 15,073,000	$ 19,791,000	$ 35,730,000	$ 32,305,000
TSHA-120
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Additional milestone payments								0
Upfront Payment		$ 5,500,000
License Agreement for CLN7
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Additional milestone payments								0
Payment of one-time upfront license fee	$ 300,000
License agreement regulatory related milestones maximum amount payable	7,700,000
License agreement sales-related milestones maximum amount payable	$ 7,500,000
UT Southwestern Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Preclinical activities period under sponsored research agreements					2 years
Minimum licensed product to develop obtain regulatory approval for and commercialize \| Product					1
Common stock, shares issued \| shares															2,179,000
Percentage of fully diluted common stock shares outstanding															20.00%
Queens Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Additional milestone payments								0
Queens Agreement \| Research and Development Expense
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Cash payment to acquire license agreement					$ 3,000,000
Queens Agreement \| Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
License agreement regulatory milestones payment														$ 10,000,000
License agreement commercial milestones payment														$ 10,000,000
Abeona CLN1 Agreements
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Additional milestone payments								0
License fee payment				$ 3,000,000
Purchase of clinical materials and reimbursement incurred development costs			$ 4,000,000
Research and development											$ 3,000,000	$ 7,000,000
Abeona CLN1 Agreements \| Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
License and inventory purchase agreement regulatory related milestones payment				26,000,000
License and inventory purchase agreement sales related milestones payment				$ 30,000,000
Abeona \| Abeona Rett Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Additional milestone payments								0
Research and development								$ 1,000,000.0		$ 3,500,000
Payment of one-time upfront license fee												$ 3,000,000
Abeona \| Maximum \| Abeona Rett Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Regulatory related milestones obligation payable													$ 26,500,000
Sale-related milestones per licensed product and royalties on net sales of licensed products payable													$ 30,000,000

Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2024

Fair Value Disclosures [Abstract]

Schedule of Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis


	June 30, 2024
	Total		Level 1		Level 2		Level 3
Assets:
Cash equivalents – money market funds	$	172,103	$	172,103	$	—	$	—
Total assets	$	172,103	$	172,103	$	—	$	—
Liabilities:
Trinity Term Loans	$	37,835	$	—	$	—	$	37,835
Success Fee Derivative liability		800		—		—		800
SSI Warrant liability		596		—		—		596
Total liabilities	$	39,231	$	—	$	—	$	39,231


	December 31, 2023
	Total		Level 1		Level 2		Level 3
Assets:
Cash equivalents – money market funds	$	142,425	$	142,425	$	—	$	—
Total assets	$	142,425	$	142,425	$	—	$	—
Liabilities:
Trinity Term Loans	$	40,508	$	—	$	—	$	40,508
Success Fee Derivative liability		800		—		—		800
SSI Warrant liability		454		—		—		454
Total liabilities	$	41,762	$	—	$	—	$	41,762

Term Loans - Schedule of Future Principal Debt Payments on Term Loan Agreement (Details) $ in Thousands	Jun. 30, 2024 USD ($)
Debt Disclosure [Abstract]
2027	$ 18,709
2028	21,291
Total principal payments	$ 40,000

Astellas Agreements (Tables)

6 Months Ended

Jun. 30, 2024

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Summary of Allocation for Transaction Price to the Three Performance Obligations

The following table summarizes the allocation of the transaction price to the three performance obligations at contract inception (amounts in thousands):


	Transaction Price Allocation
Option to obtain license for Rett	$	5,485
Option to obtain license for GAN		2,317
Rett research and development activities		28,257
Total	$	36,059

Net Loss Per Common Share - Schedule of Calculation of Basic and Diluted Net Loss Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Earnings Per Share [Abstract]
Net loss	$ (20,928)	$ (24,598)	$ (44,989)	$ (42,220)
Weighted average common shares outstanding, basic	232,821,553	64,244,531	232,035,448	63,755,435
Weighted average common shares outstanding, diluted	232,821,553	64,244,531	232,035,448	63,755,435
Net loss per common share, basic	$ (0.09)	$ (0.38)	$ (0.19)	$ (0.66)
Net loss per common share, diluted	$ (0.09)	$ (0.38)	$ (0.19)	$ (0.66)

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-3

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482635/260-10-55-15

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (e)(4)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-7

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-2

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 60B
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-60B

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-4

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482662/260-10-50-1

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-10

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(25))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(27))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(23))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483586/944-220-S99-1

Reference 16: http://www.xbrl.org/2003/role/exampleRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 52
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482635/260-10-55-52

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-7

+ Details

- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-3

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482635/260-10-55-15

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (e)(4)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-7

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-2

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 60B
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-60B

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-4

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482662/260-10-50-1

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(25))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(27))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(23))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483586/944-220-S99-1

Reference 15: http://www.xbrl.org/2003/role/exampleRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 52
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482635/260-10-55-52

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-7

+ Details

- Definition

Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities; of income (loss) available to common shareholders.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-3

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-4

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 5
-Subparagraph (SAB Topic 6.B)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483621/220-10-S99-5

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482662/260-10-50-1

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 30
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-30

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-10

Reference 11: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 31
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-31

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 11
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-11

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 60B
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-60B

+ Details

Net Loss Per Common Share (Tables)

6 Months Ended

Jun. 30, 2024

Earnings Per Share [Abstract]

Schedule of Calculation of Basic and Diluted Net Loss Per Common Share

The following table represents the calculation of basic and diluted net loss per common share (in thousands, except share and per share data):


	For the Three Months Ended June 30,						For the Six Months Ended June 30,
	2024			2023			2024			2023
Net loss	$	(20,928	)	$	(24,598	)	$	(44,989	)	$	(42,220	)
Weighted-average shares of common stock outstanding used to compute net loss per common share, basic and diluted		232,821,553			64,244,531			232,035,448			63,755,435
Net loss per common share, basic and diluted	$	(0.09	)	$	(0.38	)	$	(0.19	)	$	(0.66	)

Schedule of Common Stock Equivalents Outstanding Excluded from Computation of Diluted Net Loss Per Share Attributable to Common Stockholders

The following common stock equivalents outstanding as of June 30, 2024 and 2023 were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because including them would have been anti‑dilutive:


	June 30, 2024		June 30, 2023
Unvested RSUs		4,631,935		492,497
Stock options		16,151,088		8,251,952
SSI Warrants		316,667		525,000
Total		21,099,690		9,269,449

Balance Sheet Components (Tables)

6 Months Ended

Jun. 30, 2024

Balance Sheet Related Disclosures [Abstract]

Schedule of Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets consisted of the following (in thousands):


	June 30, 2024		December 31, 2023
Prepaid research and development	$	1,502	$	1,412
Prepaid clinical trial		674		802
Deferred offering costs		601		681
Prepaid insurance		165		292
Prepaid bonus		130		—
Other		206		292
Total prepaid expenses and other current assets	$	3,278	$	3,479

Schedule of Property Plant and Equipment Net

Property, plant and equipment, net consisted of the following (in thousands):


	June 30, 2024			December 31, 2023
Leasehold improvements	$	2,117		$	2,117
Laboratory equipment		3,008			2,868
Computer equipment		1,271			1,133
Furniture and fixtures		864			864
Construction in progress		6,882			6,823
		14,142			13,805
Accumulated depreciation		(3,629	)		(2,979	)
Property, plant and equipment, net	$	10,513		$	10,826

Schedule of Accrued Expense and Other Current Labilities

Accrued expenses and other current liabilities consisted of the following (in thousands):


	June 30, 2024		December 31, 2023
Accrued research and development	$	2,613	$	3,467
Accrued compensation		2,885		3,423
Accrued clinical trial		2,178		1,851
Lease liabilities, current portion		1,754		1,646
Accrued professional and consulting fees		1,072		330
Warrant liability		596		454
Accrued severance		—		390
Other		777		723
Total accrued expenses and other current liabilities	$	11,875	$	12,284

Strategic Reprioritization

6 Months Ended

Jun. 30, 2024

Restructuring and Related Activities [Abstract]

Strategic Reprioritization

Note 14 – Strategic Reprioritization

In March 2022, the Company implemented changes to the Company’s organizational structure as well as a broader operational cost reduction plan to enable the Company to focus on specific clinical-stage programs for GAN and Rett syndrome. Substantially all other research and development activities have been paused to increase operational efficiency.

In connection with prioritization of programs, the Company reduced headcount by approximately 35% across all functions in March 2022. In accordance with ASC 420, Exit and Disposal Activities, the Company recorded one-time severance and termination-related costs of $2.6 million in the condensed consolidated statements of operations for the three months ended March 31, 2022, primarily within research and development expenses. In December 2022 and throughout the first quarter of 2023, the Company further reduced headcount and recorded additional one-time severance and termination related costs of $2.7 million within research and development and general and administrative expenses.

Payment of these costs are complete as of June 30, 2024. The amount of accrued severance recorded as of June 30, 2024 is as follows (amounts in thousands):


	Accrued Severance
Accrued severance as of January 1, 2024	$	390
Severance recorded		—
Severance paid		(390	)
Accrued severance as of June 30, 2024	$	—

Subsequent Events

6 Months Ended

Jun. 30, 2024

Subsequent Events [Abstract]

Subsequent Events

Note 16 – Subsequent Events

On June 26, 2024, the Company entered into the June 2024 Underwriting Agreement with the Underwriters to issue and sell 14,361,113 shares of common stock and pre-funded warrants to purchase 18,972,221 shares of its common stock in the June 2024 Offering pursuant to an effective shelf registration statement on Form S-3 and a related prospectus and prospectus supplement. The Underwriters purchased the shares and the pre-funded warrants from the Company pursuant to the June 2024 Underwriting Agreement at a price of $2.115 per share and $2.114 per pre-funded warrant, respectively. The closing of the June 2024 Offering occurred on June 27, 2027. See Note 1 for additional information. On July 9, 2024, the Underwriters exercised their option to purchase an additional 3,235,000 shares of common stock pursuant to the June 2024 Underwriting Agreement. The Company received additional net proceeds of $6.8 million after deducting underwriting discounts and commissions.

Condensed Consolidated Statements of Stockholders' (Deficit) Equity - USD ($) $ in Thousands	Total	Private Placement	Underwritten Public Offering	Common Stock	Common Stock Private Placement	Common Stock Underwritten Public Offering	Additional Paid-in Capital	Additional Paid-in Capital Private Placement	Additional Paid-in Capital Underwritten Public Offering	Accumulated Deficit	Accumulated Other Comprehensive Loss
Balance at Dec. 31, 2022	$ 949			$ 1			$ 402,389			$ (401,441)
Balance, shares at Dec. 31, 2022				63,207,507
Stock-based compensation	3,897						3,897
Issuance of common stock		$ 210						$ 210
Issuance of common stock, shares					705,218
Issuance of common stock, upon vesting and settlement of restricted stock units, net, shares				483,992
Issuance of common stock under ESPP	50						50
Issuance of common stock under ESPP, shares				35,920
Net loss	(42,220)									(42,220)
Balance at Jun. 30, 2023	(37,114)			$ 1			406,546			(443,661)
Balance, shares at Jun. 30, 2023				64,432,637
Balance at Mar. 31, 2023	(14,948)			$ 1			404,114			(419,063)
Balance, shares at Mar. 31, 2023				63,473,349
Stock-based compensation	2,222						2,222
Issuance of common stock		$ 210						$ 210
Issuance of common stock, shares					705,218
Issuance of common stock, upon vesting and settlement of restricted stock units, net, shares				254,070
Net loss	(24,598)									(24,598)
Balance at Jun. 30, 2023	(37,114)			$ 1			406,546			(443,661)
Balance, shares at Jun. 30, 2023				64,432,637
Balance at Dec. 31, 2023	$ 74,937			$ 2			587,942			(513,007)
Balance, shares at Dec. 31, 2023	186,960,193			186,960,193
Stock-based compensation	$ 6,530						6,530
Issuance of common stock			$ 69,957						$ 69,957
Issuance of common stock, shares						14,361,113
Issuance of common stock, upon vesting and settlement of restricted stock units, net, shares				11,282
Issuance of common stock under ESPP	26						26
Issuance of common stock under ESPP, shares				46,800
Issuance of common stock upon exercise of stock options, net	2						2
Issuance of common stock upon exercise of stock options, net, Shares				2,062
Gain (loss) on instrument specific credit risk	2,405										$ 2,405
Net loss	(44,989)									(44,989)
Balance at Jun. 30, 2024	$ 108,868			$ 2			664,457			(557,996)	2,405
Balance, shares at Jun. 30, 2024	201,381,450			201,381,450
Balance at Mar. 31, 2024	$ 53,849			$ 2			591,166			(537,068)	(251)
Balance, shares at Mar. 31, 2024				187,018,275
Stock-based compensation	3,332						3,332
Issuance of common stock			$ 69,957						$ 69,957
Issuance of common stock, shares						14,361,113
Issuance of common stock upon exercise of stock options, net	2						2
Issuance of common stock upon exercise of stock options, net, Shares				2,062
Gain (loss) on instrument specific credit risk	2,656										2,656
Net loss	(20,928)									(20,928)
Balance at Jun. 30, 2024	$ 108,868			$ 2			$ 664,457			$ (557,996)	$ 2,405
Balance, shares at Jun. 30, 2024	201,381,450			201,381,450

Subsequent Events - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	Jul. 09, 2024	Jul. 09, 2024	Jun. 30, 2024	Jun. 26, 2024	Dec. 31, 2023
Subsequent Event [Line Items]
Common stock, shares issued			201,381,450		186,960,193
Underwriting Agreement
Subsequent Event [Line Items]
Common stock, shares issued				14,361,113
Underwriter agreed to purchase share price of per share				$ 2.115
Option to purchase additional number of common shares				5,000,000
Underwriting Agreement \| Subsequent Event
Subsequent Event [Line Items]
Option to purchase additional number of common shares	3,235,000	3,235,000
Net proceeds from issuance of common stock	$ 6.8	$ 76.8
Underwriting Agreement \| Common Stock
Subsequent Event [Line Items]
Underwriter agreed to purchase share price of per share				$ 2.115
Underwriting Agreement \| Pre-Funded Warrants
Subsequent Event [Line Items]
Warrants issued				18,972,221
Underwriter agreed to purchase share price of per share				$ 2.114

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Jun. 30, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Preferred stock, par value per share	$ 0.00001	$ 0.00001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value per share	$ 0.00001	$ 0.00001
Common stock, shares authorized	400,000,000	400,000,000
Common stock, shares issued	201,381,450	186,960,193
Common stock, shares outstanding	201,381,450	186,960,193

Net Loss Per Common Share

6 Months Ended

Jun. 30, 2024

Earnings Per Share [Abstract]

Net Loss Per Common Share

Note 11—Net Loss Per Common Share

Basic net loss per common share is computed by dividing net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding for the period. Since the Company had a net loss in all periods presented, basic and diluted net loss per common share are the same.

In August 2023, the Company issued liability-classified the 2023 Pre-Funded Warrants with a nominal exercise price of $0.001 per share, which were subsequently reclassified into equity in November 2023 after conditions for exercise were met. In June 2024, the Company issued the June 2024 Pre-Funded Warrants with a nominal exercise price of $0.001 per share. See Note 10 for more information. In accordance with ASC 260, Earnings Per Share, shares issuable for little to no cash consideration should be included in the number of outstanding shares used to calculate basic loss per share as long as all conditions necessary for exercise are met. The 2023 Pre-Funded Warrants and the June 2024 Pre-Funded Warrants are therefore included as outstanding shares as of June 30, 2024 to calculate the weighted average number of shares outstanding to calculate basic loss per share.

The following table represents the calculation of basic and diluted net loss per common share (in thousands, except share and per share data):


	For the Three Months Ended June 30,						For the Six Months Ended June 30,
	2024			2023			2024			2023
Net loss	$	(20,928	)	$	(24,598	)	$	(44,989	)	$	(42,220	)
Weighted-average shares of common stock outstanding used to compute net loss per common share, basic and diluted		232,821,553			64,244,531			232,035,448			63,755,435
Net loss per common share, basic and diluted	$	(0.09	)	$	(0.38	)	$	(0.19	)	$	(0.66	)


	June 30, 2024		June 30, 2023
Unvested RSUs		4,631,935		492,497
Stock options		16,151,088		8,251,952
SSI Warrants		316,667		525,000
Total		21,099,690		9,269,449

Term Loans

6 Months Ended

Jun. 30, 2024

Debt Disclosure [Abstract]

Term Loans

Note 7 – Term Loans

Loan with Trinity Capital

On November 13, 2023 (the “Trinity Closing Date”), the Company entered into a Loan and Security Agreement (the “Trinity Term Loan Agreement”), by and among the Company, the lenders party thereto from time to time (the “Trinity Lenders”) and Trinity Capital Inc., as administrative agent and collateral agent for the Trinity Lenders (“Trinity”). The Trinity Term Loan Agreement provides for, on the Trinity Closing Date, $40.0 million aggregate principal amount of term loans (collectively, the “Trinity Term Loans”). The Company drew the Trinity Term Loans in full on the Trinity Closing Date.

The interest rate applicable to the Trinity Term Loans is the greater of (a) the Wall Street Journal (“WSJ”) Prime Rate plus 4.50% or (b) 12.75% per annum. The Trinity Term Loans are interest only from the Trinity Closing Date through 36 months from the Trinity Closing Date, which may be extended to 48 months from the Trinity Closing Date upon the satisfaction of certain milestones set forth in the Trinity Term Loan Agreement, after which the Company is required to pay equal monthly installments of principal

through November 13, 2028 (the “Maturity Date”). As of June 30, 2024, $40.0 million was outstanding on the Term Loan, recorded as Term Loan, net on the condensed consolidated balance sheet.

Future principal debt payments on the Trinity Term Loan Agreement as of June 30, 2024 are as follows (in thousands):


Year Ending December 31,
2024	$	—
2025		—
2026		—
2027		18,709
2028		21,291
Total principal payments	$	40,000

The Trinity Term Loans may be prepaid in full (i) from the Trinity Closing Date through November 13, 2024, with payment of a 3.00% prepayment premium, (ii) from November 13, 2024 through November 13, 2025, with payment of a 2.00% prepayment premium, and (iii) from November 13, 2025 through, but excluding, the Maturity Date, with payment of a 1.00% prepayment premium. On the Trinity Closing Date, the Company paid to Trinity a commitment fee of 1.00% of the original principal amount of the Trinity Term Loans. Upon repayment in full of the Trinity Term Loans, the Company will pay to Trinity an end of term payment equal to 5.00% of the original principal amount of the Trinity Term Loans.

The obligations under the Trinity Term Loan Agreement are secured by a perfected security interest in all of the Company’s assets except for certain customarily excluded property pursuant to the terms of the Trinity Term Loan Agreement. There are no financial covenants and no warrants associated with the Trinity Term Loan Agreement. The Trinity Term Loan Agreement contains various covenants that limit the Company’s ability to engage in specified types of transactions without the consent of Trinity and the Trinity Lenders which include, among others, incurring or assuming certain debt; merging, consolidating or acquiring all or substantially all of the capital stock or property of another entity; changing the nature of the Company’s business; changing the Company’s organizational structure or type; licensing, transferring or disposing of certain assets; granting certain types of liens on the Company’s assets; making certain investments; and paying cash dividends. As of June 30, 2024, the Company is in compliance with all covenants of the Trinity Term Loans.

The Trinity Term Loan Agreement also contains customary representations and warranties, and also includes customary events of default, including payment default, breach of covenants, change of control, and material adverse effects. Upon the occurrence of an event of default, a default interest rate of an additional 5.00% per annum may be applied to the outstanding loan balances, and the Trinity Lenders may declare all outstanding obligations immediately due and payable and exercise all of its rights and remedies as set forth in the Trinity Term Loan Agreement and under applicable law.

The proceeds of the Trinity Term Loans were used to repay the Company’s obligations under the Term Loan Agreement (as defined below) with Silicon Valley Bank in full. The Term Loan Agreement with Silicon Valley Bank was terminated concurrently with entry into the Trinity Term Loan Agreement.

The Company assessed the terms and features of the Trinity Term Loans and determined that the Company was eligible to elect the fair value option under ASC 825, Financial Instruments. The Trinity Term Loans contain various embedded features and the election of the fair value option allowed the Company to bypass analysis of potential embedded derivatives and further analysis of bifurcation of any recognized financial liabilities. Under the fair value option, the financial liability is initially measured at its fair value on the issue date and subsequently remeasured at estimated fair value on a recurring basis at each reporting date. Changes in the fair value of the Trinity Term Loans, which include accrued interest, if any, are recorded as a component of other expense (income) in the condensed consolidated statements of operations. The Company has not elected to present interest expense separately from changes in fair value and therefore will not present interest expense associated with the Trinity Term Loans. Any changes in fair value caused by instrument-specific credit risk are presented separately in other comprehensive income or loss if material. Under the fair value option, debt issuance costs are expensed as incurred. The Company incurred $0.9 million of debt issuance costs, which were recorded within general and administrative expense in the consolidated statements of operations for the year ended December 31, 2023.

In connection with the Trinity Term Loans, the Company entered into a Success Fee Agreement with Trinity which specifies the terms regarding a fee in the amount of 10% of the principal amount of the funded Trinity Term Loans (the "Success Fee"). The Success Fee is payable upon the achievement of certain corporate development value-inflection milestones. The Success Fee survives the termination of the Trinity Term Loans and expires on the earlier of ten years, or payment in full in cash of the Success Fee. The Company determined that the Success Fee represents a freestanding financial instrument and should be accounted for as a derivative

liability under ASC 815 and recorded a liability within other non-current liabilities on the consolidated balance sheet, at fair value on the Trinity Closing Date and will be marked-to-market at the end of each reporting period with gains and losses recognized as a component of other income (expense) in the condensed consolidated statements of operations.

The proceeds from the Trinity Term Loans were allocated to the Success Fee and Trinity Term Loans based on their respective fair values on the Trinity Closing Date. The fair values were determined utilizing a probability-weighted income approach, including variables for the timing of a success event and other probability estimates.

The Company determined the fair value of the Trinity Term Loans and the Success Fee using a probability-weighted income approach and recorded the loan at fair value of $39.2 million and the Success Fee liability at fair value of $0.8 million in the condensed consolidated balance sheet at issuance. The Company calculated the discounted cash flows of the Trinity Term Loans using a discount rate of 15.68% and adjusted for the probability of various repayment scenarios. The Company calculated the discounted cash flows of the Success Fee liability, using a discount rate of 15.68% then adjusted for the probability of achievement of certain corporate development value-inflection milestones.

The Company remeasured the fair value of the Trinity Term Loans and Success Fee as of June 30, 2024 using a probability-weighted income approach. The Company calculated discounted cash flows of the Trinity Term Loans using a discount rate of 18.22% and adjusted for the probability of various repayment scenarios. The Company calculated the discounted cash flows of the Success Fee liability, using a discount rate of 18.22% then adjusted for the probability of achievement of certain corporate development value-inflection milestones.

The following table reconciles the change in fair value of the Trinity Term Loans during the six months ended June 30, 2024 (in thousands):


Trinity Term Loans
Beginning fair value balance at January 1, 2024	$	40,508
Principal payments		—
Change in fair value reported in statements of operations		(268	)
Change in fair value reported in comprehensive loss		(2,405	)
Ending fair value balance as of June 30, 2024	$	37,835

During the three and six months ended June 30, 2024, the Company recorded $1.3 million and $2.6 million, respectively, of interest expense within change in fair value of term loans, all of which was paid as of June 30, 2024.

The following table reconciles the change in fair value of the Success Fee liability during the six months ended June 30, 2024 (in thousands):


Success Fee
Beginning fair value balance at January 1, 2024	$	800
Change in fair value of Success Fee		—
Ending fair value balance as of June 30, 2024	$	800

Loan with Silicon Valley Bank

On August 12, 2021 (the “SVB Closing Date”), the Company entered into a Loan and Security Agreement (the “Term Loan Agreement”), by and among the Company, the lenders party thereto from time to time (the “Lenders”) and Silicon Valley Bank, as administrative agent and collateral agent for the Lenders (“Agent”). The Term Loan Agreement provided for (i) on the SVB Closing Date, $40.0 million aggregate principal amount of term loans available through December 31, 2021, (ii) from January 1, 2022 until September 30, 2022, an additional $20.0 million term loan facility available at the Company’s option upon having three distinct and active clinical stage programs, determined at the discretion of the Agent, at the time of draw, (iii) from October 1, 2022 until March 31, 2023, an additional $20.0 million term loan facility available at the Company’s option upon having three distinct and active clinical stage programs, determined at the discretion of the Agent, at the time of draw and (iv) from April 1, 2023 until December 31, 2023, an additional $20.0 million term loan facility available upon approval by the Agent and the Lenders (collectively, the “Term Loans”). The Company drew $30.0 million in term loans on the SVB Closing Date and $10.0 million in term loans in December 2021. The Company did not draw on the two additional $20.0 million tranches prior to expiration on September 30, 2022 and March 31,

2023. The Term Loan Agreement with Silicon Valley Bank was terminated concurrently with entry into the Trinity Term Loan Agreement in November 2023.

The interest rate applicable to the Term Loans was the greater of (a) the WSJ Prime Rate plus 3.75% or (b) 7.00% per annum. The Term Loans were interest only from the SVB Closing Date through August 31, 2024, after which the Company was required to pay equal monthly installments of principal through August 1, 2026, the maturity date.

The Term Loans could have been prepaid in full through August 12, 2023, with payment of a 1.00% prepayment premium, after which they could be prepaid in full with no prepayment premium. An additional final payment of 7.50% of the amount of Terms Loans advanced by the Lenders (“Exit Fee”) was due upon prepayment or repayment of the Term Loans in full. The Exit Fee of $3.0 million was recorded as debt discount. The debt discount was being accreted using the effective interest method over the term of the Term Loans within interest expense in the condensed consolidated statements of operations.

The obligations under the Term Loan Agreement were secured by a perfected security interest in all of the Company’s assets except for intellectual property and certain other customarily excluded property pursuant to the terms of the Term Loan Agreement.

Upon termination of the Term Loan Agreement with Silicon Valley Bank, the Company made a prepayment of $43.2 million to satisfy the Company’s principal and interest obligations and related fees under the Term Loan Agreement. The payoff amount paid by the Company in connection with the Term Loans included payment of the Exit Fee of $3.0 million and accrued interest of $0.2 million. In connection with the repayment of the Term Loans, the remaining balance of debt discount of $1.4 million was recognized as a component of other income (expense) in the condensed consolidated statements of operations for the year ended December 31, 2023.

During the three and six months ended June 30, 2023, the Company recognized interest expense related to the Term Loan of $1.4 million and $2.7 million, respectively.

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (h)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(c))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 470
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//470/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1C
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1C

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1C
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1C

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1C
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1C

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1E
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1E

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

+ Details

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 172,743	$ 143,940
Restricted cash	449	449
Prepaid expenses and other current assets	3,278	3,479
Assets held for sale	2,000	2,000
Total current assets	178,470	149,868
Restricted cash	2,151	2,151
Property, plant and equipment, net	10,513	10,826
Operating lease right-of-use assets	8,971	9,582
Other non-current assets	288	304
Total assets	200,393	172,731
Current liabilities
Accounts payable	8,718	6,366
Accrued expenses and other current liabilities	11,875	12,284
Deferred revenue	13,583	18,106
Total current liabilities	34,176	36,756
Term loan, net	37,835	40,508
Operating lease liability, net of current portion	18,134	18,953
Other non-current liabilities	1,380	1,577
Total liabilities	91,525	97,794
Commitments and contingencies - Note 13
Stockholders' (deficit) equity
Preferred stock, $0.00001 par value per share; 10,000,000 shares authorized and no shares issued and outstanding as of June 30, 2024 and December 31, 2023
Common stock, $0.00001 par value per share; 400,000,000 shares authorized and 201,381,450 and 186,960,193 issued and outstanding as of June 30, 2024 and December 31, 2023, respectively	2	2
Additional paid-in capital	664,457	587,942
Accumulated other comprehensive income	2,405
Accumulated deficit	(557,996)	(513,007)
Total stockholders' equity	108,868	74,937
Total liabilities and stockholders' equity	$ 200,393	$ 172,731

Term Loans - Schedule of Reconcile of Change in Fair Value of Debt (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2024
Debt Instrument [Line Items]
Change in fair value reported in comprehensive loss	$ (2,656)	$ (2,405)
Trinity Term Loans
Debt Instrument [Line Items]
Beginning fair value balance		40,508
Change in fair value		(268)
Change in fair value reported in comprehensive loss		(2,405)
Ending fair value balance	37,835	37,835
Success Fee Liability
Debt Instrument [Line Items]
Beginning fair value balance		800
Ending fair value balance	$ 800	$ 800

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482900/835-30-50-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(f))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04(a))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-3

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69B
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481568/470-20-55-69B

Reference 6: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69C
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481568/470-20-55-69C

Reference 7: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69E
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481568/470-20-55-69E

Reference 8: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69F
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481568/470-20-55-69F

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 11: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (h)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1D
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1D

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1D
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1D

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1D
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1D

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1E
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1E

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1E
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1E

Reference 20: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1E
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1E

Reference 21: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1F
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1F

Reference 22: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1F
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1F

Reference 23: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1F
-Subparagraph (b)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1F

Reference 24: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1F
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1F

Reference 25: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

+ Details

Stock-Based Compensation - Schedule of Restricted Stock Units Activity (Details) - Restricted Stock Units	6 Months Ended
	Jun. 30, 2024 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Nonvested, Number of Shares, Beginning Balance \| shares	375,044
Restricted units/stock granted, Number of Shares \| shares	4,497,141
Vested, Number of Shares \| shares	(240,250)
Nonvested, Number of Shares, Ending Balance \| shares	4,631,935
Nonvested, Weighted Average Grant Date Fair Value per Share, Beginning Balance \| $ / shares	$ 6.63
Restricted units/stock granted, Weighted Average Grant Date Fair Value per Share \| $ / shares	1.83
Vested, Weighted Average Grant Date Fair Value per Share \| $ / shares	4.96
Nonvested, Weighted Average Grant Date Fair Value per Share, Ending Balance \| $ / shares	$ 2.06

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

+ Details

Astellas Agreements - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended	3 Months Ended		6 Months Ended
	Oct. 21, 2022	Oct. 31, 2022	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Common stock, shares issued			201,381,450		201,381,450		186,960,193
Probability of option exercise		50.00%
Decrease in revenue previously recognized					$ 1,100
Revenues			$ 1,112	$ 2,395	4,523	$ 7,101
Deferred revenue			13,583		13,583		$ 18,106
Rett Option
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Deferred revenue			5,500		5,500		5,500
Rett research and development activities
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenues			1,100	$ 2,400	4,500	$ 7,100
Deferred revenue			$ 8,100		8,100		$ 12,600
Astellas
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront Payment	$ 20,000
Transaction price		$ 36,100			36,059
Deferred revenue		$ 36,100
Astellas \| Securities Purchase Agreement \| Private Placement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Common stock, shares issued	7,266,342	7,266,342
Aggregate gross proceeds	$ 30,000
Fair value of shares transferred, Value		$ 13,950
Share price		$ 1.92
Transaction price		$ 16,100
Difference of market value paid		$ 30,000
Astellas \| TSHA-120
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront Payment					20,000
Transaction price					36,100
Astellas \| TSHA-120 \| Private Placement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Transaction price					16,100
Astellas \| Rett research and development activities
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Transaction price					$ 28,257

Balance Sheet Components

6 Months Ended

Jun. 30, 2024

Balance Sheet Related Disclosures [Abstract]

Balance Sheet Components

Note 4—Balance Sheet Components

Prepaid expenses and other current assets consisted of the following (in thousands):


	June 30, 2024		December 31, 2023
Prepaid research and development	$	1,502	$	1,412
Prepaid clinical trial		674		802
Deferred offering costs		601		681
Prepaid insurance		165		292
Prepaid bonus		130		—
Other		206		292
Total prepaid expenses and other current assets	$	3,278	$	3,479

Property, plant and equipment, net consisted of the following (in thousands):


	June 30, 2024			December 31, 2023
Leasehold improvements	$	2,117		$	2,117
Laboratory equipment		3,008			2,868
Computer equipment		1,271			1,133
Furniture and fixtures		864			864
Construction in progress		6,882			6,823
		14,142			13,805
Accumulated depreciation		(3,629	)		(2,979	)
Property, plant and equipment, net	$	10,513		$	10,826

Property, plant and equipment, net includes $0.8 million and $1.0 million of assets capitalized as finance leases as of June 30, 2024 and December 31, 2023, respectively.

Depreciation expense was $0.3 million and $0.4 million for the three months ended June 30, 2024 and 2023, respectively. Depreciation expense was $0.6 million and $0.7 million for the six months ended June 30, 2024 and 2023, respectively.

Accrued expenses and other current liabilities consisted of the following (in thousands):


	June 30, 2024		December 31, 2023
Accrued research and development	$	2,613	$	3,467
Accrued compensation		2,885		3,423
Accrued clinical trial		2,178		1,851
Lease liabilities, current portion		1,754		1,646
Accrued professional and consulting fees		1,072		330
Warrant liability		596		454
Accrued severance		—		390
Other		777		723
Total accrued expenses and other current liabilities	$	11,875	$	12,284

Organization and Description of Business Operations

6 Months Ended

Jun. 30, 2024

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Organization and Description of Business Operations

Note 1—Organization and Description of Business Operations

Taysha Gene Therapies, Inc. (the “Company” or “Taysha”) was originally formed under the laws of the State of Texas on September 20, 2019. Taysha converted to a Delaware corporation on February 13, 2020, which had no impact to the Company’s par value or issued and authorized capital structure.

Taysha is a clinical-stage biotechnology company focused on advancing AAV-based gene therapies for severe monogenic diseases of the central nervous system.

Sales Agreement

On October 5, 2021, the Company entered into a Sales Agreement (the “Sales Agreement”) with SVB Securities LLC (f/k/a SVB Leerink LLC) and Wells Fargo Securities, LLC (collectively, the “Sales Agents”), pursuant to which the Company may issue and sell, from time to time in its sole discretion, shares of its common stock having an aggregate offering price of up to $150.0 million through the Sales Agents. In March 2022, the Company amended the Sales Agreement to, among other things, include Goldman Sachs & Co. LLC as an additional Sales Agent. The Sales Agents may sell common stock by any method permitted by law deemed to be an “at-the-market offering” as defined in Rule 415(a)(4) of the Securities Act, including sales made directly on or through the Nasdaq Global Select Market or any other existing trade market for the common stock, in negotiated transactions at market prices prevailing at the time of sale or at prices related to prevailing market prices, or any other method permitted by law. The Sales Agents are entitled to receive 3.0% of the gross sales price per share of common stock sold under the Sales Agreement. In April 2022, the Company sold 2,000,000 shares of common stock under the Sales Agreement and received $11.6 million in net proceeds. No other shares of common stock have been issued and sold pursuant to the Sales Agreement as of June 30, 2024.

Liquidity and Capital Resources

The Company has incurred operating losses since inception and expects to continue to incur significant operating losses for the foreseeable future and may never become profitable. Losses are expected to continue as the Company continues to invest in its research and development activities. As of June 30, 2024, the Company had an accumulated deficit of $558.0 million. The Company expects to continue to incur significant expenses and operating losses for the foreseeable future.

On June 26, 2024, the Company entered into an underwriting agreement (the “June 2024 Underwriting Agreement”) with Jefferies LLC and Goldman Sachs & Co. LLC, as representatives of the several underwriters set forth therein (collectively, the “Underwriters”), to issue and sell 14,361,113 shares of the Company’s common stock and, in lieu of common stock to certain investors, pre-funded warrants to purchase 18,972,221 shares of its common stock in an underwritten public offering (the “June 2024 Offering”), pursuant to an effective shelf registration statement on Form S-3 and a related prospectus and prospectus supplement. The offering price to the public was $2.25 per share of common stock and $2.249 per pre-funded warrant, which was the price to the public of each share of common stock sold in the June 2024 Offering minus the $0.001 exercise price per pre-funded warrant. The Underwriters purchased the shares and the pre-funded warrants from the Company pursuant to the June 2024 Underwriting Agreement at a price of $2.115 per share and $2.114 per pre-funded warrant, respectively. See Note 10 for additional information. The initial closing of the June 2024 Offering occurred on June 27, 2024. In addition, the Company granted the Underwriters an option to purchase, for a period of 30 days, up to an additional 5,000,000 shares of common stock. On July 9, 2024, the Underwriters exercised their option to purchase an additional 3,235,000 shares of common stock. The total net proceeds from the June 2024 Offering were approximately $76.8 million, including the proceeds from the Underwriter’s option, after deducting underwriting discounts and commissions and offering expenses. See Note 16 for additional information.

Future capital requirements will depend on many factors, including the timing and extent of spending on research and development and the market acceptance of the Company’s products. The Company will need to obtain additional financing in order to complete clinical studies and launch and commercialize any product candidates for which it receives regulatory approval. There can be no assurance that such financing will be available or will be on terms acceptable to the Company. As of June 30, 2024, the Company had cash and cash equivalents of $172.7 million, which the Company believes will be sufficient to fund its planned operations for a period of at least twelve months from the date of issuance of these unaudited condensed consolidated financial statements. The Company has based this estimate on assumptions that may prove to be wrong, and its operating plan may change as a result of many factors currently unknown to it. As a result, the Company could deplete its capital resources sooner than it currently expects. The Company expects to finance its future cash needs through a combination of equity offerings, debt financings, collaborations, strategic alliances or licensing arrangements. If the Company is unable to obtain funding, the Company would be forced to delay, reduce or eliminate some or all of its research and development programs, preclinical and clinical testing or commercialization efforts, which could adversely affect its business prospects.

Commitments and Contingencies

6 Months Ended

Jun. 30, 2024

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

Note 13—Commitments and Contingencies

Litigation

From time to time, the Company may be subject to various legal proceedings and claims that arise in the ordinary course of its business activities. The Company records a liability when a particular contingency is probable and estimable.

In January 2024 and April 2024, the Company was named a nominal defendant in two putative stockholder derivative actions filed by stockholders of the Company in the Court of Chancery of the State of Delaware. Shortly after filing suit, the plaintiff in the second-filed action voluntarily dismissed his lawsuit and filed a substantially similar action except with fewer named defendants. The complaints assert claims relating to the Company’s August 2023 Private Placement against (i) certain of the Company’s current and former directors and officers for breach of fiduciary duty and unjust enrichment; and (ii) against certain participants in the Company’s August 2023 Private Placement for aiding and abetting breach of fiduciary duty and unjust enrichment. The complaints seek an unspecified award of damages in the Company’s favor, plus pre-judgment and post-judgment interest, and an award to the plaintiffs for the costs and disbursement of the action, including fees for their attorneys, experts, and accountants. In May 2024, the Court consolidated the two actions and set a briefing schedule for motions for appointment of a leadership structure (the “Lead Plaintiff Motions”). The Lead Plaintiff Motions have been fully briefed, and the Court has set a hearing for the Lead Plaintiff Motions for September 5, 2024. The Company has not recorded a liability related to these lawsuits because, at this time, the Company is unable to reasonably estimate possible losses or gains or determine whether an unfavorable outcome is either probable or remote.

Commitments

In the normal course of business, the Company enters into contracts that contain a variety of indemnifications with its directors, officers, employees, licensors, suppliers and service providers. The Company’s maximum exposure under these

arrangements is unknown at June 30, 2024. The Company does not anticipate recognizing any significant losses relating to these arrangements.

Leases - Schedule of Supplemental Cash Flow Information Related to Operating Leases (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Cash Flow, Operating Activities, Lessee [Abstract]
Operating cash flows for operating leases	$ 1,391	$ 1,631

Astellas Agreements - Summary of Allocation for Transaction Price to the Three Performance Obligations (Details) - Astellas - USD ($) $ in Thousands	1 Months Ended	6 Months Ended
	Oct. 31, 2022	Jun. 30, 2024
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Transaction Price Allocation	$ 36,100	$ 36,059
Option to obtain license for Rett
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Transaction Price Allocation		5,485
Option to obtain license for GAN
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Transaction Price Allocation		2,317
Rett research and development activities
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Transaction Price Allocation		$ 28,257

Condensed Consolidated Statements of Stockholders' (Deficit) Equity (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Underwritten Public Offering
Underwriting discounts and commissions and other offering costs	$ 5,024		$ 5,024
Private Placement
Offering costs		$ 40		$ 40

Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2024

Schedule of Share Based Compensation Available for Grant under Incentive Plans

The number of shares available for grant under the Company’s incentive plans were as follows:


	New			Inducement
	Plan			Plan			Total
Available for grant - January 1, 2024		3,162,725			4,000,000			7,162,725
Plan adjustments and amendments		9,348,009			—			9,348,009
Grants		(11,905,262	)		(1,812,700	)		(13,717,962	)
Forfeitures		298,646			311,000			609,646
Available for grant - June 30, 2024		904,118			2,498,300			3,402,418

Schedule of Restricted Stock Units Activity

The Company’s RSU activity for the six months ended June 30, 2024 was as follows:


				Weighted
				Average
				Grant Date
	Number			Fair Value
	of Shares			per Share
Nonvested at January 1, 2024		375,044		$	6.63
Restricted units granted		4,497,141			1.83
Vested		(240,250	)		4.96
Cancelled or forfeited		—			—
Nonvested at June 30, 2024		4,631,935		$	2.06

Schedule of Total Stock-Based Compensation Expense for Stock Options, ESPP, RSAs and RSUs


	For the Three Months Ended June 30,				For the Six Months Ended June 30,
	2024		2023		2024		2023
Research and development expense	$	1,330	$	1,082	$	2,604	$	819
General and administrative expense		2,002		1,140		3,926		3,078
Total	$	3,332	$	2,222	$	6,530	$	3,897

Stock Options

Schedule of Assumptions Used to Estimate Fair Value of Stock Options

The following weighted-average assumptions were used to estimate the fair value of time-based vesting stock options that were granted during the three and six months ended June 30, 2024 and 2023:


	Three Months Ended June 30,						Six Months Ended June 30,
	2024			2023			2024			2023
Risk-free interest rate		4.55	%		3.72	%		4.04	%		3.61	%
Expected dividend yield		—			—			—			—
Expected term (in years)		5.9			5.8			6.1			5.9
Expected volatility		89	%		81	%		89	%		81	%

Schedule of Stock Option Activity

The following table summarizes time-based vesting stock option activity, during the six months ended June 30, 2024:


						Weighted
				Weighted		Average		Aggregate
				Average		Remaining		Intrinsic
	Stock			Exercise		Contractual		Value
	Options			Price		Life (in years)		(in thousands)
Outstanding at January 1, 2024		5,960,922		$	5.75		8.7	$	1,960
Options granted		9,220,821			1.96
Exercised		(2,062	)		1.18
Options cancelled or forfeited		(534,893	)		2.29
Options expired		(68,701	)		17.17
Outstanding at June 30, 2024		14,576,087		$	3.43		9.0	$	6,866
Options exercisable at June 30, 2024		2,667,407		$	9.05		7.9	$	1,024

Performance Stock Options | Initial Options and Original Options

Schedule of Assumptions Used to Estimate Fair Value of Stock Options

The following weighted-average assumptions were used to estimate the fair value of the options granted in February 2023 and the Original Options that were granted in May 2023:




Risk-free interest rate	4.02	%
Expected dividend yield	—
Expected term (in years)	6.0
Expected volatility	81	%

Performance Stock Options | Modified Options

Schedule of Assumptions Used to Estimate Fair Value of Stock Options

The following assumptions were used to estimate the fair value of the Modified Options:



Risk-free interest rate	3.90	%
Expected dividend yield	—
Expected term (in years)	5.8
Expected volatility	88	%

Warrants - Schedule of Warrant Liability (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2024 USD ($)
Warrants and Rights Note Disclosure [Abstract]
Balance at January 1, 2024	$ 454
Change in fair value	142
Balance at March 31, 2024	$ 596

Warrants - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands					1 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 26, 2024	Aug. 16, 2023	Aug. 14, 2023	Apr. 05, 2023	Jul. 31, 2024	Apr. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023	Nov. 15, 2023
Class of Warrant or Right [Line Items]
Common stock, shares issued							201,381,450		201,381,450		186,960,193
Common stock, par value per share							$ 0.00001		$ 0.00001		$ 0.00001
General and administrative							$ 7,338	$ 5,988	$ 14,422	$ 14,739
Warrant liability fair value adjustment									142
Common Stock
Class of Warrant or Right [Line Items]
Share price												$ 1.68
2023 Pre-Funded Warrants
Class of Warrant or Right [Line Items]
Warrant liability fair value adjustment											$ 34,500
Warrant liability reclassified into equity											74,300
Private Placement
Class of Warrant or Right [Line Items]
Gross proceeds from issuance of common stock										$ 500
Securities Purchase Agreement \| 2023 Pre-Funded Warrants
Class of Warrant or Right [Line Items]
Common stock, par value per share			$ 0.001
Securities Purchase Agreement \| August 2023 Private Placement
Class of Warrant or Right [Line Items]
Common stock, shares issued			122,412,376
Securities Purchase Agreement \| August 2023 Private Placement \| 2023 Pre-Funded Warrants
Class of Warrant or Right [Line Items]
Warrants issued			44,250,978
Purchase price per share of common stock			$ 0.9
Exercise price of warrants Per Share			$ 0.001
Securities Purchase Agreement \| Private Placement
Class of Warrant or Right [Line Items]
Beneficial ownership limitation notice period (in days)			61 days
Increase or decrease in beneficial ownership limitation percentage			19.99%
Gross proceeds from issuance of common stock		$ 150,000
Net proceeds from issuance of common stock		$ 140,300
Securities Purchase Agreement \| Private Placement \| SSI Strategy Holdings LLC
Class of Warrant or Right [Line Items]
Common stock, shares issued						705,218
Warrants issued						525,000
Exercise price of warrants Per Share						$ 0.709
Warrants term						10 years
Aggregate gross proceeds						$ 500
Securities Purchase Agreement \| Private Placement \| 2023 Pre-Funded Warrants
Class of Warrant or Right [Line Items]
Purchase price per share of common stock			$ 0.9
Incurred placement agent commissions and other issuance costs									9,700
Allocated to shares, deduction to Additional paid-In capital									7,100
General and administrative											$ 2,600
SSI Warrants
Class of Warrant or Right [Line Items]
Warrant liability fair value adjustment									$ 100
Issuance of fair value warrant				$ 300
Class of warrant or right vested and exercisable shares							316,667		316,667
Warrants Exercised							0		0
Underwriting Agreement
Class of Warrant or Right [Line Items]
Common stock, shares issued	14,361,113
Underwriter agreed to purchase share price of per share	$ 2.115
Underwriting Agreement \| Common Stock
Class of Warrant or Right [Line Items]
Purchase price per share of common stock	2.25
Offering price per share	2.25
Underwriter agreed to purchase share price of per share	$ 2.115
Underwriting Agreement \| Pre-Funded Warrants
Class of Warrant or Right [Line Items]
Warrants issued	18,972,221
Purchase price per share of common stock	$ 2.249
Exercise price of warrants Per Share	0.001
Underwriter agreed to purchase share price of per share	$ 2.114
Underwriting Agreement \| June 2024 Pre-Funded Warrants Option One
Class of Warrant or Right [Line Items]
Shares beneficially owned	4.99%
Combined voting power beneficially owned	4.99%
Underwriting Agreement \| June 2024 Pre-Funded Warrants Option Two
Class of Warrant or Right [Line Items]
Shares beneficially owned	9.99%
Combined voting power beneficially owned	9.99%
Underwriting Agreement \| June 2024 Pre-funded Warrants
Class of Warrant or Right [Line Items]
Common stock, shares issued	14,361,113
Warrants issued	18,972,221
Exercise price of warrants Per Share	$ 0.001
Common stock, par value per share	$ 0.001
Beneficial ownership limitation notice period (in days)	61 days
Increase or decrease in beneficial ownership limitation percentage	19.99%
Offering price per share	$ 2.249
Underwriter agreed to purchase share price of per share	$ 2.114
Additional warrants sold upon exercise of underwriters option					0

Income Taxes

6 Months Ended

Jun. 30, 2024

Income Tax Disclosure [Abstract]

Income Taxes

Note 12—Income Taxes

Deferred tax assets and liabilities are determined based on the difference between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. Valuation allowances are provided if based upon the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets. There is no provision for income taxes because the Company has incurred operating losses and capitalized certain items for income tax purposes since its inception and maintains a full valuation allowance against its net deferred tax assets. The reported amount of income tax expense for the period differs from the amount that would result from applying the federal statutory tax rate to net loss before taxes primarily because of the change in valuation allowance.

As of June 30, 2024, there were no material changes to either the nature or the amounts of the uncertain tax positions previously determined for the year ended December 31, 2023.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//740/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-14

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-21

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 270
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482526/740-270-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 17
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-17

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-2

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482603/740-30-50-2

+ Details

Stock-Based Compensation - Schedule of Total Stock-Based Compensation Expense for Stock Options, ESPP, RSAs and RSUs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 3,332	$ 2,222	$ 6,530	$ 3,897
Research and Development Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	1,330	1,082	2,604	819
General and Administrative Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 2,002	$ 1,140	$ 3,926	$ 3,078

Balance Sheet Components - Schedule of Property, Plant and Equipment Net (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 14,142	$ 13,805
Accumulated depreciation	(3,629)	(2,979)
Property, plant and equipment, net	10,513	10,826
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	2,117	2,117
Laboratory Equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	3,008	2,868
Computer Equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	1,271	1,133
Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	864	864
Construction in Progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 6,882	$ 6,823

Net Loss Per Common Share - Additional Information (Details) - Securities Purchase Agreement - $ / shares	Jun. 30, 2024	Aug. 14, 2023
2023 Pre-Funded Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Exercise price of warrants Per Share		$ 0.001
June 2024 Pre-Funded Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Exercise price of warrants Per Share	$ 0.001

Strategic Reprioritization - Summary of Accrued Severance Activity Recorded (Details) - Employee Severance $ in Thousands	6 Months Ended
	Jun. 30, 2024 USD ($)
Restructuring Cost And Reserve [Line Items]
Accrued severance as of January 1, 2024	$ 390
Severance paid	$ (390)

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References + Details

Fair Value Measurements - Schedule of Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	$ 172,103	$ 142,425
Trinity Term Loans	37,835	40,508
Success Fee Derivative liability	800	800
SSI Warrant liability	596	454
Total liabilities	39,231	41,762
Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents - money market funds	172,103	142,425
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	172,103	142,425
Level 1 \| Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents - money market funds	172,103	142,425
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trinity Term Loans	37,835	40,508
Success Fee Derivative liability	800	800
SSI Warrant liability	596	454
Total liabilities	$ 39,231	$ 41,762

Stock-Based Compensation - Schedule of Share Based Compensation Available for Grant under Incentive Plans (Details)	6 Months Ended
	Jun. 30, 2024 shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Available for grant beginning of period	7,162,725
Plan adjustments and amendments	9,348,009
Grants	(13,717,962)
Forfeitures	609,646
Available for grant end of period	3,402,418
New Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Available for grant beginning of period	3,162,725
Plan adjustments and amendments	9,348,009
Grants	(11,905,262)
Forfeitures	298,646
Available for grant end of period	904,118
Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Available for grant beginning of period	4,000,000
Grants	(1,812,700)
Forfeitures	311,000
Available for grant end of period	2,498,300

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

+ Details

Strategic Reprioritization (Tables)

6 Months Ended

Jun. 30, 2024

Restructuring and Related Activities [Abstract]

Summary of Accrued Severance Activity Recorded

Payment of these costs are complete as of June 30, 2024. The amount of accrued severance recorded as of June 30, 2024 is as follows (amounts in thousands):


	Accrued Severance
Accrued severance as of January 1, 2024	$	390
Severance recorded		—
Severance paid		(390	)
Accrued severance as of June 30, 2024	$	—

Leases - Schedule of Future Minimum Commitments Under Company's Operating and Finance Leases (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Operating Lease
2024	$ 1,423
2025	2,910
2026	2,485
2027	2,577
2028	2,673
Thereafter	17,045
Total lease payments	29,113
Less: imputed interest	(9,596)
Total lease liabilities	19,517
Operating lease liabilities, current	$ 1,383
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Accrued Liabilities And Other Liabilities
Operating lease liabilities, non-current	$ 18,134	$ 18,953
Total lease liabilities	19,517
Finance Lease
2024	227
2025	454
2026	399
Total lease payments	1,080
Less: imputed interest	(129)
Total lease liabilities	951
Finance lease liabilities, current	$ 371
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Accrued Liabilities And Other Liabilities
Finance, lease liabilities, non-current	$ 580
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Liabilities Noncurrent
Total lease liabilities	$ 951
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Liabilities