Atara Biotherapeutics (ATRA) 10-Q 12 Nov 24 2024 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2024	Nov. 06, 2024
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Sep. 30, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31
Entity Registrant Name	ATARA BIOTHERAPEUTICS, INC.
Entity Central Index Key	0001604464
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Securities Act File Number	001-36548
Entity Tax Identification Number	46-0920988
Entity Address, Address Line One	2380 Conejo Spectrum Street
Entity Address, Address Line Two	Suite 200
Entity Address, City or Town	Thousand Oaks
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	91320
City Area Code	805
Local Phone Number	623-4211
Entity Incorporation, State or Country Code	DE
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Trading Symbol	ATRA
Security Exchange Name	NASDAQ
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		5,759,750

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 46,453	$ 25,841
Short-term investments	20,736	25,884
Restricted cash	146	146
Accounts receivable	1,335	34,108
Inventories	13,980	9,706
Other current assets	9,205	6,184
Total current assets	91,855	101,869
Property and equipment, net	1,661	3,856
Operating lease assets	45,833	54,935
Other assets	3,357	4,844
Total assets	142,706	165,504
Current liabilities:
Accounts payable	2,146	3,684
Accrued compensation	7,768	11,519
Accrued research and development expenses	6,077	17,364
Deferred revenue	116,344	77,833
Other current liabilities	23,644	31,826
Total current liabilities	155,979	142,226
Deferred revenue - long-term	470	37,562
Operating lease liabilities - long-term	35,243	45,693
Liability related to the sale of future revenues - long-term	37,584	34,623
Other long-term liabilities	3,969	4,631
Total liabilities	233,245	264,735
Commitments and contingencies (Note 8)
Stockholders' equity (deficit):
Common stock- $0.0001 par value, 500,000 shares authorized as of September 30, 2024 and December 31, 2023; 5,740 and 4,258 shares issued an outstanding as of September 30, 2024 and December 31, 2023, respectively	1	0
Additional paid-in capital	1,951,298	1,870,123
Accumulated other comprehensive (loss) income	22	(204)
Accumulated deficit	(2,041,860)	(1,969,150)
Total stockholders' equity (deficit)	(90,539)	(99,231)
Total liabilities and stockholders' equity (deficit)	$ 142,706	$ 165,504

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) (Unaudited) - $ / shares	Sep. 30, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	5,740,000	4,258,000
Common stock, shares outstanding	5,740,000	4,258,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Income Statement [Abstract]
Commercialization revenue	$ 40,190	$ 2,020	$ 96,187	$ 3,697
License and collaboration revenue	0	118	0	624
Total revenue	40,190	2,138	96,187	4,321
Costs and operating expenses:
Cost of commercialization revenue	7,602	2,615	14,214	5,726
Research and development expenses	43,924	56,888	122,762	175,185
General and administrative expenses	10,421	12,247	30,446	39,454
Total costs and operating expenses	61,947	71,750	167,422	220,365
Loss from operations	(21,757)	(69,612)	(71,235)	(216,044)
Other income (expense), net:
Interest income	459	1,218	1,513	4,715
Interest expense	(1,183)	(1,395)	(3,598)	(4,109)
Other income (expense), net	555	(27)	617	(234)
Total other income (expense), net	(169)	(204)	(1,468)	372
Loss before provision for (benefit from) income taxes	(21,926)	(69,816)	(72,703)	(215,672)
Provision for (benefit from) income taxes	(17)	(19)	7	4
Net income (loss)	(21,909)	(69,797)	(72,710)	(215,676)
Other comprehensive gain (loss):
Unrealized gain (loss) on available-for-sale securities	36	362	226	1,496
Comprehensive income (loss)	$ (21,873)	$ (69,435)	$ (72,484)	$ (214,180)
Basic net loss per common share	$ (2.93)	$ (16.4)	$ (11.34)	$ (51.27)
Diluted net loss per common share	$ (2.93)	$ (16.4)	$ (11.34)	$ (51.27)
Basic weighted-average shares outstanding	7,466	4,256	6,414	4,207
Diluted weighted-average shares outstanding	7,466	4,256	6,414	4,207

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance at Dec. 31, 2022	$ 126,640		$ 1,821,731	$ (2,067)	$ (1,693,024)
Beginning balance (in shares) at Dec. 31, 2022		3,837
Issuance of common stock through ATM facilities, net of commissions and offering costs, value	590		590
Issuance of common stock through ATM facilities, net of commissions and offering costs, shares		6
RSU settlements, net of shares withheld	(93)		(93)
RSU settlements, net of shares withheld, shares		19
Stock-based compensation expense	11,764		11,764
Net (loss) income	(74,771)				(74,771)
Unrealized gain (loss) on available-for-sale securities	830			830
Ending balance at Mar. 31, 2023	64,960		1,833,992	(1,237)	(1,767,795)
Ending balance (in shares) at Mar. 31, 2023		3,862
Beginning balance at Dec. 31, 2022	126,640		1,821,731	(2,067)	(1,693,024)
Beginning balance (in shares) at Dec. 31, 2022		3,837
Net (loss) income	(215,676)
Unrealized gain (loss) on available-for-sale securities	1,496
Ending balance at Sep. 30, 2023	(50,838)		1,858,433	(571)	(1,908,700)
Ending balance (in shares) at Sep. 30, 2023		4,077
Beginning balance at Mar. 31, 2023	64,960		1,833,992	(1,237)	(1,767,795)
Beginning balance (in shares) at Mar. 31, 2023		3,862
RSU settlements, net of shares withheld	(1)		(1)
Exercise of pre-funded warrants, Share		116
RSU settlements, net of shares withheld, shares		43
Issuance of common stock pursuant to employee stock awards, shares		23
Issuance of common stock pursuant to employee stock awards	747		747
Stock-based compensation expense	12,552		12,552
Net (loss) income	(71,108)				(71,108)
Unrealized gain (loss) on available-for-sale securities	304			304
Ending balance at Jun. 30, 2023	7,454		1,847,290	(933)	(1,838,903)
Ending balance (in shares) at Jun. 30, 2023		4,044
RSU settlements, net of shares withheld, shares		33
Stock-based compensation expense	11,143		11,143
Net (loss) income	(69,797)				(69,797)
Unrealized gain (loss) on available-for-sale securities	362			362
Ending balance at Sep. 30, 2023	(50,838)		1,858,433	(571)	(1,908,700)
Ending balance (in shares) at Sep. 30, 2023		4,077
Beginning balance at Dec. 31, 2023	(99,231)		1,870,123	(204)	(1,969,150)
Beginning balance (in shares) at Dec. 31, 2023		4,258
Issuance of pre-funded warrants to purchase common stock through a registered direct offering, net of offering costs of $177	14,823		14,823
Issuance of common stock through ATM facilities, net of commissions and offering costs, value	9,312		9,312
Issuance of common stock through ATM facilities, net of commissions and offering costs, shares		493
RSU settlements, net of shares withheld	(6)		(6)
RSU settlements, net of shares withheld, shares		63
Stock-based compensation expense	8,397		8,397
Net (loss) income	(31,752)				(31,752)
Unrealized gain (loss) on available-for-sale securities	149			149
Ending balance at Mar. 31, 2024	(98,308)		1,902,649	(55)	(2,000,902)
Ending balance (in shares) at Mar. 31, 2024		4,814
Beginning balance at Dec. 31, 2023	(99,231)		1,870,123	(204)	(1,969,150)
Beginning balance (in shares) at Dec. 31, 2023		4,258
Net (loss) income	(72,710)
Unrealized gain (loss) on available-for-sale securities	226
Ending balance at Sep. 30, 2024	(90,539)	$ 1	1,951,298	22	(2,041,860)
Ending balance (in shares) at Sep. 30, 2024		5,740
Beginning balance at Mar. 31, 2024	(98,308)		1,902,649	(55)	(2,000,902)
Beginning balance (in shares) at Mar. 31, 2024		4,814
RSU settlements, net of shares withheld	(1)		(1)
RSU settlements, net of shares withheld, shares		81
Issuance of common stock pursuant to employee stock awards, shares		9
Issuance of common stock pursuant to employee stock awards	113		113
Stock-based compensation expense	6,336		6,336
Net (loss) income	(19,049)				(19,049)
Unrealized gain (loss) on available-for-sale securities	41			41
Ending balance at Jun. 30, 2024	(110,868)		1,909,097	(14)	(2,019,951)
Ending balance (in shares) at Jun. 30, 2024		4,904
Issuance of pre-funded warrants to purchase common stock through a registered direct offering, net of offering costs of $177	35,780	$ 1	35,779
RSU settlements, net of shares withheld, shares		77
Stock-based compensation expense	6,422		6,422
Net (loss) income	(21,909)				(21,909)
Unrealized gain (loss) on available-for-sale securities	36			36
Ending balance at Sep. 30, 2024	$ (90,539)	$ 1	$ 1,951,298	$ 22	$ (2,041,860)
Ending balance (in shares) at Sep. 30, 2024		5,740

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2024	Mar. 31, 2024	Mar. 31, 2023
Issuance of pre-funded warrants net of offering costs	$ 220	$ 177
At The Market Offering | Common Stock
Stock issuance, discounts, commissions and offering costs		$ 168	$ 97

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Operating activities
Net income (loss)	$ (72,710)	$ (215,676)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Stock-based compensation expense	21,155	35,459
Depreciation and amortization expense	3,951	3,624
Accretion of liability related to sale of future revenues	3,180	3,729
Amortization (accretion) of investment premiums (discounts)	(30)	(1,320)
Non-cash operating lease expense	9,102	8,847
Other non-cash items, net	(340)	148
Changes in operating assets and liabilities:
Accounts receivable	32,773	40,058
Inventories	(4,274)	(5,005)
Other current assets	(3,135)	920
Other assets	(254)	(119)
Accounts payable	(1,537)	(319)
Accrued compensation	(3,751)	(3,229)
Accrued research and development expenses	(11,287)	(1,024)
Other current liabilities	(10,446)	607
Deferred revenue	1,419	540
Operating lease liabilities	(8,062)	(9,953)
Other long-term liabilities	0	142
Net cash used in operating activities	(44,246)	(142,571)
Investing activities
Purchases of short-term investments	(19,665)	(83,647)
Proceeds from maturities and sales of short-term investments	25,069	198,723
Purchases of property and equipment	(156)	(1,179)
Proceeds from sale of property and equipment	0	25
Net cash provided by (used in) investing activities	5,248	113,922
Financing activities
Proceeds from sale of common stock and pre-funded warrants in registered direct offerings, net	50,813	0
Proceeds from issuance of common stock through ATM facilities, net	9,348	590
Proceeds from employee stock awards	113	747
Taxes paid related to net share settlement of restricted stock units	0	(94)
Principal payments on finance lease obligations	(657)	(732)
Other financing activities, net	(7)	(13)
Net cash provided by financing activities	59,610	498
Increase (decrease) in cash, cash equivalents and restricted cash	20,612	(28,151)
Cash, cash equivalents and restricted cash at beginning of period	25,987	93,088
Cash, cash equivalents and restricted cash at end of period	46,599	64,937
Non-cash investing and financing activities
Property and equipment purchases included in accounts payable and other accrued liabilities	0	20
Accrued costs related to direct registered offering	210	0
Supplemental cash flow disclosure
Cash paid for interest	497	332
Cash paid for income taxes	$ 24	$ 2

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (21,909)	$ (19,049)	$ (31,752)	$ (69,797)	$ (71,108)	$ (74,771)	$ (72,710)	$ (215,676)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Sep. 30, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Description of Business

Description of Business	9 Months Ended
	Sep. 30, 2024
Description Of Business [Abstract]
Description of Business	1. Description of Business Atara Biotherapeutics, Inc. (Atara, we, our or the Company) was incorporated in August 2012 in Delaware . Atara is a leader in T-cell immunotherapy, leveraging its novel allogeneic Epstein-Barr Virus (EBV) T-cell platform to develop transformative therapies for patients with cancer and autoimmune disease. We have several T-cell immunotherapies in clinical development and are progressing multiple next-generation allogeneic chimeric antigen receptor T-cell (CAR T) programs. Our most advanced T-cell immunotherapy program, tab-cel ® (tabelecleucel), has received marketing authorization approval under the proprietary name Ebvallo™ by the European Commission (EC) for commercial sale and use in the European Economic Area (EEA), by the Medicines and Healthcare products Regulatory Agency (MHRA) for commercial sale and use in the United Kingdom (UK) and by Swissmedic for commercial sale and use in Switzerland. Tab-cel is currently in Phase 3 development in the US. In October 2021, we entered into a commercialization agreement (Pierre Fabre Commercialization Agreement) with Pierre Fabre Medicament (Pierre Fabre), as amended in September 2022, pursuant to which we granted to Pierre Fabre an exclusive, field-limited license to commercialize and distribute Ebvallo in Europe and select emerging markets in the Middle East, Africa, Eastern Europe and Central Asia (the Initial Territory), following regulatory approval. In October 2023, we amended and restated the Pierre Fabre Commercialization Agreement (A&R Commercialization Agreement). Pursuant to the A&R Commercialization Agreement, Pierre Fabre’s exclusive rights to research, develop, manufacture, commercialize and distribute tab-cel (Ebvallo) were expanded to include all other countries in the world (Additional Territory) in addition to the Initial Territory (Initial Territory and Additional Territory together, the Territory), subject to our performance of certain obligations. See Note 5 for further information. In December 2022, we sold a portion of our right to receive royalties and certain milestones in Ebvallo under the Pierre Fabre Commercialization Agreement to HCR Molag Fund L.P. (HCRx) for a total investment amount of $ 31.0 million, subject to a repayment cap between 185 % and 250 % of the total investment amount by HCRx. See Note 6 for further information. We have licensed rights to T-cell product candidates from Memorial Sloan Kettering Cancer Center (MSK), rights related to our next-generation CAR T programs from MSK, and rights to know-how and technology from the Council of the Queensland Institute of Medical Research (QIMR Berghofer). See Note 8 for further information. We and FUJIFILM Diosynth Biotechnologies California, Inc. (FDB) entered into a Master Services and Supply Agreement and related Statements of Work (collectively, the Fujifilm MSA), which became effective in April 2022 and could extend for up to ten years. Pursuant to the Fujifilm MSA, FDB will supply us with specified quantities of our cell therapy product candidates and any products approved by regulatory authorities, manufactured in accordance with cGMP standards. See Note 8 for further information.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The accompanying unaudited interim condensed consolidated financial statements include the accounts of Atara and its wholly owned subsidiaries and have been prepared in accordance with U.S. generally accepted accounting principles (U.S. GAAP) and the requirements of the Securities and Exchange Commission (SEC) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP can be condensed or omitted. These unaudited interim condensed consolidated financial statements should therefore be read in conjunction with the audited consolidated financial statements and notes for the year ended December 31, 2023, included in the Company’s Annual Report on Form 10-K filed with the SEC on March 28, 2024. In the opinion of management, the condensed consolidated financial statements reflect all adjustments, consisting only of normal recurring adjustments, which are necessary for a fair presentation of the Company’s condensed consolidated financial statements. The results of operations for any interim period are not necessarily indicative of the results to be expected for the full year or any other future period. The condensed consolidated balance sheet as of December 31, 2023 has been derived from audited consolidated financial statements at that date but does not include all of the information required by U.S. GAAP for complete consolidated financial statements. June 2024 Reverse Stock Split At our annual meeting of stockholders held on June 10, 2024, the stockholders of Atara approved a proposal to authorize our Board of Directors (the Board) to amend our Amended and Restated Certificate of Incorporation to effect a reverse stock split. The Board approved the reverse stock split on June 10, 2024 and, on June 20, 2024, we effected a 1-for-25 reverse stock split of our common stock. The par value and the authorized shares of the common stock were not adjusted as a result of the reverse stock split. All equity related information including per share amounts for all periods presented in these condensed consolidated financial statements and the notes thereto have been adjusted retroactively, where applicable, to reflect the effect of this reverse stock split. Liquidity Risk We have incurred significant operating losses since inception and have relied primarily on public and private equity financings and receipts from commercialization and license and collaboration agreements to fund our operations. As we continue to incur losses, our transition to profitability will depend on the successful development, approval and commercialization of product candidates and on the achievement of sufficient revenues to support our cost structure. We may never achieve sustained operating cash inflows or profitability. Going Concern We have incurred operating losses since inception and we expect that existing cash, cash equivalents and short-term investments as of September 30, 2024, will not be sufficient to fund our planned operations for at least 12 months from the date of issuance of these condensed consolidated financial statements. Although we anticipate the receipt of certain payments from the amended and restated Pierre Fabre Commercialization Agreement in 2025, such payments are contingent upon the approval of the tab-cel BLA, which is dependent upon the completion of specific development and regulatory activities by us and actions taken by third parties, and are, therefore, uncertain at this time. To alleviate the conditions that raise substantial doubt about our ability to continue as a going concern, we plan to secure additional capital, potentially through a combination of public or private security offerings; use of our ATM facility as described in Note 9; and/or strategic transactions. We may need to raise additional funding as required based on the status of our development programs and our projected cash flows. Although we have been successful in raising capital in the past, and expect to continue to raise capital as required, there is no assurance that we will be successful in obtaining sufficient funding on terms acceptable to us to fund continuing operations, if at all, or identify and enter into any strategic transactions that will provide the capital that we will require. If we are unable to obtain sufficient funding on acceptable terms, we could be forced to delay, limit, reduce or terminate preclinical studies, clinical studies or other development activities for one or more of our product candidates, which could have a material adverse effect on our business, results of operations, and financial condition. Accordingly, we have concluded that substantial doubt exists with respect to our ability to continue as a going concern for at least 12 months after the issuance of the accompanying condensed consolidated financial statements. The condensed consolidated financial statements do not include any adjustments that might result from the outcome of this uncertainty. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates, assumptions and judgments that affect the amounts reported in the financial statements and accompanying notes. Significant estimates relied upon in preparing these financial statements include estimates related to revenue recognition, accrued research and development expenses, stock-based compensation expense, income taxes and the liability related to the sale of future revenues. Actual results could differ materially from those estimates. Recent Accounting Pronouncements We consider the applicability and impact of any recent Accounting Standards Update (ASU) issued by the Financial Accounting Standards Board (FASB). Other than the ASUs listed below, all other ASUs were assessed and determined to be either not applicable to Atara or are expected to have minimal impact on our condensed consolidated financial statements. In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. The amendment requires disclosure of significant segment expenses that are regularly provided to the chief operating decision maker and included within each reported measure of segment profit or loss, an amount and description of its composition for other segment items, and interim disclosures of a reportable segment’s profit or loss and assets. Additionally, all disclosure requirements under the guidance are required for public entities with a single reportable segment and are to be applied retrospectively to all periods presented. We will adopt the amendments effective for the fiscal year ending December 31, 2024, and for interim periods within fiscal years beginning January 1, 2025. The adoption of ASU 2023-07 will not have a material impact on our consolidated financial statements and will consist of the inclusion of additional disclosures related to our single reportable segment in the notes to the consolidated financial statements. The amendments in this update do not affect the recognition, measurement or financial statement presentation of expenses. In December 2023, the FASB issued ASU No. 2023-09 Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which requires enhancements to certain income tax disclosures, most notably the income tax rate reconciliation and income taxes paid. We will adopt the amendments effective for the fiscal year ending December 31, 2025. We do not expect the adoption of this standard will have a material impact on our disclosures.

Net Loss per Common Share

Net Loss per Common Share	9 Months Ended
	Sep. 30, 2024
Earnings Per Share [Abstract]
Net Loss per Common Share	3. Net Loss per Common Share Basic net loss per common share is calculated by dividing net loss by the weighted-average number of shares of common stock and pre-funded warrants outstanding during the period, without consideration of common share equivalents. Diluted net loss per common share is computed by dividing net loss by the weighted-average number of shares of common stock, pre-funded warrants and common share equivalents outstanding for the period. The pre-funded warrants are included in the computation of basic and diluted net loss per common share as the exercise price is negligible and the pre-funded warrants are fully vested and exercisable. Common share equivalents are only included in the calculation of diluted net loss per common share when their effect is dilutive. Potential dilutive securities, which include unvested restricted stock units (RSUs), unvested performance-based RSUs and performance-based options to purchase common stock for which established performance criteria have been achieved as of the end of the respective periods, vested and unvested options to purchase common stock and shares to be issued under our employee stock purchase plan (ESPP), have been excluded from the computation of diluted net loss per common share as the effect is antidilutive. Therefore, the denominator used to calculate both basic and diluted net loss per common share is the same in all periods presented. The following table represents the potential common shares issuable pursuant to outstanding securities as of the related period end dates that were excluded from the computation of diluted net loss per common share, as their inclusion would have an antidilutive effect: As of September 30, 2024 2023 Unvested RSUs 495,996 338,244 Vested and unvested options 263,788 491,521 ESPP share purchase rights 34,511 18,942 Total 794,295 848,707

Financial Instruments

Financial Instruments	9 Months Ended
	Sep. 30, 2024
Financial Instruments Disclosure [Abstract]
Financial Instruments	4. Financial Instruments Our financial assets are measured at fair value on a recurring basis using the following hierarchy to prioritize valuation inputs, in accordance with applicable U.S. GAAP: Level 1: Quoted prices in active markets for identical assets or liabilities that we have the ability to access. Level 2: Observable market-based inputs or unobservable inputs that are corroborated by market data such as quoted prices, interest rates and yield curves. Level 3: Inputs that are unobservable data points that are not corroborated by market data. We review the fair value hierarchy classification on a quarterly basis. Changes in the ability to observe valuation inputs may result in a reclassification of levels of certain securities within the fair value hierarchy. We recognize transfers into and out of levels within the fair value hierarchy in the period in which the actual event or change in circumstances that caused the transfer occurs. There have been no transfers between Level 1, Level 2 and Level 3 in any periods presented. Financial assets and liabilities are considered Level 2 when their fair values are determined using inputs that are observable in the market or can be derived principally from or corroborated by observable market data such as pricing for similar securities, recently executed transactions, cash flow models with yield curves, and benchmark securities. In addition, Level 2 financial instruments are valued using comparisons to like-kind financial instruments and models that use readily observable market data as their basis. U.S. Treasury, government agency and corporate debt obligations, commercial paper and asset-backed securities are valued primarily using market prices of comparable securities, bid/ask quotes, interest rate yields and prepayment spreads and are included in Level 2. Financial assets and liabilities are considered Level 3 when their fair values are determined using pricing models, discounted cash flow methodologies, or similar techniques, and at least one significant model assumption or input is unobservable. We have no Level 3 financial assets or liabilities. The following tables summarize the estimated fair value and related valuation input hierarchy of our available-for-sale securities as of each period end: Total Total Total Total Amortized Unrealized Unrealized Estimated As of September 30, 2024: Input Level Cost Gain Loss Fair Value (in thousands) Money market funds Level 1 $ 23,334 $ — $ — $ 23,334 U.S. Treasury obligations Level 2 40,472 24 — $ 40,496 Corporate debt obligations Level 2 1,497 — ( 2 ) $ 1,495 Commercial paper Level 2 495 — — $ 495 Total available-for-sale securities 65,798 24 ( 2 ) 65,820 Less: amounts classified as cash equivalents ( 45,077 ) ( 7 ) — ( 45,084 ) Amounts classified as short-term investments $ 20,721 $ 17 $ ( 2 ) $ 20,736 Total Total Total Total Amortized Unrealized Unrealized Estimated As of December 31, 2023: Input Level Cost Gain Loss Fair Value (in thousands) Money market funds Level 1 $ 14,376 $ — $ — $ 14,376 U.S. Treasury obligations Level 2 9,928 1 — 9,929 Corporate debt obligations Level 2 26,089 — ( 205 ) 25,884 Total available-for-sale securities 50,393 1 ( 205 ) 50,189 Less: amounts classified as cash equivalents ( 24,304 ) ( 1 ) — ( 24,305 ) Amounts classified as short-term investments $ 26,089 $ — $ ( 205 ) $ 25,884 The amortized cost and fair value of our available-for-sale securities by contractual maturity were as follows: As of September 30, 2024 As of December 31, 2023 Amortized Estimated Amortized Estimated Cost Fair Value Cost Fair Value (in thousands) (in thousands) Maturing within one year $ 65,798 $ 65,820 $ 50,393 $ 50,189 Maturing in one to five years — — — — Total available-for-sale securities $ 65,798 $ 65,820 $ 50,393 $ 50,189 We considered the current and expected future global economic and market conditions, including, but not limited to, the wars in Ukraine and the Middle East and increased tensions between the U.S. and China, and determined that our investments have not been significantly impacted. As of September 30, 2024, no significant facts or circumstances were present to indicate a deterioration in the creditworthiness of the issuers of the available-for-sale securities we hold, and we have no requirement or intention to sell these securities before maturity or recovery of their amortized cost basis. For all securities with a fair value less than its amortized cost basis, we determined the decline in fair value below amortized cost basis to be non-credit related and no allowance for losses has been recorded. During the three and nine months ended September 30, 2024 and 2023, we did not recognize any impairment losses on our investments. We have elected the practical expedient to exclude the applicable accrued interest from both the fair value and the amortized cost basis of our available-for-sale securities for purposes of identifying and measuring an impairment. We present accrued interest receivable related to our available-for-sale securities in other current assets, separate from short-term investments, on our condensed consolidated balance sheet. As of September 30, 2024 and December 31, 2023 , accrued interest receivable was $ 0.1 million and $ 0.3 million, respectively. We have no t written off any accrued interest receivables during the three and nine months ended September 30, 2024 and 2023. In addition, restricted cash collateralized by money market funds is a financial asset measured at fair value and is a Level 1 financial instrument under the fair value hierarchy. The following table provides a reconciliation of cash, cash equivalents and restricted cash within the condensed consolidated balance sheets that sum to the total of the same such amounts in the condensed consolidated statement of cash flows: September 30, December 31, 2024 2023 (in thousands) Cash and cash equivalents $ 46,453 $ 25,841 Restricted cash – short term 146 146 Total cash, cash equivalents and restricted cash $ 46,599 $ 25,987

Out-license Agreements

Out-license Agreements	9 Months Ended
	Sep. 30, 2024
License Collaboration And Manufacturing Agreements [Abstract]
Out-license Agreements	5. Out-license Agreements Pierre Fabre Agreements In October 2021, we entered into the Pierre Fabre Commercialization Agreement, pursuant to which, we granted to Pierre Fabre an exclusive, field-limited license to commercialize and distribute Ebvallo in Europe and select emerging markets in the Initial Territory following regulatory approval. In September 2022, we entered into Amendment No. 1 to the Pierre Fabre Commercialization Agreement (the PF Amendment). Under the terms of the PF Amendment, following EC approval of Ebvallo for EBV+ PTLD and subsequent filing of the Marketing Authorization Application (MAA) transfer to Pierre Fabre, we received an additional $ 30 million milestone payment in exchange for, among other things, a reduction in: (i) royalties we are eligible to receive as a percentage of net sales of tab-cel (Ebvallo) in the Initial Territory, and (ii) the supply price mark up on tab-cel purchased by Pierre Fabre. Additionally, we agreed to extend the time period for provision of certain services to Pierre Fabre in the Initial Territory at our cost pursuant to the Pierre Fabre Commercialization Agreement. In December 2022, we sold a portion of our right to receive royalties and certain milestone payments related to Ebvallo in the Initial Territory under the Pierre Fabre Commercialization Agreement to HCRx for a total investment amount of $ 31.0 million, subject to a repayment cap between 185 % and 250 % of the total investment amount by HCRx. See Note 6 for further information related to the agreement with HCRx. In October 2023, we entered into the A&R Commercialization Agreement with Pierre Fabre. Pursuant to the A&R Commercialization Agreement, Pierre Fabre’s exclusive rights to research, develop, manufacture, commercialize and distribute tab-cel were expanded to include the Additional Territory in addition to the Initial Territory, subject to our performance of certain obligations as described below. Pierre Fabre paid us an upfront cash payment of $ 45.0 million for the exclusive license grant for the Initial Territory in the fourth quarter of 2021. In December 2022, we met the contractual right to receive $ 40.0 million in milestone payments upon certain regulatory milestones, for which the cash was received in January 2023. Subject to the terms of the royalty purchase agreement with HCRx, as described in Note 6, we are entitled to receive an aggregate of up to $ 308.0 million in remaining milestone payments upon achieving certain regulatory and commercial milestones in addition to double-digit tiered royalties as a percentage of net sales of Ebvallo in the Initial Territory, until the later of 12 years after the first commercial sale in each such country, the expiration of specified patent rights, or the expiration of all regulatory exclusivity for Ebvallo on a country-by-country basis. In December 2023, upon the effective date of the A&R Commercialization Agreement, we met the contractual right to receive an additional upfront cash payment of $ 20.0 million for the expanded exclusive license grant in the Additional Territory, for which the cash was received in January 2024. In March 2024, we met the contractual right to receive $ 20.0 million in milestone payments upon achieving a regulatory milestone, for which the cash was received in April 2024. In July 2024, we met the contractual right to receive an additional $ 20.0 million in milestone payments upon achieving acceptance of our biologics license application (BLA) for tab-cel by the United States Food and Drug Administration (FDA) and we received the cash in August 2024. We will also be entitled to receive an aggregate of up to $ 580.0 million in additional payments upon achieving certain regulatory and commercial milestones relating to tab-cel in the Additional Territory. We will be eligible to receive double-digit tiered royalties as a percentage of net sales of tab-cel in the Additional Territory until the later of 12 years after the first commercial sale in each such country, the expiration of specified patent rights in each such country, or the expiration of all regulatory exclusivity for tab-cel on a country-by-country basis. We have entered into a separate manufacturing and supply agreement with Pierre Fabre for us to manufacture Ebvallo for Pierre Fabre to use in the Initial Territory based on a fixed price through December 31, 2023 and at a price equal to cost plus a margin for orders placed after December 31, 2023, subject to a maximum annual increase. Pierre Fabre will assume the responsibility and cost for the manufacture and supply of tab-cel (Ebvallo) in the Territory upon the Manufacturing Transition Date, which is defined as the earlier of: i) all activities relating to the transfer of tab-cel manufacturing, pursuant to the A&R Commercialization Agreement, from Atara to Pierre Fabre have been completed to the reasonable satisfaction of both parties, or ii) December 31, 2025, through the remainder of the term of the A&R Commercialization Agreement. Pierre Fabre and we are to use commercially reasonable efforts to achieve this prior to the earlier transfer date from Atara to Pierre Fabre of the first marketing authorization in the Additional Territory or the first BLA (PF Transfer Date). Prior to the Manufacturing Transition Date, we are responsible for manufacturing and supplying tab-cel (Ebvallo) to Pierre Fabre in the Territory. Without transfer of the manufacturing technology, no other party can manufacture tab-cel (Ebvallo). In August 2024, we sold certain intermediates used in the manufacture of Ebvallo to Pierre Fabre for $ 15.5 million, transferring title and risk of loss to these intermediates in advance of the Manufacturing Transition Date, which guarantees Pierre Fabre supply and control of intermediates to be used in the production of Ebvallo. We received payment for these intermediates in September 2024. Cell selection is the process of identifying the appropriate cell line from available tab-cel inventory to be used for a patient. We are responsible for the performance of cell selection services in the Initial Territory at our cost through the earlier of the PF Transfer Date, June 30, 2025 or a date otherwise agreed to by Pierre Fabre and us. To the extent that the transfer of cell selection technology occurs subsequent to June 30, 2025, we will be responsible for the performance of cell selection services in the Initial Territory at Pierre Fabre’s cost until cell selection technology is transferred to Pierre Fabre. Without transfer of the cell selection technology, no other party can provide such services. We are responsible for the performance of cell selection services in the Additional Territory through the earlier of the PF Transfer Date or a date otherwise agreed to by Pierre Fabre and us, at the sole expense of Pierre Fabre. As part of the Pierre Fabre Commercialization Agreement, we formed a joint steering committee (JSC) with Pierre Fabre that provides oversight, decision making and implementation guidance regarding the commercialization activities, the responsibilities of which has been expanded to cover the incremental scope of the A&R Commercialization Agreement. During the applicable period specified in the A&R Commercialization Agreement, we are responsible for various development, safety, process science, and regulatory activities, including obtaining regulatory approval in the United States for tab-cel for EBV-associated post-transplant lymphoproliferative disease. Pierre Fabre will pay us for these services in accordance with the A&R Commercialization Agreement. Pierre Fabre will be responsible, at its cost, for obtaining and maintaining all other required regulatory approvals and for commercialization and distribution of tab-cel in the Additional Territory, including conducting any other clinical study required. We will own any intellectual property rights developed solely by us under the A&R Commercialization Agreement. Accounting Analysis Identification of the Contract We assessed this arrangement in accordance with ASC 606 and concluded that the promises in the A&R Commercialization Agreement represent transactions with a customer. Identification of the Promises and Performance Obligations We identified four performance obligations under the A&R Commercialization Agreement, consisting of the following material promises: (1) the transfer of intellectual property rights in the form of a license in the Initial Territory, the obligation to participate in the JSC, the manufacture and supply of Ebvallo, a material right for purchases associated with the manufacture and supply of Ebvallo, and the performance of cell-selection services. We concluded that the individual promises are not distinct because Pierre Fabre cannot benefit from the license without the other services and vice versa, since Pierre Fabre is not capable of carrying out the manufacturing and supply and cell selection services on their own, until the transfer of the related technologies occur. Consequently, these promises represent a single performance obligation, collectively referred to as the Initial Territory Obligation. (2) the transfer of intellectual property rights in the form of a license in the Additional Territory, the manufacture and supply of tab-cel and the performance of cell-selection services, as well as the promises to transfer the related technologies, and perform certain development, safety, regulatory and information technology transition services. We concluded that the promises are not distinct because Pierre Fabre cannot benefit from the license without the other services and vice versa. Consequently, these promises represent a single performance obligation, collectively referred to as the Additional Territory Obligation. (3) performance of certain process science services, referred to as the Process Sciences Obligation. (4) the sale of certain intermediate inventory used in the production of tab-cel in existence on the Manufacturing Transition Date, referred to as the Intermediate Inventory Obligation. Determination of the Transaction Price Under the Pierre Fabre Commercialization Agreement, we determined that the $ 45.0 million upfront payment constituted the entire consideration to be included in the transaction price at the outset of the arrangement, and the $ 40.0 million in regulatory milestones achieved in December 2022 were added to the transaction price upon meeting the related milestone criteria. The remaining potential regulatory and commercial milestone payments that we are eligible to receive were excluded from the transaction price, as the milestone amounts were fully constrained based on the probability of achievement or have not been earned. None of the future royalty and sales-based milestone payments were included in the transaction price, as the potential payments represent sales-based consideration. We reevaluate the transaction price at the end of each reporting period and as uncertain events are resolved or other changes in circumstances occur, and, as necessary, we adjust our estimate of the transaction price. Upon the effective date of the A&R Commercialization Agreement, the $ 20.0 million additional upfront payment received and estimated revenue for the development, safety, regulatory and process science services were added to the transaction price, and the $ 20.0 million regulatory milestone achieved in March 2024 and the $ 20.0 million regulatory milestone achieved in July 2024 were added to the transaction price upon meeting the related milestone criteria. The remaining potential regulatory and commercial milestone payments that we are eligible to receive were excluded from the transaction price, as the milestone amounts were fully constrained based on the probability of achievement or have not been earned. None of the future royalty and sales-based milestone payments were included in the transaction price, as the potential payments represent sales-based consideration. Allocation of the Transaction Price to Performance Obligations The transaction price was allocated to each performance obligation based on their relative standalone selling price. We developed the estimated standalone selling price for each of the A&R Commercialization Agreement performance obligations with the objective of determining the price at which we would sell such an item if it were to be sold regularly on a standalone basis. Recognition of Revenue Commercialization revenue associated with the Initial Territory Obligation is recognized over the period during which the material right exists, which would end upon the Manufacturing Transition Date. Based on these considerations and our forecast of the timing and associated costs of the purchases related to the manufacture and supply of Ebvallo and estimated timing of technology transfer, we estimate the material right in the Initial Territory will exist for approximately one year. We reassess this evaluation each reporting period. Commercialization revenue associated with sales of Ebvallo and intermediate inventory to Pierre Fabre is deferred until we have performed the associated manufacturing of finished Ebvallo product inventory and cell selection services, or once manufacturing and cell selection technology transfers to Pierre Fabre have been completed. At that point, Pierre Fabre would be able to utilize the inventory it had purchased from us on its own. Commercialization revenue associated with the Additional Territory Obligation and the Process Sciences Obligation is recognized using a cost-based input method based on the amount of actual costs incurred relative to the total budgeted costs expected to be incurred for the respective performance obligations. A cost-based input method of revenue recognition requires us to make estimates of costs to complete our performance obligation. In making such estimates, significant judgment is required to evaluate assumptions related to cost estimates. The cumulative effect of revisions to estimated costs to complete our performance obligation will be recorded in the period in which changes are identified and amounts can be reasonably estimated. We expect to recognize the remaining deferred revenue associated with the Additional Territory Obligation and the Process Sciences Obligation over a period of approximately one year and two years, respectively. We reassess this evaluation each reporting period. The transfer of control occurs over the respective time period and, in our judgment, is the best measure of progress towards satisfying the performance obligation. A significant change in these assumptions and estimates could have a material impact on the timing and amount of revenue recognized in future periods. We expect to recognize revenue associated with the Intermediate Inventory Obligation at a point in time on the Manufacturing Transition Date, which is when title and risk of loss, and thus, control, of the intermediate inventory transfers to Pierre Fabre. Deferred revenue activity related to commercialization revenue for the nine months ended September 30, 2024 was as follows: (in thousands) Deferred revenue, January 1, 2024 $ 115,395 Additions 94,520 Recognized into commercialization revenue ( 93,101 ) Deferred revenue September 30, 2024 116,814 Less: deferred revenue – current portion ( 116,344 ) Deferred revenue – long-term, September 30, 2024 $ 470 During the nine months ended September 30, 2024 , we recognized 31.4 million of revenue that was included in the deferred revenue balance as of December 31, 2023. During the three and nine months ended September 30, 2024, we recognized revenue of $ 8.8 million related to performance obligations partially satisfied in prior periods related to changes in the transaction price upon achievement of development milestones. Costs incurred relating to performing the services within the Additional Territory Obligation and Process Sciences Obligation consist of third party expenses and for time incurred by our employees to satisfy requirements set forth by the A&R Commercialization Agreement. These costs are included in research and development expenses in the condensed consolidated statements of operations and comprehensive income (loss) during the three and nine months ended September 30, 2024. Such costs were $ 11.1 million and $ 33.8 million for the three and nine months ended September 30, 2024, respectively.

Liability Related to the Sale o

Liability Related to the Sale of Future Revenues	9 Months Ended
	Sep. 30, 2024
Liability for Future Policy Benefit, after Reinsurance [Abstract]
Liability Related to the Sale of Future Revenues	6. Liability Related to the Sale of Future Revenues In December 2022, we entered into a Purchase and Sale Agreement (the HCRx Agreement) with HCR Molag Fund, L.P., a Delaware limited partnership, (HCRx). In exchange for a payment of $ 31.0 million (the Investment Amount) to Atara, net of certain transaction expenses, HCRx obtained the right to receive certain Ebvallo royalties and milestone payments payable by Pierre Fabre under the Pierre Fabre Commercialization Agreement up to an agreed upon multiple of the Investment Amount. Under the HCRx Agreement, HCRx is entitled to receive tiered royalties on net sales of Ebvallo in the Initial Territory in amounts ranging from the mid-single digits to double digits based on annual net sales. HCRx is also entitled to certain milestone payments due to Atara from Pierre Fabre. The total royalties and milestones payable to HCRx are capped between 185 % and 250 % of the Investment Amount, depending upon the timing of such royalties and milestones. Upon meeting the cap amount, HCRx’s right to receive royalties and milestone payments will terminate and all rights will revert to Atara. To the extent a certain milestone within the Pierre Fabre Commercialization Agreement is not achieved on or prior to June 30, 2026, we will be required to make a one-time cash payment in the amount of $ 9.0 million to HCRx, and HCRx shall transfer all of its right, title and interest in this certain $ 9.0 million milestone payment to Atara. This payment, if required, would be included in the calculation of aggregate payments made to HCRx. The gross proceeds of the Investment Amount of $ 31.0 million were recorded as a liability related to the sale of future revenues, net of transaction costs of $ 0.4 million, and will be amortized using the effective interest method over the life of the arrangement. To determine the amortization of the recorded liability, we are required to estimate the total amount of future payments to be received by HCRx. The sum of these amounts less the $ 31.0 million proceeds we received will be recorded as interest expense over the life of the HCRx Agreement. We estimate the effective interest rate used to record non-cash interest expense under the HCRx Agreement based on the estimate of future payments to be received by HCRx. On September 30, 2024 , the annual effective interest rate was approximately 11 %. Over the life of the arrangement, the actual effective interest rate will be affected by the amount and timing of the actual and forecasted royalty and milestone payments to HCRx. At each reporting date, we will reassess our estimate of the timing and amounts of future payments made to HCRx, and prospectively adjust the effective interest rate and amortization of the liability as necessary. The following table presents the changes in the liability related to the sale of future revenues under the HCRx Agreement for the nine months ended September 30, 2024: (in thousands) Liability related to sale of future revenues as of January 1, 2024 $ 35,076 Accretion of interest expense on liability related to sale of future revenues 3,180 Amortization of debt discount and debt issuance costs 52 Repayment of the liability ( 132 ) Liability related to the sale of future revenues as of September 30, 2024 38,176 Less: current portion classified within other accrued liabilities ( 592 ) Liability related to sale of future revenues - long-term $ 37,584

Restructuring

Restructuring	9 Months Ended
	Sep. 30, 2024
Restructuring and Related Activities [Abstract]
Restructuring	7. Restructuring In November 2023, we announced a strategic reduction in workforce of approximately 30 %. The workforce reduction included total restructuring charges of $ 6.7 million, comprised primarily of severance payments and wages for the 60-day notice period in accordance with the California Worker Adjustment and Retraining Notification (WARN) Act. In most cases, the severance payments were paid as a lump sum in January 2024. As of September 2024, there are no remaining payments for the November 2023 reduction in workforce. All of the costs were cash expenditures and represent one-time termination benefits. In January 2024, we announced a strategic reduction in workforce of approximately 25 %. The workforce reduction resulted in total restructuring charges of $ 5.1 million, comprised primarily of severance payments and wages for the 60-day notice period in accordance with the California WARN Act. In most cases, the severance payments were paid during the first half of 2024. Certain of the notified employees had employment agreements that provided for separation benefits in the form of salary continuation, which are being paid from February 2024 through January 2025. As of September 30, 2024, approximately $ 0.2 million of further separation payments and benefits are required for the January 2024 reduction in workforce. The majority of the associated costs are cash expenditures and primarily represent one-time termination benefits. The following is a summary of restructuring charges associated with the reductions in force for the periods presented: Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 (in thousands) (in thousands) Research and development expense $ — $ — $ 3,750 $ — General and administrative expense — — 1,357 45 Total restructuring charges $ — $ — $ 5,107 $ 45 The following restructuring liability activity was recorded in connection with the reductions in force for the nine months ended September 30, 2024: (in thousands) Liability balance, January 1, 2024 $ 4,923 Restructuring charges 5,107 Cash payments ( 9,157 ) Non-cash settlements/adjustments ( 666 ) Liability balance, September 30, 2024 $ 207 The liability balance as of September 30, 2024 and December 31, 2023 is recorded within other current liabilities on the accompanying condensed consolidated balance sheet.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	8. Commitments and Contingencies MSK In-license Agreements In June 2015, we entered into an exclusive license agreement with MSK for three clinical stage T-cell therapies. We are required to make payments to MSK based on achievement of specified regulatory and sales-related milestones, as well as mid-single-digit percentage tiered royalty payments based on future sales of products resulting from the development of the licensed product candidates, if any. In addition, under certain circumstances, we are required to make certain minimum annual royalty payments to MSK, which are creditable against earned royalties owed for the same annual period. We are also required to pay a low double-digit percentage of any consideration we receive for sublicensing the licensed rights. The license agreement expires on a product-by-product and country-by-country basis on the latest of: (i) expiration of the last licensed patent rights related to each licensed product, (ii) expiration of any market exclusivity period granted by law with respect to each licensed product, and (iii) a specified number of years after the first commercial sale of the licensed product in each country. Upon expiration of the license agreement, we will retain non-exclusive rights to the licensed products. In May and December 2018, we licensed additional technology from MSK. We are obligated to make additional milestone payments based on achievement of specified development, regulatory and sales-related milestones, as well as mid-single-digit percentage tiered royalty payments based on future sales of products resulting from the development of the licensed product candidates, if any. In March 2021, we amended and restated our license agreement with MSK to terminate our license to certain rights and license additional know-how rights not otherwise covered by our existing agreements. In March 2024, we terminated our license agreements with MSK to the ATA2271 and ATA3271 programs targeting mesothelin. QIMR Berghofer In-license Agreements In October 2015, we entered into an exclusive license agreement and a research and development collaboration agreement with QIMR Berghofer. Under the terms of the license agreement, we obtained an exclusive, worldwide license to develop and commercialize allogeneic T-cell therapy programs utilizing technology and know-how developed by QIMR Berghofer. In September 2016, the exclusive license agreement and research and development collaboration agreement were amended and restated. Under the amended and restated agreements, we obtained an exclusive, worldwide license to develop and commercialize additional T-cell programs, as well as the option to license additional technology that we exercised in June 2018. We further amended and restated our license agreement and research and development collaboration agreements with QIMR Berghofer in August 2019, August 2020 and December 2021, in each case, to terminate our license to certain rights. Our current license agreement also provides for various milestone and royalty payments to QIMR Berghofer based on future product sales, if any. Under the terms of our current research and development collaboration agreement, we are also required to reimburse the cost of agreed-upon development activities related to programs developed under the collaboration. These payments are expensed on a straight-line basis over the related development periods. The agreement also provides for various milestone payments to QIMR Berghofer based on achievement of certain developmental and regulatory milestones. Other In-license and Collaboration Agreements From time to time, we have entered into other license and collaboration agreements with other parties. For example, we licensed rights related to our MSK-partnered next-generation CAR T programs from the National Institutes of Health in December 2018. Milestones and royalties under each of the above agreements are contingent upon future events and will be recorded as expense when the underlying milestones are achieved or royalties are earned. Sales related milestone and royalty costs related to Ebvallo are recorded in cost of commercialization revenue, whereas regulatory milestone costs are recorded in research and development expense. As of September 30, 2024 and December 31, 2023 , there were no material outstanding obligations for milestones and royalties under our license and collaboration agreements. CRL Manufacturing Agreement In December 2019, we entered into a Commercial Manufacturing Services Agreement (the CRL MSA) with Cognate BioServices, Inc., which was acquired by Charles River Laboratories Inc. (CRL) in March 2021. Pursuant to the CRL MSA, CRL provides manufacturing services for our product and certain of our product candidates. The CRL MSA expired on August 31, 2024. We are currently in negotiations with CRL for an amendment to further extend the term of the CRL MSA and for a new commercial drug product supply agreement. However, there can be no assurance that we will be able to further extend the CRL MSA or enter into a new commercial drug product supply agreement with CRL on terms favorable or acceptable to us, or at all. If we are unable to enter into a new commercial drug product supply agreement or extend the CRL MSA, we may need to identify alternative sources of drug product supply. Fujifilm Master Services and Supply Agreement In January 2022, we entered into the Fujifilm MSA, which became effective upon the closing of the sale of the ATOM Facility on April 4, 2022 and could extend for up to ten years . Pursuant to the Fujifilm MSA, FDB will supply us with specified quantities of our cell therapy products and product candidates, manufactured in accordance with cGMP standards. We have certain non-cancellable minimum commitments to purchase products and services over the first five years of the Fujifilm MSA. The Fujifilm MSA does not obligate us to purchase products and product candidates exclusively from FDB. Other Research, Development and Manufacturing Agreements We may enter into other contracts in the normal course of business with clinical research organizations for clinical trials, with CMOs for product, product candidates and clinical supplies, and with other vendors for preclinical studies, supplies and other services for our operating purposes. These contracts generally provide for termination on notice. As of September 30, 2024 and December 31, 2023 , there were no material amounts accrued related to contract termination charges. Minimum Commitments We have non-cancellable minimum commitments for products and services, subject to agreements with a term of greater than one year with clinical research organizations and CMOs. We have incurred $ 3.0 million and $ 9.7 million against the minimum commitments for the three and nine months ended September 30, 2024 , respectively, and we incurred $ 2.8 million and $ 16.1 million against the minimum commitments for the three and nine months ended September 30, 2023, respectively. As of September 30, 2024, and December 31, 2023, we have accrued $ 3.2 million and $ 11.2 million, respectively, in research and development expenses related to minimum purchase commitments. Indemnification Agreements In the normal course of business, we enter into contracts and agreements that contain a variety of representations and warranties and provide for indemnification for certain liabilities. The exposure under these agreements is unknown because it involves claims that may be made against us in the future but have not yet been made. To date, we have not paid any claims or been required to defend any action related to our indemnification obligations. However, we may record charges in the future as a result of these indemnification obligations. We also have indemnification obligations to our directors and executive officers for specified events or occurrences, subject to some limits, while they are serving at our request in such capacities. There have been no claims to date, and we consider the fair value of these indemnification agreements to be minimal. Accordingly, we did no t record liabilities for these agreements as of September 30, 2024 and December 31, 2023. Contingencies From time to time, we may be involved in legal proceedings, as well as demands, claims and threatened litigation, which arise in the normal course of our business or otherwise. The ultimate outcome of any litigation is uncertain and unfavorable outcomes could have a negative impact on our results of operations and financial condition. Regardless of outcome, litigation can have an adverse impact on us because of the defense costs, diversion of management resources and other factors. We are not currently involved in any material legal proceedings. During the third quarter of 2024, MSK sent us a notice alleging that under the terms of our license agreements with MSK, MSK is entitled to $ 6.0 million of sub-licensing fees as a result of the $ 60.0 million we received from Pierre Fabre related to the Additional Territory upfront and milestone payments in 2024 pursuant to the A&R Commercialization Agreement. We do not believe we owe the $ 6.0 million to MSK under the terms of our license agreements with MSK and plan to enter into evaluative non-binding mediation with MSK to potentially resolve this disagreement. We paid the $ 6.0 million to MSK under protest in the third quarter of 2024 in order to proceed with the dispute process per the terms of the license agreements. We recorded this cost in research and development expenses on the condensed consolidated statements of operations and comprehensive income (loss) during the three and nine months ended September 30, 2024. There is no guarantee we will reach a favorable outcome in the mediation or on this matter and we may owe a portion of future milestones we receive from Pierre Fabre to MSK.

Stockholders' Equity (Deficit)

Stockholders' Equity (Deficit)	9 Months Ended
	Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]
Stockholders' Equity (Deficit)	9. Stockholders’ Equity (Deficit) Our authorized capital stock consists of 520,000,000 shares, all with a par value of $ 0.0001 per share, of which 500,000,000 shares are designated as common stock and 20,000,000 shares are designated as preferred stock. There were no shares of preferred stock outstanding as of September 30, 2024 and December 31, 2023. Equity Offerings As part of our July 2019 underwritten public offering, we issued and sold pre-funded warrants to purchase 117,801 shares of common stock in an underwritten public offering pursuant to a shelf registration on Form S-3. Each pre-funded warrant entitles the holder to purchase one share of common stock at an exercise price of $ 0.0025 per share and expires seven years from the date of issuance. These warrants were recorded as a component of stockholders’ equity (deficit) within additional paid-in capital. Per the terms of the warrant agreement, a holder of the outstanding warrants is not entitled to exercise any portion of any pre-funded warrant if, upon exercise of the warrant, the holder’s ownership (together with its affiliates) of our common stock or combined voting power of our securities beneficially owned by such holder (together with its affiliates) would exceed 9.99 % after giving effect to the exercise (the 2019 Warrant Maximum Ownership Percentage). Upon at least 61 days’ prior notice to us by the holder, any holder may increase or decrease the 2019 Warrant Maximum Ownership Percentage to any other percentage not to exceed 19.99 %. No July 2019 pre-funded warrants were exercised during the nine months ended September 30, 2024, and as of September 30, 2024 , pre-funded warrants to purchase 101,089 shares of our common stock from the July 2019 underwritten public offering were outstanding. As part of the May 2020 underwritten public offering, we issued and sold pre-funded warrants to purchase 114,678 shares of common stock in an underwritten public offering pursuant to a shelf registration on Form S-3. Additionally, as part of the December 2020 underwritten public offering, we issued and sold pre-funded warrants to purchase 81,632 shares of common stock in an underwritten public offering pursuant to a shelf registration on Form S-3. These warrants were recorded as a component of stockholders' equity (deficit) within additional paid-in capital. The terms of the pre-funded warrants issued and sold as part of the 2020 public offerings were similar to those issued and sold in 2019. No May 2020 or December 2020 pre-funded warrants were exercised during the nine months ended September 30, 2024. As of September 30, 2024 , 38,735 and 55,387 of the pre-funded warrants to purchase shares of our common stock issued and sold as part of the May 2020 and December 2020 underwritten public offerings, respectively, were outstanding. In January 2024, we issued and sold pre-funded warrants to purchase 1,090,907 shares of common stock at a price of $ 13.7475 per warrant in a registered direct offering pursuant to a shelf registration on Form S-3. The gross proceeds from this sale were $ 15.0 million, resulting in net proceeds of $ 14.8 million after deducting offering expenses payable by us. Each of the January 2024 pre-funded warrants issued entitles the holder to purchase one share of common stock at an exercise price of $ 0.0025 per share, with no expiration date. These warrants were recorded as a component of stockholders’ equity (deficit) within additional paid-in capital. Per the terms of the warrant agreement, a holder of the outstanding warrants is not entitled to exercise any portion of any pre-funded warrant if, upon exercise of the warrant, the holder’s ownership (together with its affiliates) of our common stock or combined voting power of our securities beneficially owned by such holder (together with its affiliates) would exceed 9.99 % after giving effect to the exercise (the January 2024 Warrant Maximum Ownership Percentage). Upon at least 61 days’ prior notice to us by the holder, any holder may increase or decrease the January 2024 Warrant Maximum Ownership Percentage to any other percentage not to exceed 19.99 %. In September 2024, we issued and sold 758,900 shares of common stock at an offering price of $ 8.25 per share and pre-funded warrants to purchase 3,604,780 shares of common stock at an offering price of $ 8.2499 per warrant in a registered direct offering pursuant to a shelf registration on Form S-3. The gross proceeds from this sale were $ 36.0 million, resulting in net proceeds of $ 35.8 million after deducting estimated offering expenses payable by us. Each of the September 2024 pre-funded warrants issued entitles the holder to purchase one share of common stock at an exercise price of $ 0.0001 per share, with no expiration date. These warrants were recorded as a component of stockholders’ equity (deficit) within additional paid-in capital. Per the terms of the warrant agreement, a holder of the outstanding warrants is not entitled to exercise any portion of any pre-funded warrant if, upon exercise of the warrant, the holder’s ownership (together with its affiliates) of our common stock or combined voting power of our securities beneficially owned by such holder (together with its affiliates) would exceed, at the holder's election, 4.99 %, 9.99 % or 19.99 % after giving effect to the exercise (the September 2024 Warrant Maximum Ownership Percentage). Upon at least 61 days’ prior notice to us by the holder, any holder may increase or decrease the September 2024 Warrant Maximum Ownership Percentage to any other percentage not to exceed 19.99 %. No January 2024 or September 2024 pre-funded warrants were exercised during the nine months ended September 30, 2024 and all 1,090,907 of the January 2024 pre-funded warrants and all 3,604,780 of the September 2024 pre-funded warrants remain outstanding as of September 30, 2024. ATM Facilities In the past three years, we have entered into two separate sales agreements with Cowen and Company, LLC (Cowen): in November 2021 (the 2021 ATM Facility) and in November 2023 (the 2023 ATM Facility). Each ATM facility provides or provided for the sale, in our sole discretion, of shares of our common stock having an aggregate offering price of up to $ 100.0 million, through Cowen, as our sales agent. We filed a registration statement on Form S-3 registering the offer and sale of these shares under the Securities Act (the 2023 Registration Statement). Upon the effectiveness of the 2023 Registration Statement, the 2021 ATM Facility was terminated, and no further sales can be made under the 2021 ATM Facility. The issuance and sale of these shares by us pursuant to the ATM facilities are deemed “at the market” offerings defined in Rule 415 under the Securities Act of 1933, as amended (the Securities Act), and were registered under the Securities Act. Commissions of up to 3.0 % are due on the gross sales proceeds of the common stock sold under each ATM facility. During the nine months ended September 30, 2023, we sold an aggregate of 5,917 shares of common stock under the 2021 ATM Facility, at an average price of $ 116.00 per share, for gross proceeds of $ 0.7 million and net proceeds of $ 0.6 million, after deducting commissions and other offering expenses payable by us. During the nine months ended September 30, 2024 , we sold an aggregate of 492,855 shares of common stock under the 2023 ATM Facility, at an average price of $ 19.23 per share, for gross proceeds of $ 9.5 million and net proceeds of $ 9.3 million, after deducting commissions and other offering expenses payable by us. As of September 30, 2024 , $ 88.7 million of common stock remained available to be sold under the 2023 ATM Facility, subject to certain conditions as specified in the sales agreement. Equity Incentive Plans In June 2024, we adopted the 2024 Equity Incentive Plan (the 2024 EIP), under which we may grant stock options, restricted stock awards (RSAs) and RSUs to employees, directors, consultants and other service providers. The 2014 Equity Incentive Plan, as amended (2014 EIP), expired March 31, 2024, after which no new awards can be granted from it. All awards granted prior to the 2014 EIP expiration continue to remain outstanding and governed in accordance with the rules set forth in the 2014 EIP and the terms of the associated grant notice. To the extent forfeited, cancelled or expired, certain awards granted under the 2014 EIP will become available for grant under the 2024 EIP. RSUs generally vest over two to four years . We have granted performance-based RSUs to certain of our employees that provide for the issuance of common stock if specified Company performance criteria related to tab-cel regulatory milestones are achieved. The number of performance-based RSUs that ultimately vests depends upon if and which performance criteria are achieved, as well as the employee’s continuous service, as defined in the 2014 EIP and 2024 EIP, through the date of vesting. The fair value of performance-based RSUs is determined as the closing stock price on the date of grant. Stock options are granted at prices no less than 100 % of the estimated fair value of the shares on the date of grant as determined by the board of directors, provided, however, that the exercise price of an option granted to a 10% shareholder cannot be less than 110% of the estimated fair value of the shares on the date of grant. Options granted generally vest over three or four years and expire in seven to ten years . We have granted performance-based stock options to certain of our employees that provide for the issuance of a right to purchase a share of common stock if specified Company performance criteria related to tab-cel regulatory milestones are achieved. The vesting of performance-based stock options depends upon if and when the performance criteria are achieved, as well as the employee’s continuous service as defined in the 2014 EIP and 2024 EIP, through the date of vesting. As of September 30, 2024, a total of 695,311 shares of common stock were reserved for issuance under the 2014 EIP, of which all were subject to outstanding options and RSUs, including performance-based awards. As of September 30, 2024, a total of 343,901 shares of common stock were reserved for issuance under the 2024 EIP, of which all were available for grant. In February 2018, we adopted the 2018 Inducement Plan (the Inducement Plan), under which we may grant options, stock appreciation rights, RSAs and RSUs to new employees. In November 2020, September 2021 and June 2022 we amended the Inducement Plan to reserve an additional 60,000 shares of the Company’s common stock for issuance under the Inducement Plan in each case. As of September 30, 2024, 172,819 shares of common stock were reserved for issuance under the Inducement Plan, of which 119,857 shares were available for future grant and 52,962 shares were subject to outstanding options and RSUs. In May 2014, we adopted the 2014 Employee Stock Purchase Plan (2014 ESPP), which permits eligible employees to purchase common stock at a discount through payroll deductions during defined offering periods. Following stockholder approval, in June 2024, we amended the 2014 ESPP to increase the number of shares of our common stock available for issuance under the 2014 ESPP by 40,000 shares. Restricted Stock Units The following is a summary of RSU activity under our 2014 EIP and Inducement Plan: RSUs Shares Weighted Balance as of December 31, 2023 250,709 $ 158.00 Granted 545,490 $ 13.80 Forfeited ( 57,303 ) $ 94.14 Vested ( 221,496 ) $ 81.00 Balance as of September 30, 2024 517,400 $ 46.01 As of September 30, 2024 , there was $ 18.7 million of unrecognized stock-based compensation expense related to RSUs that is expected to be recognized over a weighted average period of 1.5 years. This excludes unrecognized stock-based compensation expense for performance-based RSUs that were deemed not probable of vesting in accordance with U.S. GAAP. Stock Options The following is a summary of stock option activity under our 2014 EIP and Inducement Plan: Shares Weighted Weighted Aggregate Balance as of December 31, 2023 428,786 $ 290.75 6.5 $ — Granted 16,500 11.00 — — Exercised — — — — Forfeited or expired ( 169,413 ) 357.61 — — Balance as of September 30, 2024 275,873 $ 232.96 7.0 $ — Aggregate intrinsic value represents the difference between the closing stock price of our common stock on September 30, 2024 and the exercise price of outstanding, in-the-money options. As of September 30, 2024 , there was $ 7.0 million of unrecognized stock-based compensation expense related to stock options that is expected to be recognized over a weighted average period of 1.3 years. This excludes unrecognized stock-based compensation expense for performance-based stock options that were deemed not probable of vesting in accordance with U.S. GAAP. Reserved Shares The following shares of common stock were reserved for future issuance under our equity incentive plans as of September 30, 2024: Total Shares 2014 Equity Incentive Plan 695,311 2018 Inducement Plan 172,819 2024 Equity Incentive Plan 343,901 2014 Employee Stock Purchase Plan 40,190 Total reserved shares of common stock 1,252,221 Stock-based Compensation Expense The following is a summary of stock-based compensation expense for the periods presented: Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 (in thousands) (in thousands) Research and development $ 2,877 $ 6,758 $ 10,904 $ 20,723 General and administrative 3,545 4,385 10,251 14,736 Total stock-based compensation expense $ 6,422 $ 11,143 $ 21,155 $ 35,459

Supplemental Balance Sheet Info

Supplemental Balance Sheet Information	9 Months Ended
	Sep. 30, 2024
Supplemental Balance Sheet Information [Abstract]
Supplemental Balance Sheet Information	10. Supplemental Balance Sheet Information Inventories Inventories consisted of the following as of each period end: September 30, December 31, 2024 2023 (in thousands) Raw Materials $ 1,652 $ 2,335 Work-in-process 12,328 7,371 Total inventories $ 13,980 $ 9,706 Property and equipment, net Property and equipment consisted of the following as of each period end: September 30, December 31, 2024 2023 (in thousands) Leasehold improvements $ 930 $ 904 Lab equipment 15,553 15,540 Machinery and equipment 572 572 Computer equipment and software 1,381 1,279 Furniture and fixtures 1,272 1,272 Construction in progress — 158 Property and equipment, gross 19,708 19,725 Less: accumulated depreciation ( 18,047 ) ( 15,869 ) Property and equipment, net $ 1,661 $ 3,856 Depreciation expense was $ 0.6 million and $ 0.9 million for the three months ended September 30, 2024 and 2023 , respectively, and $ 2.2 million and $ 2.8 million for the nine months ended September 30, 2024 and 2023, respectively. Other current liabilities Other current liabilities consisted of the following as of each period end: September 30, December 31, 2024 2023 (in thousands) Accrued operating expenses $ 8,059 $ 19,007 Current portion of operating lease liabilities 13,652 11,264 Current portion of finance lease liabilities 1,006 915 Other accrued liabilities 927 640 Total other current liabilities $ 23,644 $ 31,826

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited interim condensed consolidated financial statements include the accounts of Atara and its wholly owned subsidiaries and have been prepared in accordance with U.S. generally accepted accounting principles (U.S. GAAP) and the requirements of the Securities and Exchange Commission (SEC) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP can be condensed or omitted. These unaudited interim condensed consolidated financial statements should therefore be read in conjunction with the audited consolidated financial statements and notes for the year ended December 31, 2023, included in the Company’s Annual Report on Form 10-K filed with the SEC on March 28, 2024. In the opinion of management, the condensed consolidated financial statements reflect all adjustments, consisting only of normal recurring adjustments, which are necessary for a fair presentation of the Company’s condensed consolidated financial statements. The results of operations for any interim period are not necessarily indicative of the results to be expected for the full year or any other future period. The condensed consolidated balance sheet as of December 31, 2023 has been derived from audited consolidated financial statements at that date but does not include all of the information required by U.S. GAAP for complete consolidated financial statements.
Liquidity and Going Concern	Liquidity Risk We have incurred significant operating losses since inception and have relied primarily on public and private equity financings and receipts from commercialization and license and collaboration agreements to fund our operations. As we continue to incur losses, our transition to profitability will depend on the successful development, approval and commercialization of product candidates and on the achievement of sufficient revenues to support our cost structure. We may never achieve sustained operating cash inflows or profitability. Going Concern We have incurred operating losses since inception and we expect that existing cash, cash equivalents and short-term investments as of September 30, 2024, will not be sufficient to fund our planned operations for at least 12 months from the date of issuance of these condensed consolidated financial statements. Although we anticipate the receipt of certain payments from the amended and restated Pierre Fabre Commercialization Agreement in 2025, such payments are contingent upon the approval of the tab-cel BLA, which is dependent upon the completion of specific development and regulatory activities by us and actions taken by third parties, and are, therefore, uncertain at this time. To alleviate the conditions that raise substantial doubt about our ability to continue as a going concern, we plan to secure additional capital, potentially through a combination of public or private security offerings; use of our ATM facility as described in Note 9; and/or strategic transactions. We may need to raise additional funding as required based on the status of our development programs and our projected cash flows. Although we have been successful in raising capital in the past, and expect to continue to raise capital as required, there is no assurance that we will be successful in obtaining sufficient funding on terms acceptable to us to fund continuing operations, if at all, or identify and enter into any strategic transactions that will provide the capital that we will require. If we are unable to obtain sufficient funding on acceptable terms, we could be forced to delay, limit, reduce or terminate preclinical studies, clinical studies or other development activities for one or more of our product candidates, which could have a material adverse effect on our business, results of operations, and financial condition. Accordingly, we have concluded that substantial doubt exists with respect to our ability to continue as a going concern for at least 12 months after the issuance of the accompanying condensed consolidated financial statements. The condensed consolidated financial statements do not include any adjustments that might result from the outcome of this uncertainty.
Reverse Stock Split	June 2024 Reverse Stock Split At our annual meeting of stockholders held on June 10, 2024, the stockholders of Atara approved a proposal to authorize our Board of Directors (the Board) to amend our Amended and Restated Certificate of Incorporation to effect a reverse stock split. The Board approved the reverse stock split on June 10, 2024 and, on June 20, 2024, we effected a 1-for-25 reverse stock split of our common stock. The par value and the authorized shares of the common stock were not adjusted as a result of the reverse stock split. All equity related information including per share amounts for all periods presented in these condensed consolidated financial statements and the notes thereto have been adjusted retroactively, where applicable, to reflect the effect of this reverse stock split.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates, assumptions and judgments that affect the amounts reported in the financial statements and accompanying notes. Significant estimates relied upon in preparing these financial statements include estimates related to revenue recognition, accrued research and development expenses, stock-based compensation expense, income taxes and the liability related to the sale of future revenues. Actual results could differ materially from those estimates.
Recent Accounting Pronouncements	Recent Accounting Pronouncements We consider the applicability and impact of any recent Accounting Standards Update (ASU) issued by the Financial Accounting Standards Board (FASB). Other than the ASUs listed below, all other ASUs were assessed and determined to be either not applicable to Atara or are expected to have minimal impact on our condensed consolidated financial statements. In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. The amendment requires disclosure of significant segment expenses that are regularly provided to the chief operating decision maker and included within each reported measure of segment profit or loss, an amount and description of its composition for other segment items, and interim disclosures of a reportable segment’s profit or loss and assets. Additionally, all disclosure requirements under the guidance are required for public entities with a single reportable segment and are to be applied retrospectively to all periods presented. We will adopt the amendments effective for the fiscal year ending December 31, 2024, and for interim periods within fiscal years beginning January 1, 2025. The adoption of ASU 2023-07 will not have a material impact on our consolidated financial statements and will consist of the inclusion of additional disclosures related to our single reportable segment in the notes to the consolidated financial statements. The amendments in this update do not affect the recognition, measurement or financial statement presentation of expenses. In December 2023, the FASB issued ASU No. 2023-09 Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which requires enhancements to certain income tax disclosures, most notably the income tax rate reconciliation and income taxes paid. We will adopt the amendments effective for the fiscal year ending December 31, 2025. We do not expect the adoption of this standard will have a material impact on our disclosures.

Net Loss per Common Share (Tabl

Net Loss per Common Share (Tables)	9 Months Ended
	Sep. 30, 2024
Earnings Per Share [Abstract]
Antidilutive Securities Excluded From Computation of Diluted Net Loss per Common Share	The following table represents the potential common shares issuable pursuant to outstanding securities as of the related period end dates that were excluded from the computation of diluted net loss per common share, as their inclusion would have an antidilutive effect: As of September 30, 2024 2023 Unvested RSUs 495,996 338,244 Vested and unvested options 263,788 491,521 ESPP share purchase rights 34,511 18,942 Total 794,295 848,707

Financial Instruments (Tables)

Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2024
Financial Instruments Disclosure [Abstract]
Summary of Estimated Fair Value and Related Valuation Input Hierarchy of Available-for-Sale Securities	The following tables summarize the estimated fair value and related valuation input hierarchy of our available-for-sale securities as of each period end: Total Total Total Total Amortized Unrealized Unrealized Estimated As of September 30, 2024: Input Level Cost Gain Loss Fair Value (in thousands) Money market funds Level 1 $ 23,334 $ — $ — $ 23,334 U.S. Treasury obligations Level 2 40,472 24 — $ 40,496 Corporate debt obligations Level 2 1,497 — ( 2 ) $ 1,495 Commercial paper Level 2 495 — — $ 495 Total available-for-sale securities 65,798 24 ( 2 ) 65,820 Less: amounts classified as cash equivalents ( 45,077 ) ( 7 ) — ( 45,084 ) Amounts classified as short-term investments $ 20,721 $ 17 $ ( 2 ) $ 20,736 Total Total Total Total Amortized Unrealized Unrealized Estimated As of December 31, 2023: Input Level Cost Gain Loss Fair Value (in thousands) Money market funds Level 1 $ 14,376 $ — $ — $ 14,376 U.S. Treasury obligations Level 2 9,928 1 — 9,929 Corporate debt obligations Level 2 26,089 — ( 205 ) 25,884 Total available-for-sale securities 50,393 1 ( 205 ) 50,189 Less: amounts classified as cash equivalents ( 24,304 ) ( 1 ) — ( 24,305 ) Amounts classified as short-term investments $ 26,089 $ — $ ( 205 ) $ 25,884
Amortized Cost and Fair Value of Available for Sale Securities by Contractual Maturity	The amortized cost and fair value of our available-for-sale securities by contractual maturity were as follows: As of September 30, 2024 As of December 31, 2023 Amortized Estimated Amortized Estimated Cost Fair Value Cost Fair Value (in thousands) (in thousands) Maturing within one year $ 65,798 $ 65,820 $ 50,393 $ 50,189 Maturing in one to five years — — — — Total available-for-sale securities $ 65,798 $ 65,820 $ 50,393 $ 50,189
Reconciliation of Cash, Cash Equivalents and Restricted Cash	The following table provides a reconciliation of cash, cash equivalents and restricted cash within the condensed consolidated balance sheets that sum to the total of the same such amounts in the condensed consolidated statement of cash flows: September 30, December 31, 2024 2023 (in thousands) Cash and cash equivalents $ 46,453 $ 25,841 Restricted cash – short term 146 146 Total cash, cash equivalents and restricted cash $ 46,599 $ 25,987

Out-license Agreements (Tables)

Out-license Agreements (Tables)	9 Months Ended
	Sep. 30, 2024
License Collaboration And Manufacturing Agreements [Abstract]
Schedule of Deferred Revenue Activity	Deferred revenue activity related to commercialization revenue for the nine months ended September 30, 2024 was as follows: (in thousands) Deferred revenue, January 1, 2024 $ 115,395 Additions 94,520 Recognized into commercialization revenue ( 93,101 ) Deferred revenue September 30, 2024 116,814 Less: deferred revenue – current portion ( 116,344 ) Deferred revenue – long-term, September 30, 2024 $ 470

Liability Related to the Sale_2

Liability Related to the Sale of Future Revenues (Tables)	9 Months Ended
	Sep. 30, 2024
Liability for Future Policy Benefit, after Reinsurance [Abstract]
Schedule of changes in liability of sales revenues Agreement Table Text Block	The following table presents the changes in the liability related to the sale of future revenues under the HCRx Agreement for the nine months ended September 30, 2024: (in thousands) Liability related to sale of future revenues as of January 1, 2024 $ 35,076 Accretion of interest expense on liability related to sale of future revenues 3,180 Amortization of debt discount and debt issuance costs 52 Repayment of the liability ( 132 ) Liability related to the sale of future revenues as of September 30, 2024 38,176 Less: current portion classified within other accrued liabilities ( 592 ) Liability related to sale of future revenues - long-term $ 37,584

Property and Equipment (Tables)

Property and Equipment (Tables)	9 Months Ended
	Sep. 30, 2024
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment consisted of the following as of each period end: September 30, December 31, 2024 2023 (in thousands) Leasehold improvements $ 930 $ 904 Lab equipment 15,553 15,540 Machinery and equipment 572 572 Computer equipment and software 1,381 1,279 Furniture and fixtures 1,272 1,272 Construction in progress — 158 Property and equipment, gross 19,708 19,725 Less: accumulated depreciation ( 18,047 ) ( 15,869 ) Property and equipment, net $ 1,661 $ 3,856

Restructuring (Tables)

Restructuring (Tables)	9 Months Ended
	Sep. 30, 2024
Restructuring and Related Activities [Abstract]
Summarizes of future termination benefit payments	The following is a summary of restructuring charges associated with the reductions in force for the periods presented: Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 (in thousands) (in thousands) Research and development expense $ — $ — $ 3,750 $ — General and administrative expense — — 1,357 45 Total restructuring charges $ — $ — $ 5,107 $ 45
Restructuring of Labiality Activity	The following restructuring liability activity was recorded in connection with the reductions in force for the nine months ended September 30, 2024: (in thousands) Liability balance, January 1, 2024 $ 4,923 Restructuring charges 5,107 Cash payments ( 9,157 ) Non-cash settlements/adjustments ( 666 ) Liability balance, September 30, 2024 $ 207

Stockholders' Equity (Deficit)

Stockholders' Equity (Deficit) (Tables)	9 Months Ended
	Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]
Summary of RSU Activity	The following is a summary of RSU activity under our 2014 EIP and Inducement Plan: RSUs Shares Weighted Balance as of December 31, 2023 250,709 $ 158.00 Granted 545,490 $ 13.80 Forfeited ( 57,303 ) $ 94.14 Vested ( 221,496 ) $ 81.00 Balance as of September 30, 2024 517,400 $ 46.01
Summary of Stock Option Activity	The following is a summary of stock option activity under our 2014 EIP and Inducement Plan: Shares Weighted Weighted Aggregate Balance as of December 31, 2023 428,786 $ 290.75 6.5 $ — Granted 16,500 11.00 — — Exercised — — — — Forfeited or expired ( 169,413 ) 357.61 — — Balance as of September 30, 2024 275,873 $ 232.96 7.0 $ —
Schedule of Common Stock Reserved for Future Issuance Under Equity Incentive Plans	The following shares of common stock were reserved for future issuance under our equity incentive plans as of September 30, 2024: Total Shares 2014 Equity Incentive Plan 695,311 2018 Inducement Plan 172,819 2024 Equity Incentive Plan 343,901 2014 Employee Stock Purchase Plan 40,190 Total reserved shares of common stock 1,252,221
Schedule of Stock-based Compensation, Related to Employee and Nonemployee Stock Awards	Stock-based Compensation Expense The following is a summary of stock-based compensation expense for the periods presented: Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 (in thousands) (in thousands) Research and development $ 2,877 $ 6,758 $ 10,904 $ 20,723 General and administrative 3,545 4,385 10,251 14,736 Total stock-based compensation expense $ 6,422 $ 11,143 $ 21,155 $ 35,459

Supplemental Balance Sheet In_2

Supplemental Balance Sheet Information (Tables)	9 Months Ended
	Sep. 30, 2024
Supplemental Balance Sheet Information [Abstract]
Schedule of Inventories	Inventories consisted of the following as of each period end: September 30, December 31, 2024 2023 (in thousands) Raw Materials $ 1,652 $ 2,335 Work-in-process 12,328 7,371 Total inventories $ 13,980 $ 9,706
Schedule of Property and Equipment	Property and equipment consisted of the following as of each period end: September 30, December 31, 2024 2023 (in thousands) Leasehold improvements $ 930 $ 904 Lab equipment 15,553 15,540 Machinery and equipment 572 572 Computer equipment and software 1,381 1,279 Furniture and fixtures 1,272 1,272 Construction in progress — 158 Property and equipment, gross 19,708 19,725 Less: accumulated depreciation ( 18,047 ) ( 15,869 ) Property and equipment, net $ 1,661 $ 3,856
Schedule of Other Current Liabilities	Other current liabilities consisted of the following as of each period end: September 30, December 31, 2024 2023 (in thousands) Accrued operating expenses $ 8,059 $ 19,007 Current portion of operating lease liabilities 13,652 11,264 Current portion of finance lease liabilities 1,006 915 Other accrued liabilities 927 640 Total other current liabilities $ 23,644 $ 31,826

Description of Business (Detail

Description of Business (Detail) - USD ($) $ in Millions	1 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2022	Sep. 30, 2024	Dec. 31, 2022
License Collaboration And Manufacturing Agreements [Line Items]
Entity incorporation state		DE
Entity incorporation date		Aug. 01, 2012
HCRx Agreement [Member]
License Collaboration And Manufacturing Agreements [Line Items]
Proceeds from sale of future royalties, gross	$ 31		$ 31
Minimum cash repayment		185%
Maximum cash repayment		250%

Net Loss per Common Share - Ant

Net Loss per Common Share - Antidilutive Securities Excluded From Computation of Diluted Net Loss per Common Share (Detail) - shares	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	794,295	848,707
Unvested RSUs
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	495,996,000	338,244
Employee Stock Option
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	263,788,000	491,521
ESPP Share Purchase Rights
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	34,511,000	18,942

Financial Instruments - Summary

Financial Instruments - Summary of Estimated Fair Value and Related Valuation Input Hierarchy of Available-for-Sale Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Schedule of Available-for-sale Securities [Line Items]
Total Fair Value	$ 65,820	$ 50,189
Fair Value, Measurements, Recurring
Schedule of Available-for-sale Securities [Line Items]
Total Amortized Cost	65,798	50,393
Total Unrealized Gain	24	1
Total Unrealized Loss	(2)	(205)
Total Fair Value	65,820	50,189
Amounts Classified As Cash Equivalents | Fair Value, Measurements, Recurring
Schedule of Available-for-sale Securities [Line Items]
Total Amortized Cost	(45,077)	(24,304)
Total Unrealized Gain	(7)	(1)
Total Unrealized Loss	0	0
Total Fair Value	(45,084)	(24,305)
Amounts Classified As Short-Term Investments | Fair Value, Measurements, Recurring
Schedule of Available-for-sale Securities [Line Items]
Total Amortized Cost	20,721	26,089
Total Unrealized Gain	17	0
Total Unrealized Loss	(2)	(205)
Total Fair Value	20,736	25,884
Level 1 | Money Market Funds | Fair Value, Measurements, Recurring
Schedule of Available-for-sale Securities [Line Items]
Total Amortized Cost	23,334	14,376
Total Unrealized Gain	0	0
Total Unrealized Loss	0	0
Total Fair Value	23,334	14,376
Level 2 | U.S. Treasury Obligations | Fair Value, Measurements, Recurring
Schedule of Available-for-sale Securities [Line Items]
Total Amortized Cost	40,472	9,928
Total Unrealized Gain	24	1
Total Unrealized Loss	0	0
Total Fair Value	40,496	9,929
Level 2 | Corporate Debt Obligations | Fair Value, Measurements, Recurring
Schedule of Available-for-sale Securities [Line Items]
Total Amortized Cost	1,497	26,089
Total Unrealized Gain	0	0
Total Unrealized Loss	(2)	(205)
Total Fair Value	1,495	$ 25,884
Level 2 | Commercial Paper | Fair Value, Measurements, Recurring
Schedule of Available-for-sale Securities [Line Items]
Total Amortized Cost	495
Total Unrealized Gain	0
Total Unrealized Loss	0
Total Fair Value	$ 495

Financial Instruments - Amortiz

Financial Instruments - Amortized Cost and Fair Value of Available-for-Sale Securities by Contractual Maturity (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Amortized cost
Maturing within one year, Amortized cost	$ 65,798	$ 50,393
Maturing in one to five years, Amortized cost	0	0
Total available-for-sale securities, Amortized cost	65,798	50,393
Estimated Fair value
Maturing within one year, Estimated fair value	65,820	50,189
Maturing in one to five years, Estimated fair value	0	0
Total Fair Value	$ 65,820	$ 50,189

Financial Instruments - Additio

Financial Instruments - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Financial Instruments Disclosure [Abstract]
Accrued interest receivable	$ 0.1		$ 0.1		$ 0.3
Write off, of accrued interest receivable	$ 0	$ 0	$ 0	$ 0

Financial Instruments - Reconci

Financial Instruments - Reconciliation of Cash, Cash Equivalents and Restricted Cash (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022
Financial Instruments Disclosure [Abstract]
Cash and cash equivalents	$ 46,453	$ 25,841
Restricted cash - short term	146	146
Total cash, cash equivalents and restricted cash	$ 46,599	$ 25,987	$ 64,937	$ 93,088

Property and Equipment - Schedu

Property and Equipment - Schedule of Property and Equipment (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 19,708	$ 19,725
Less: accumulated depreciation and amortization	(18,047)	(15,869)
Property and equipment, net	1,661	3,856
Leasehold Improvements [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	930	904
Machinery and Equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	572	572
Furniture and Fixtures [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,272	1,272
Construction in Progress [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 0	$ 158

Property and Equipment - Additi

Property and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Property, Plant and Equipment, Net, by Type [Abstract]
Depreciation and amortization expense	$ 3,951	$ 3,624

Out-license Agreements - Schedu

Out-license Agreements - Schedule of Deferred Revenue Activity (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
License Collaboration And Manufacturing Agreements [Line Items]
Deferred revenue - long-term, September 30, 2024	$ 470	$ 37,562
Commercialization Revenue [Member]
License Collaboration And Manufacturing Agreements [Line Items]
Deferred revenue, January 1, 2024	115,395
Additions	94,520
Recognized into commercialization revenue	(93,101)
Deferred revenue September 30, 2024	116,814
Less: deferred revenue - current portion	(116,344)
Deferred revenue - long-term, September 30, 2024	$ 470

Out-license Agreements - Additi

Out-license Agreements - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended						3 Months Ended		9 Months Ended		12 Months Ended
	Aug. 31, 2024	Jul. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Oct. 31, 2021	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2022	Mar. 31, 2024
License Collaboration And Manufacturing Agreements [Line Items]
License and collaboration revenue							$ 0	$ 118	$ 0	$ 624
Revenue recognition, performance satisfied or partially satisfied prior period							8,800		8,800
Deferred revenue, revenue recognized									31,400
Pierre Fabre Commercialization Agreement
License Collaboration And Manufacturing Agreements [Line Items]
Upfront cash payment received			$ 20,000			$ 45,000
Milestone payments				$ 40,000							$ 40,000	$ 20,000
Additional milestone payments		$ 20,000
Royalty eligible to receive term after first commercial sale			12 years			12 years
Payments received from sale of inventory	$ 15,500
Determined upfront payment constituted entire consideration included in transaction price						$ 45,000
Development or sales-based milestone payments earned or received				40,000	$ 30,000
Pierre Fabre Commercialization Agreement | Maximum [Member]
License Collaboration And Manufacturing Agreements [Line Items]
Aggregate milestone payments entitle to receive upon achieving certain regulatory and commercial milestones						$ 308,000	580,000		$ 580,000
HCRx Agreement [Member]
License Collaboration And Manufacturing Agreements [Line Items]
Proceeds from sale of future royalties, gross				$ 31,000							$ 31,000
Minimum cash repayment									185%
Maximum cash repayment									250%
AR Commercialization Agreement [Member]
License Collaboration And Manufacturing Agreements [Line Items]
Additional Upfront Payment Included inTransaction Price							20,000		$ 20,000
Regulatory Milestone		$ 20,000										$ 20,000
Costs Incurred Relatedto Performance Obligations Includedin R&D							$ 11,100		$ 33,800

Liability Related to the Sale_3

Liability Related to the Sale of Future Revenues - Schedule of Liability Related to the Sale of Future Royalties (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Liability for Future Policy Benefit, after Reinsurance [Abstract]
Liability related to sale of future revenues as of January 1, 2024	$ 35,076
Accretion of interest expense on liability related to sale of future revenues	3,180	$ 3,729
Amortization of debt discount and debt issuance costs	52
Repayment of the liability	(132)
Liability related to the sale of future revenues as of June 30, 2024	38,176
Less: current portion classified within other accrued liabilities	(592)
Liability related to sale of future revenues - long-term	$ 37,584		$ 34,623

Liability Related to the Sale_4

Liability Related to the Sale of Future Revenues (Additional Information) (Details) - USD ($) $ in Thousands	1 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2022	Sep. 30, 2024	Dec. 31, 2022
Liability for Future Policy Benefit, Activity [Line Items]
Payments for royalties		$ 132
HCRx Agreement [Member]
Liability for Future Policy Benefit, Activity [Line Items]
Minimum cash repayment		185%
Maximum cash repayment		250%
Cash Payment		$ 9,000
Proceeds from sale of future royalties, gross	$ 31,000		$ 31,000
Number Of transaction cost	$ 400
Interest rate of royalties, percentage		11%

Leases - Schedule of Maturities

Leases - Schedule of Maturities of Lease Liabilities Under Operating and Finance Leases (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Leases [Abstract]
Other current liabilities	$ 13,652	$ 11,264
Operating lease liabilities - long-term	35,243	45,693
Other current liabilities	$ 1,006	$ 915

Leases - Summary of Other Infor

Leases - Summary of Other Information Related to Leases (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
CashPaidForAmountsIncludedInMeasurementOfLeaseLiabilitiesAbstract
Financing cash flows for finance leases	$ 657	$ 732

Restructuring (Additional Infor

Restructuring (Additional Information) (Details) - USD ($) $ in Millions	Sep. 30, 2024	Jan. 31, 2024	Nov. 30, 2023
Restructuring and Related Activities [Abstract]
Reduction in current workforce		25%	30%
Supplemental Unemployment Benefits, Severance Benefits		$ 5.1	$ 6.7
Restructuring Liability	$ 0.2

Restructuring - Summary of futu

Restructuring - Summary of future termination benefit payments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	$ 0	$ 0	$ 5,107	$ 45
General and administrative
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	0	0	1,357	45
Research and development
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	$ 0	$ 0	$ 3,750	$ 0

Restructuring - Restructuring l

Restructuring - Restructuring liability activity (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Restructuring and Related Activities [Abstract]
Liability balance, January 1, 2024			$ 4,923
Restructuring charges	$ 0	$ 0	5,107	$ 45
Cash payments			(9,157)
Non-cash settlements/adjustments			(666)
Liability balance, September 30, 2024	$ 207		$ 207

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
	Apr. 04, 2022	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Loss Contingencies [Line Items]
Contractual obligations due to Bayer, MSK and QIMR		$ 0		$ 0		$ 0
Minimum commitments Expense		3	$ 2.8	9.7	$ 16.1
Accrued termination charges		0		0		0
Liabilities related to indemnification agreements		0		0		0
Sub Licensing Fees		6		6
Minimum purchase commitments accrued		3.2		$ 3.2		$ 11.2
Fujifilm Master Services and Supply Agreement
Loss Contingencies [Line Items]
Supply agreement maximum extension term	10 years
MSK License Agreements
Loss Contingencies [Line Items]
Sub Licensing Fees		6
Upfront and milestone payments		$ 60

Stockholders' Equity (Deficit_2

Stockholders' Equity (Deficit) - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions				1 Months Ended		3 Months Ended	9 Months Ended
	Sep. 03, 2024	Jan. 02, 2024	Apr. 25, 2022	Sep. 30, 2024	Jan. 31, 2024	Sep. 30, 2024	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2020	May 31, 2020	Jul. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Authorized capital stock				520,000,000		520,000,000	520,000,000		520,000,000
Common stock, par value				$ 0.0001		$ 0.0001	$ 0.0001		$ 0.0001
Common stock, shares authorized				500,000,000		500,000,000	500,000,000		500,000,000
Preferred stock, par value				$ 0.0001		$ 0.0001	$ 0.0001		$ 0.0001
Preferred stock, shares authorized				20,000,000		20,000,000	20,000,000		20,000,000
Preferred stock, shares outstanding				0		0	0		0
Shares Issued, Price per Share	$ 8.25
Common stock, shares issued	758,900
Common stock value remaining to be sold				$ 88.7		$ 88.7	$ 88.7
Shares of common stock, reserved for issuance				1,252,221		1,252,221	1,252,221
2014 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of common stock, reserved for issuance				695,311		695,311	695,311
2024 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of common stock, reserved for issuance				343,901		343,901	343,901
Additional shares of common stock, reserved for issuance				40,000		40,000	40,000
Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of common stock, reserved for issuance				172,819		172,819	172,819
Outstanding options and RSUs				52,962		52,962	52,962
Aggregate number of awards available for grant to be issued				119,857		119,857	119,857
Additional shares of common stock, reserved for issuance				60,000		60,000	60,000
Restricted Stock Units (RSUs) | 2014 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation weighted average recognition period							1 year 6 months
Unrecognized stock-based compensation				$ 18.7		$ 18.7	$ 18.7
Employee Stock Option | 2014 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation weighted average recognition period							1 year 3 months 18 days
Unrecognized stock-based compensation				$ 7		$ 7	$ 7
Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of employees purchase price of common stock							100%
Minimum [Member] | Employees And Non Employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation, vesting period							3 years
Stock option granted description terms							the exercise price of an option granted to a 10% shareholder cannot be less than 110% of the estimated fair value of the shares on the date of grant. Options granted generally vest over three or four years and expire in seven to ten years.
Share based compensation award expiration period							7 years
Maximum [Member] | Restricted Stock Units (RSUs) | From Date Of Grant
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation, vesting period								4 years
Maximum [Member] | Employees And Non Employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation, vesting period							4 years
Share based compensation award expiration period							10 years
Warrant
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of warrants issued	3,604,780
Warrant | May 2020 Warrants [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of warrants issued					1,090,907
Underwritten Public Offering | 2019 Warrants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrants outstanding									101,089
Warrants outstanding									101,089
Underwritten Public Offering | January 2024 Warrants [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrants outstanding				1,090,907		1,090,907	1,090,907
Warrants outstanding				1,090,907		1,090,907	1,090,907
Underwritten Public Offering | Warrant
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of warrants issued												117,801
Number of securities called by each warrant				1,000	1,000	1,000	1,000					1
Warrants, exercise price				$ 0.0001	$ 0.0025	$ 0.0001	$ 0.0001					$ 0.0025
Warrants, term			7 years
Maximum ownership Percentage				9.99%	9.99%		9.99%
Warrants outstanding				3,604,780		3,604,780	3,604,780
Warrants outstanding				3,604,780		3,604,780	3,604,780
Warrants, exercise price				$ 0.0001	$ 0.0025	$ 0.0001	$ 0.0001					$ 0.0025
Underwritten Public Offering | Warrant | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Maximum ownership Percentage				4.99%
Prior notice period			61 days	61 days	61 days
Underwritten Public Offering | Warrant | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Maximum ownership Percentage				19.99%	19.99%	19.99%
Underwritten Public Offering | Warrant | December 2020 Warrants [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of warrants issued										81,632
Warrants outstanding				55,387		55,387	55,387
Warrants outstanding				55,387		55,387	55,387
Underwritten Public Offering | Warrant | May 2020 Warrants [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of warrants issued											114,678
Warrants outstanding				38,735		38,735	38,735
Warrants outstanding				38,735		38,735	38,735
Direct Registered Offering
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrants, exercise price				$ 8.2499		$ 8.2499	$ 8.2499
Warrants, exercise price				$ 8.2499		$ 8.2499	$ 8.2499
Shares Issued, Price per Share					$ 13.7475
Proceeds from sale of pre-funded warrants to purchase common stock, gross	$ 36	$ 15
Proceeds from sale of pre-funded warrants to purchase common stock, net	$ 35.8	$ 14.8
At The Market Offering | Cowen
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock aggregate offering price				$ 100		$ 100	$ 100
Percentage of commission to be paid on gross sales proceeds of common stock sold							3%
Common stock, shares issued							492,855	5,917
Common stock average price							$ 19.23	$ 116
Proceeds from sale of pre-funded warrants to purchase common stock, gross							$ 9.5	$ 0.7
Proceeds from sale of pre-funded warrants to purchase common stock, net							$ 9.3	$ 0.6

Stockholders' Equity (Deficit_3

Stockholders' Equity (Deficit) - Summary of RSU Activity (Detail) - Unvested RSUs	9 Months Ended
	Sep. 30, 2024 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Balance as of December 31, 2023 | shares	250,709
Shares, Granted | shares	545,490
Shares, Forfeited | shares	(57,303)
Shares, Vested | shares	(221,496)
Balance as of September 30, 2024 | shares	517,400
Balance as of December 31, 2023 | $ / shares	$ 158
Weighted Average Grant Date Fair Value, Granted | $ / shares	13.8
Weighted Average Grant Date Fair Value, Forfeited | $ / shares	94.14
Weighted Average Grant Date Fair Value, Vested | $ / shares	81
Balance as of September 30, 2024 | $ / shares	$ 46.01

Stockholders' Equity (Deficit_4

Stockholders' Equity (Deficit) - Summary of Stock Option Activity (Detail) - 2014 EIP and Inducement Plan - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Outstanding, Shares, beginning balance	428,786
Granted, Shares	16,500
Exercised, Shares	0
Forfeited or expired, Shares	(169,413)
Outstanding, Shares, ending balance	275,873	428,786
Outstanding, Weighted Average Exercise Price, beginning balance	$ 290.75
Granted, Weighted Average Exercise Price	11
Exercised, Weighted Average Exercise Price	0
Forfeited or expired, Weighted Average Exercise price	357.61
Outstanding, Weighted Average Exercise Price, ending balance	$ 232.96	$ 290.75
Outstanding, Weighted Average Remaining Contractual Term	7 years	6 years 6 months
Aggregate intrinsic value	$ 0	$ 0

Stockholders' Equity (Deficit_5

Stockholders' Equity (Deficit) - Schedule of Common Stock Reserved for Future Issuance Under Equity Incentive Plans (Detail)	Sep. 30, 2024 shares
Class Of Stock [Line Items]
Total reserved shares of common stock	1,252,221
2014 Equity Incentive Plan
Class Of Stock [Line Items]
Total reserved shares of common stock	695,311
2018 Inducement Plan
Class Of Stock [Line Items]
Total reserved shares of common stock	172,819
2024 Equity Incentive Plan
Class Of Stock [Line Items]
Total reserved shares of common stock	343,901
2014 Employee Stock Purchase Plan
Class Of Stock [Line Items]
Total reserved shares of common stock	40,190

Stockholders' Equity (Deficit_6

Stockholders' Equity (Deficit) - Schedule of Stock-based Compensation Related to All Employee And Non-employee Stock Awards (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 6,422	$ 11,143	$ 21,155	$ 35,459
Research and development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	2,877	6,758	10,904	20,723
General and administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 3,545	$ 4,385	$ 10,251	$ 14,736

Supplemental Balance Sheet In_3

Supplemental Balance Sheet Information (Additional Information) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Supplemental Balance Sheet Information [Abstract]
Depreciation expense	$ 0.6	$ 0.9	$ 2.2	$ 2.8

Supplemental Balance Sheet In_4

Supplemental Balance Sheet Information - Schedule of Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Supplemental Balance Sheet Information [Abstract]
Raw Materials	$ 1,652	$ 2,335
Work-in-process	12,328	7,371
Total inventories	$ 13,980	$ 9,706

Supplemental Balance Sheet In_5

Supplemental Balance Sheet Information - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Supplemental Balance Sheet Information [Line Items]
Property and equipment, gross	$ 19,708	$ 19,725
Less: accumulated depreciation and amortization	(18,047)	(15,869)
Property and equipment, net	1,661	3,856
Leasehold Improvements [Member]
Supplemental Balance Sheet Information [Line Items]
Property and equipment, gross	930	904
Lab equipment [Member]
Supplemental Balance Sheet Information [Line Items]
Property and equipment, gross	15,553	15,540
Machinery and Equipment [Member]
Supplemental Balance Sheet Information [Line Items]
Property and equipment, gross	572	572
Computer equipment and software [Member]
Supplemental Balance Sheet Information [Line Items]
Property and equipment, gross	1,381	1,279
Furniture and Fixtures [Member]
Supplemental Balance Sheet Information [Line Items]
Property and equipment, gross	1,272	1,272
Construction in Progress [Member]
Supplemental Balance Sheet Information [Line Items]
Property and equipment, gross	$ 0	$ 158

Supplemental Balance Sheet In_6

Supplemental Balance Sheet Information - Schedule of Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Supplemental Balance Sheet Information [Abstract]
Accrued operating expenses	$ 8,059	$ 19,007
Current portion of operating lease liabilities	13,652	11,264
Current portion of finance lease liabilities	1,006	915
Other accrued liabilities	927	640
Total other current liabilities	$ 23,644	$ 31,826