Fate Therapeutics (FATE) 10-K 26 Feb 24 2023 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Feb. 20, 2024	Jun. 30, 2023
Cover [Abstract]
Entity Registrant Name	FATE THERAPEUTICS, INC.
Entity Central Index Key	0001434316
Document Type	10-K
Document Period End Date	Dec. 31, 2023
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	false
Trading Symbol	FATE
Title of 12(b) Security	Common Stock, $0.001 par value
Security Exchange Name	NASDAQ
Document Annual Report	true
Document Transition Report	false
ICFR Auditor Attestation Flag	false
Document Financial Statement Error Correction Flag	false
Entity Public Float			$ 462,000,000
Entity Common Stock, Shares Outstanding		99,237,508
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Entity Tax Identification Number	65-1311552
Entity File Number	001-36076
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	12278 Scripps Summit Drive
Entity Address, City or Town	San Diego
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92131
City Area Code	858
Local Phone Number	875-1800
Documents Incorporated by Reference	Portions of the registrant’s definitive proxy statement to be filed with the Securities and Exchange Commission, or SEC, on or before the date 120 days after the conclusion of the registrant’s fiscal year ended December 31, 2023 pursuant to Regulation 14A, in connection with the registrant’s 2024 Annual Meeting of Stockholders are incorporated by reference into Part III of this annual report on Form 10-K.
Auditor Name	Ernst & Young, LLP
Auditor Location	San Diego, CA
Auditor Firm ID	42

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 41,870	$ 61,333
Accounts receivable	1,826	38,480
Short-term investments	273,305	374,894
Prepaid expenses and other current assets	14,539	27,367
Total current assets	331,540	502,074
Long-term investments	980	4,942
Property and equipment, net	96,836	110,020
Operating lease right-of-use assets	61,675	66,069
Restricted cash	15,177	15,227
Collaboration contract assets	0	7,196
Other assets	9	33
Total assets	506,217	705,561
Current liabilities:
Accounts payable	4,719	8,265
Accrued expenses	27,514	53,932
CIRM award liability	0	4,000
Deferred revenue	685	42,226
Operating lease liabilities, current portion	6,176	5,628
Total current liabilities	39,094	114,051
Operating lease liabilities, net of current portion	97,360	103,710
Stock price appreciation milestones, net of current portion	1,346	3,861
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.001 par value; authorized shares - 5,000,000 at December 31, 2023 and December 31, 2022; Class A Convertible Preferred shares issued and outstanding - 2,761,108 at December 31, 2023 and 2,794,549 December 31, 2022	3	3
Common stock, $0.001 par value; authorized shares - 250,000,000 at December 31, 2023 and December 31, 2022; issued and outstanding - 98,627,076 at December 31, 2023 and 97,294,917 at December 31, 2022	99	97
Additional paid-in capital	1,580,032	1,536,497
Accumulated other comprehensive loss	15	(1,854)
Accumulated deficit	(1,211,732)	(1,050,804)
Total stockholders’ equity	368,417	483,939
Total liabilities and stockholders’ equity	$ 506,217	$ 705,561

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, authorized shares	250,000,000	250,000,000
Common stock, issued shares	98,627,076	97,294,917
Common stock, outstanding shares	98,627,076	97,294,917
Class A Convertible Preferred Shares
Preferred stock, issued shares	2,761,108	2,794,549
Preferred stock, outstanding shares	2,761,108	2,794,549

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Statement [Abstract]
Collaboration revenue	$ 63,533	$ 96,300
Type of Revenue [Extensible List]	us-gaap:LicenseMember	us-gaap:LicenseMember
Operating expenses:
Research and development	$ 172,596	$ 320,454
General and administrative	81,448	84,232
Total operating expenses	254,044	404,686
Loss from operations	(190,511)	(308,386)
Other income (expense):
Interest income	17,186	5,842
Change in fair value of stock price appreciation milestones	2,515	20,307
Other income	9,882	516
Total other income (expense), net	29,583	26,665
Net loss	(160,928)	(281,721)
Other comprehensive (loss) gain:
Unrealized (loss) gain on available-for-sale securities, net	1,869	(1,092)
Comprehensive loss	$ (159,059)	$ (282,813)
Net loss per common share, Basic	$ (1.64)	$ (2.91)
Net loss per common share, Diluted	$ (1.64)	$ (2.91)
Weighted-average common shares used to compute basic net loss per share	98,411,162	96,826,058
Weighted-average common shares used to compute diluted net loss per share	98,411,162	96,826,058

Consolidated Statements of Conv

Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Gain (Loss)	Accumulated Deficit	Convertible Preferred Stock Preferred Stock [Member]
Balance at Dec. 31, 2021	$ 678,838	$ 96	$ 1,448,584	$ (762)	$ (769,083)	$ 3
Balance (in shares) at Dec. 31, 2021		95,726,962				2,794,549
Exercise of stock options, net of issuance costs	$ 9,181	$ 1	$ 9,180
Exercise of stock options, net of issuance costs (in shares)		941,780
Issuance of common stock upon vesting of restricted stock units (in shares)	0	626,175
Stock–based compensation	$ 78,733		$ 78,733
Unrealized loss on investments, net	(1,092)			(1,092)
Net Income (Loss)	(281,721)				(281,721)
Balance at Dec. 31, 2022	483,939	$ 97	1,536,497	(1,854)	(1,050,804)	$ 3
Balance (in shares) at Dec. 31, 2022		97,294,917				2,794,549
Exercise of stock options, net of issuance costs	76		76
Exercise of stock options, net of issuance costs (in shares)		93,787
Issuance of common stock upon vesting of restricted stock units	1	$ 1
Issuance of common stock upon vesting of restricted stock units (in shares)		1,071,167
Conversion of preferred shares to common stock	1	$ 1
Conversion of preferred shares to common stock (in shares)		167,205				(33,441)
Stock–based compensation	43,459		43,459
Unrealized loss on investments, net	1,869			1,869
Net Income (Loss)	(160,928)				(160,928)
Balance at Dec. 31, 2023	$ 368,417	$ 99	$ 1,580,032	$ 15	$ (1,211,732)	$ 3
Balance (in shares) at Dec. 31, 2023		98,627,076				2,761,108

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating activities:
Net loss	$ (160,928)	$ (281,721)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation and amortization	18,282	13,758
Stock-based compensation	43,459	78,733
Accretion and amortization of premiums and discounts on investments, net	(11,398)	(256)
Amortization of collaboration contract asset	7,196	2,676
Deferred revenue	(41,541)	(6,381)
Changes in fair value of stock price appreciation milestones	(2,515)	(20,307)
Grant income from CIRM award	(4,000)	0
Changes in assets and liabilities:
Accounts receivable	36,654	(29,804)
Prepaid expenses and other assets	12,876	(18,330)
Accounts payable and accrued expenses	(28,940)	14,252
Right-of-use assets and lease liabilities, net	(1,408)	(828)
Net cash used in operating activities	(132,263)	(248,208)
Investing activities
Purchases of property and equipment	(6,153)	(35,566)
Purchases of investments	(358,810)	(404,796)
Maturities of investments	477,628	607,113
Net cash provided by (used in) investing activities	112,665	166,751
Financing activities
Issuance of common stock from equity incentive plans, net of issuance costs	85	9,207
Net cash provided by financing activities	85	9,207
Net change in cash, cash equivalents and restricted cash	(19,513)	(72,250)
Cash, cash equivalents and restricted cash at beginning of the year	76,560	148,810
Cash, cash equivalents and restricted cash at end of the year	57,047	76,560
Supplemental schedule of noncash investing and financing activities
Purchases of property and equipment in accounts payable	0	1,055
Right-of-use assets obtained in exchange for lease obligations	$ 0	$ 682

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Pay vs Performance Disclosure
Net Income (Loss)	$ (160,928)	$ (281,721)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Dec. 31, 2023
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

Organization and Summary of Sig

Organization and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Summary of Significant Accounting Policies	1. Organization and Summary of Significant Accounting Policies Organization Fate Therapeutics, Inc. (the Company) was incorporated in the state of Delaware on April 27, 2007 and has its principal operations in San Diego, California. The Company is a clinical-stage biopharmaceutical company dedicated to bringing off-the-shelf, multiplexed-engineered, iPSC-derived cellular immunotherapies to patients for the treatment of cancer and autoimmune diseases. As of December 31, 2023, the Company has devoted substantially all of its efforts to product development, raising capital and building infrastructure and has not generated any revenues from any sales of its therapeutic products. To date, the Company’s revenues have been derived from collaboration agreements and government grants. Use of Estimates The Company’s consolidated financial statements are prepared in accordance with United States generally accepted accounting principles (U.S. GAAP). The preparation of the Company’s consolidated financial statements requires it to make estimates and assumptions that impact the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities in the Company’s consolidated financial statements and accompanying notes. The most significant estimates in the Company’s consolidated financial statements relate to its stock appreciation milestone obligations, contracts containing leases, and accrued expenses. Although these estimates are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions. Principles of Consolidation The consolidated financial statements include the accounts of the Company and its subsidiaries. To date, the aggregate operations of these subsidiaries have not been significant and all intercompany transactions and balances have been eliminated in consolidation. Segment Reporting Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business in one operating and reportable segment. Fair Value of Financial Instruments The Company’s financial instruments consist primarily of cash and cash equivalents, marketable securities, accounts receivable, stock price appreciation milestones, accounts payable, and accrued liabilities. The carrying amounts of accounts receivable, accounts payable and accrued liabilities are considered to be representative of their respective fair values because of the relatively short-term nature of those instruments. The accounting guidance defines fair value, establishes a consistent framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring or nonrecurring basis. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, the accounting guidance establishes a three- tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows: Level 1: Observable inputs such as quoted prices in active markets; Level 2: Inputs, other than the quoted prices in active markets, that are observable either directly or indirectly; and Level 3: Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. Assets and liabilities are classified based on the lowest level of input that is significant to the fair value measurements. The Company reviews the fair value hierarchy classification on a quarterly basis. Cash, Cash Equivalents and Restricted Cash Cash and cash equivalents include cash in readily available checking and savings accounts, money market accounts and money market funds. The Company considers all highly liquid investments with an original maturity of three months or less from the date of purchase to be cash equivalents. The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the consolidated balance sheets that sum to the total of the same such amounts shown in the consolidated statements of cash flows as of December 31, 2023 and 2022 (in thousands): Years Ended December 31, 2023 2022 Cash and cash equivalents $ 41,870 $ 61,333 Restricted cash 15,177 15,227 Total cash, cash equivalents, and restricted cash shown in the consolidated statement of cash flows $ 57,047 $ 76,560 For the years ended December 31, 2023 and 2022 , the restricted cash balance includes cash-collateralized irrevocable standby letters of credit for $ 15.2 million associated with the Company’s facilities leases . Investments Investments are accounted for as available-for-sale securities and are carried at fair value on the consolidated balance sheets. Upon initial recognition of the investment and at each reporting period, the Company evaluates whether any unrealized losses on investments are attributable to a credit loss or other factors. Any unrealized losses attributable to credit loss are recorded through an allowance for credit losses, limited to the amount by which the fair value is below amortized cost, with the offsetting amount recorded in other income or expense in the consolidated statement of operations and comprehensive loss. Unrealized losses not attributable to an expected credit loss and unrealized gains on investments are recorded in other comprehensive income (loss) on the consolidated statements of operations and comprehensive loss. Realized gains and losses, if any, on investments classified as available-for-sale securities are included in other income or expense. The amortized cost of investments classified as available-for-sale debt securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion are included in interest income. The cost of securities sold is based on the specific identification method. Interest and dividends on securities classified as available-for-sale are included in interest income. Concentration of Credit Risk Financial instruments, which potentially subject the Company to a significant concentration of credit risk, consist primarily of cash and cash equivalents and investments. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts and management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits and investments are held. Property and Equipment Property and equipment are recorded at cost and depreciated using the straight-line method over the estimated useful lives of the assets (generally two to five years ) and generally consist of furniture and fixtures, computers, scientific and office equipment, and in-process costs related to facilities construction. Repairs and maintenance costs are charged to expense as incurred. Impairment of Long-Lived Assets Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. An impairment loss is recorded if and when events and circumstances indicate that assets might be impaired and the undiscounted cash flows estimated to be generated by those assets are less than the carrying amount of those assets. If the carrying amount is not recoverable, the Company measures the amount of any impairment by comparing the carrying value of the asset to the present value of the expected future cash flows associated with the use of the asset. While the Company’s current and historical operating losses and negative cash flows are indicators of impairment, management believes that future cash flows to be received support the carrying value of its long-lived assets and, accordingly, has not recognized any impairment losses since the Company’ s inception. Leases The Company determines if a contract contains a lease at the inception of the contract. The Company currently has leases related to its facilities leased for office and laboratory space, which are classified as operating leases. These leases result in operating right-of-use (ROU) assets, current operating lease liabilities, and non-current operating lease liabilities in the Company’s consolidated balance sheets. The Company does not have any financing leases. Leases with a term of 12 months or less are considered short-term and ROU assets and lease obligations are not recognized. Payments associated with short-term leases are expensed on a straight-line basis over the lease term. Lease liabilities represent an obligation to make lease payments arising from the lease and ROU assets represent the right to use the underlying asset identified in the lease for the lease term. Lease liabilities are measured at the present value of the lease payments not yet paid discounted using the discount rate for the lease established at the lease commencement date. To determine the present value, the implicit rate is used when readily determinable. For those leases where the implicit rate is not provided, the Company determines an incremental borrowing rate based on the information available at the lease commencement date in determining the present value of lease payments. ROU assets are measured as the present value of the lease payments and also include any prepaid lease payments made and any other indirect costs incurred, and exclude any lease incentives received. Lease terms may include the impact of options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease expense for operating leases is recognized on a straight-line basis over the lease term. The Company aggregates all lease and non-lease components for each class of underlying assets into a single lease component. Collaborative Arrangements The Company analyzes its collaboration arrangements to assess whether they are within the scope of ASC Topic 808, Collaborative Arrangements (ASC 808), to determine whether such arrangements involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards that are dependent on the commercial success of such activities. To the extent the arrangement is within the scope of ASC 808, the Company assesses whether aspects of the arrangement between the Company and its collaboration partner are within the scope of other accounting literature, including ASC Topic 606, Revenue from Contracts with Customers (ASC 606). If it is concluded that some or all aspects of the arrangement represent a transaction with a customer, the Company will account for those aspects of the arrangement within the scope of ASC 606. ASC 808 provides guidance for the presentation and disclosure of transactions in collaborative arrangements, but it does not provide recognition or measurement guidance. Therefore, if the Company concludes a counterparty to a transaction is not a customer or otherwise not within the scope of ASC 606, the Company considers the guidance in other accounting literature as applicable or by analogy to account for such transaction. The classification of transactions under the Company’s arrangements is determined based on the nature and contractual terms of the arrangement along with the nature of the operations of the participants. Revenue Recognition The Company analyzes its collaboration arrangements to assess whether they are within the scope of ASC 808, to determine whether such arrangements involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards that are dependent on the commercial success of such activities. If the Company concludes that some or all aspects of the arrangement represent a transaction with a customer, the Company accounts for those aspects of the arrangement within the scope of ASC 606. For arrangements attributable to ASC 606, the Company recognizes revenue in a manner that depicts the transfer of control of a product or a service to a customer and reflects the amount of the consideration the Company is entitled to receive in exchange for such product or service. In doing so, the Company follows a five-step approach: (i) identify the contract with a customer, (ii) identify the performance obligations in the contract, (iii) determine the transaction price, (iv) allocate the transaction price to the performance obligations, and (v) recognize revenue when (or as) the customer obtains control of the product or service. Stock Price Appreciation Milestones The Company estimates the fair value of the stock price appreciation milestones associated with the Amended and Restated Exclusive License Agreement with Memorial Sloan Kettering Cancer Center (MSKCC) using a Monte Carlo simulation model, which relies on the Company’s current stock price as well as significant estimates and assumptions to determine the estimated liability associated with the contingent milestone payments. The Company accounts for the fair value of the stock price appreciation milestones in accordance with ASC 815, Derivatives and Hedging, with fair value marked to market at each reporting date. The assumptions used to calculate the fair value of the stock price appreciation milestones are subject to a significant amount of judgment including the probability of achieving a specified clinical milestone, the expected volatility of the Company’s common stock, the risk-free interest rate, and the estimated term, which is based in part on the last valid patent claim date. The Company remeasures the fair value of the stock price appreciation milestones at each balance sheet date, with changes in fair value recorded in earnings as non-operating income or expense on the consolidated statements of operations and comprehensive loss. Stock-Based Compensation Stock-based compensation expense represents the cost of the grant date fair value of employee stock option and restricted stock unit grants recognized over the requisite service period of the awards (usually the vesting period) on a straight-line basis. Performance-based stock units/awards represent a right to receive a certain number of shares of the Company’s common stock based on the achievement of corporate performance goals and continued employment during the vesting period. At each reporting period, and to the extent achievement of one or any of the performance conditions is probable, the Company reassesses the probability of the achievement of such corporate performance goals and any increase or decrease in share-based compensation expense resulting from an adjustment in the estimated shares to be released is treated as a cumulative catch-up in the period of adjustment. For stock awards for which vesting is subject to both performance-based milestones and market conditions, expense is recorded over the derived service period after the point when the achievement of the performance-based milestone is probable or the performance condition has been achieved. The Company estimates the fair value of stock option grants using the Black-Scholes option pricing model, with the exception of option grants for which vesting is subject to both performance-based milestones and market conditions, which are valued using a lattice-based model. The fair value of restricted stock units, including performance-based restricted stock units, is based on the closing price of the Company’s common stock as reported on The Nasdaq Global Market on the date of grant. The Company recognizes forfeitures for all awards as such forfeitures occur. Income Taxes The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. The Company recognizes net deferred tax assets to the extent that the Company believes these assets are more likely than not to be realized. In making such a determination, management considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If management determines that the Company would be able to realize its deferred tax assets in the future in excess of their net recorded amount, management would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. The Company records uncertain tax positions on the basis of a two-step process whereby (1) management determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more- likely-than-not recognition threshold, management recognizes the largest amount of tax benefit that is more than 50 percent likely to be realized upon ultimate settlement with the related tax authority. The Company recognizes interest and penalties related to unrecognized tax benefits within income tax expense. Any accrued interest and penalties are included within the related tax liability. Employee Retention Credit The CARES Act provides an employee retention credit (ERC), which is a refundable tax credit against certain employment taxes of up to $ 5,000 per employee for eligible employers. The tax credit is equal to 50 % of qualified wages paid to employees during a quarter, capped at $ 10,000 of qualified wages per employee through December 31, 2020. Additional relief provisions were passed by the United States government, which extend and slightly expand the qualified wage caps on these credits through December 31, 2021. Based on these additional provisions, the tax credit is now equal to 70 % of qualified wages paid to employees during a quarter, and the limit on qualified wages per employee has been increased to $ 10,000 of qualified wages per quarter. The Company qualifies for the tax credit under the CARES Act and expects to continue to receive additional tax credits under the additional relief provisions for qualified wages through December 31, 2021. In connection with the CARES Act, the Company adopted a policy to recognize the employee retention credit when received and include in other income in the statement of operations. T he Company received a cash payment and recorded $ 5.1 million and $ 0.5 million of other income during the years ended December 31, 2023 and 2022, respectively . Comprehensive Loss Comprehensive loss is defined as a change in equity during a period from transactions and other events and circumstances from non‑owner sources. Other comprehensive loss includes unrealized gains and losses on available-for-sale securities. Net Loss Per Common Share Basic net loss per common share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period, without consideration for common stock equivalents. The Pre-Funded Warrants associated with the January 2021 public equity offering (see Note 9) are considered outstanding shares in the basic earnings per share calculation given their nominal exercise price. Dilutive common stock equivalents comprise convertible preferred stock, warrants for the purchase of common stock, and common stock options and restricted stock units outstanding under the Company’s stock option plans. For all periods presented, there is no difference in the number of common shares used to calculate basic and diluted common shares outstanding due to the Company’s net loss position. Potentially dilutive securities that are not included in the calculation of diluted net loss per common share because to do so would be anti-dilutive are as follows (in common stock equivalent shares): As of December 31, 2023 2022 Common stock options 9,850,841 7,267,226 Restricted stock units 3,065,087 5,862,733 Series A convertible preferred stock (if converted) 13,805,540 13,972,745 Total 26,721,468 27,102,704 Going Concern Assessment Substantial doubt about an entity’s ability to continue as a going concern exists when relevant conditions and events, considered in the aggregate, indicate that it is probable that the entity will be unable to meet its obligations as they become due within one year from the financial statement issuance date. The Company determined that there are no conditions or events that raise substantial doubt about its ability to continue as a going concern for a period of at least twelve months from the date of issuance of these financial statements . Restructuring In January 2023, the Company implemented a corporate restructuring to streamline operations, reduce operating expenses, extend cash runway and focus resources on the Company’s most promising programs. In connection with the restructuring, the Company reduced its workforce by 60 %. Affected employees were informed on January 5, 2023. The restructuring was completed by March 31, 2023. The Company incurred charges of $ 12.9 million during the year ended December 31, 2023 for severance and other employee termination-related costs, of which $ 10.9 million were related to research and development expenses and $ 2.0 million were related to general and administrative expenses. All restructuring and related expenses have been fully recognized by the Company.

Collaboration and License Agree

Collaboration and License Agreements	12 Months Ended
	Dec. 31, 2023
Collaboration And License Agreements Disclosure [Abstract]
Collaboration and License Agreements	2. Collaboration and License Agreements Ono Collaboration and Option Agreement On September 14, 2018, the Company entered into a Collaboration and Option Agreement (the Ono Agreement) with Ono Pharmaceutical Co., Ltd. (Ono) for the joint development and commercialization of two off-the-shelf iPSC-derived CAR T-cell product candidates (Candidate 1 and Candidate 2). Pursuant to the terms of the Ono Agreement, the Company received an upfront, non-refundable and non-creditable payment of $ 10.0 million. Additionally, the Company is entitled to receive funding for the conduct of research and development under a joint development plan, which fees were estimated to be $ 20.0 million in aggregate. In December 2020, the Company entered into a letter agreement with Ono pursuant to which Ono delivered proprietary antigen binding domains targeting an antigen expressed on certain solid tumors for incorporation into Candidate 2 and paid the Company a milestone fee of $ 10.0 million for further research and development of Candidate 2. In addition, Ono terminated all further research and development with respect to Candidate 1, and the Company retained all rights to research, develop and commercialize Candidate 1 throughout the world without any obligation to Ono. In June 2022, the Company entered into an amendment with Ono to the Ono Agreement (the 2022 Ono Amendment). Pursuant to the 2022 Ono Amendment, the companies agreed to designate an additional antigen expressed on certain solid tumors for research and preclinical development, and Ono agreed to contribute proprietary antigen binding domains targeting such additional solid tumor antigen (Candidate 3). In addition, for both Candidate 2 and Candidate 3, Ono and the Company expanded the scope of the collaboration to include the research and development of iPSC-derived CAR NK cell product candidates (in addition to iPSC-derived CAR T-cell product candidates) targeting the designated solid tumor antigens. Similar to Candidate 2, the Company granted to Ono, during a specified period of time, a preclinical option to obtain an exclusive license under certain intellectual property rights, subject to payment of an option exercise fee to the Company by Ono, to develop and commercialize Candidate 3 in all territories of the world, where the Company retains rights to co-develop and co-commercialize Candidate 3 in the United States and Europe under a joint arrangement with Ono under which the Company is eligible to share at least 50 % of the profits and losses. The Company will continue to receive committed funding from Ono through September 2024 and has maintained worldwide rights of manufacture for Candidate 3. The preclinical option expires upon the earlier of: (a) September 30, 2024 or (b) the achievement of the pre-defined preclinical milestone under the joint development plan for Candidate 3. Subject to payment of an extension fee by Ono, Ono may choose to defer its decision to exercise the preclinical option until no later than June 2026. Under the 2022 Ono Amendment, aggregate estimated research and development fees have been increased by approximately $ 9.3 million, for a total estimated $ 29.3 million in aggregate research and development fees over the course of the joint development plan. On November 7, 2022, Ono exercised its option for continued development of Candidate 2. Upon Ono’ s exercise, the Company granted Ono a license to develop and commercialize Candidate 2. The Company elected its preclinical option to co-develop and co-commercialize Candidate 2. As a result, the Company received an Option Exercise Payment (as defined under the Ono Agreement) of $ 12.5 million. The Company determined the exercise represented an option with no material right under the Ono Agreement. The Company has completed its performance obligations with respect to the exercise of the option and accordingly, recognized the Option Exercise Payment as revenue for the year ended December 31, 2022. The Company and Ono will proceed with a joint development plan for the ongoing development of Candidate 2. The costs of this development plan are accounted for in accordance with ASC 808, and cost sharing payments to the Company from Ono are recorded net into r esearch and development expenses. During the year ended December 31, 2023 , the Company recognized contra-research and development expense of $ 8.0 million. There were no such amounts recognized during the year ended December 31, 2022 As of December 31, 2023 , the Company has received $ 6.2 million in aggregate cost-sharing payments from Ono. On November 30, 2023, the Company entered into an amendment with Ono to the Ono Agreement (the 2023 Ono Amendment). Under the 2023 Ono Amendment, aggregate estimated research and development fees have been increased by approximately $ 1.4 million, for a total estimated $ 30.7 million in aggregate research and development fees over the course of the joint development plan. Under the terms of the Ono Agreement (as amended by the 2022 Ono Amendment), for Candidate 2 and for Candidate 3 (subject to exercise by Ono of its preclinical option to Candidate 3), the Company is eligible to receive additional payments upon the achievement of certain clinical, regulatory and commercial milestones (the Ono Milestones) with respect to each Candidate in an amount up to $ 843.0 million in aggregate, with the applicable milestone payments for the United States and Europe subject to reduction by 50 % if the Company elects to co-develop and co-commercialize the Candidate in the United States and Europe as described above. In addition, in those territories where Ono has exclusive rights of commercialization, the Company is eligible to receive tiered royalties (Royalties) ranging from the mid-single digits to the low-double digits based on annual net sales by Ono for each Candidate in such territories, with the Royalties subject to certain reductions. The Ono Agreement will terminate with respect to a Candidate if Ono does not exercise its option for a candidate within the option period, or in its entirety if Ono does not exercise any of its options for the candidates within their respective option periods. In addition, either party may terminate the Ono Agreement in the event of breach, insolvency or patent challenges by the other party; provided, that Ono may terminate the Ono Agreement in its sole discretion (x) on a Candidate-by-Candidate basis at any time after the second anniversary of the effective date of the Ono Agreement or (y) on a Candidate-by-Candidate or country-by-country basis at any time after the expiration of the option period, subject to certain limitations. The Ono Agreement will expire on a Candidate-by-Candidate and country-by-country basis upon the expiration of the applicable Royalty term, or in its entirety upon the expiration of all applicable payment obligations under the agreement. The Company determined that the Ono Agreement, Ono Letter Agreement, and Ono Amendments were within the scope of ASC 808 and applicable to such guidance. The Company concluded that certain units of account within the Ono Agreement and Ono Amendments represented a customer and applied relevant guidance from ASC 606 to evaluate the appropriate accounting for those units of account. In accordance with this guidance, the Company identified its performance obligations, including its grant of a license to Ono to certain of its intellectual property subject to certain conditions, its conduct of research services, and its participation in a joint steering committee. The Company determined that its grant of a license to Ono to certain of its intellectual property subject to certain conditions was not distinct from other performance obligations because such grant is dependent on the conduct and results of the research services. Additionally, the Company determined that its conduct of research services was not distinct from other performance obligations since such conduct is dependent on the guidance of the joint steering committee. Accordingly, the Company determined that all performance obligations should be accounted for as one combined performance obligation, and that the combined performance obligation is transferred over the expected term of the conduct of the research services. The termination of the Ono Agreement with respect to Candidate 1 did not impact this assessment. In accordance with ASC 606, the Company determined that the initial transaction price under the 2023 Ono Amendment equaled $ 40.7 million, consisting of the upfront, non-refundable and non-creditable payment of $ 10.0 million and the aggregate estimated research and development fees of $ 30.7 million. The upfront payment of $ 10.0 million was recorded as deferred revenue and was recognized as revenue over time in conjunction with the Company’s conduct of research services as the research services are the primary component of the combined performance obligations. Revenue associated with the upfront payment was recognized based on actual costs incurred as a percentage of the estimated total costs expected to be incurred over the expected term of conduct of the research services. The Company recorded the $ 5.0 million prepayment of the first-year research and development fees as deferred revenue, and such fees were recognized as revenue as the research services were delivered. As a direct result of the Company’s entry into the Ono Agreement and the Ono Letter Agreement, the Company incurred an aggregate of $ 7.8 million in sublicense consideration to existing licensors of the Company. The $ 7.8 million in sublicense consideration represents an asset under ASC 340 and is being amortized to research and development expense ratably with the Company’s revenue recognition under the Ono Agreement. During the years ended December 31, 2022, the Company recognized $ 4.1 million of such expense. During the year ended December 31, 2023, the Company recognized no such expense. The Company recognized revenue of $ 11.2 million and $ 16.6 million under the Ono Agreement and Ono Letter Agreement during the years ended December 31, 2023 and 2022, respectively. Such revenue comprised $ 11.2 million associated with research services during the year ended December 31, 2023. Suc h revenue comprised $ 2.5 million associated with research services and $ 1.6 million associated with the upfront payment, and $ 12.5 million associated with the option exercise during the year ended December 31, 2022. As of December 31, 2023, aggregate deferred revenue related to the Ono Agreement and Ono Letter Agreement was $ 0.7 million, all of which is classified as current. As of December 31, 2023, the Company has received $ 32.7 million in cash of aggregate research and development fees from Ono. Janssen Collaboration and Option Agreement On April 2, 2020 (the Janssen Agreement Effective Date), the Company entered into a Collaboration and Option Agreement (the Janssen Agreement) with Janssen Biotech, Inc. (Janssen), part of the Janssen Pharmaceutical Companies of Johnson & Johnson. Additionally, on the Janssen Agreement Effective Date, the Company entered into a Stock Purchase Agreement (the Stock Purchase Agreement) with Johnson & Johnson Innovation - JJDC, Inc. (JJDC). On January 3, 2023, the Company received notice of termination from Janssen of the Janssen Agreement. The termination took effect on April 3, 2023, and during the three months ended March 31, 2023, the Company performed wind-down activities including discontinuing development of all collaboration product candidates under the Janssen Agreement. The Company was reimbursed for all wind-down activities. Under the terms of the Janssen Agreement and the Stock Purchase Agreement taken together, the Company received $ 100.0 million, of which $ 50.0 million was an upfront cash payment and $ 50.0 million was in the form of an equity investment by JJDC. The Company determined the common stock purchase by JJDC represented a premium of $ 9.93 per share, or $ 16.0 million in aggregate (the Equity Premium), and the remaining $ 34.0 million was recorded as issuance of common stock in shareholders’ equity. In addition, under the Stock Purchase Agreement, the Company exercised the right to require JJDC to purchase an aggregate of $ 50.0 million in shares in a private placement at the same price per share as paid by investors in a public offering. In June 2020, JJDC purchased 1.8 million shares of the Company’s common stock at a price of $ 28.31 per share. Additionally, the Company received full funding for the conduct of all research, preclinical development and Investigational New Drug Application (IND)-enabling activities performed by the Company under the Janssen Agreement. As a direct result of the Company’s entry into the Janssen Agreement, the Company incurred $ 17.1 million in sublicense fees to certain of its existing licensors. The $ 17.1 million in sublicense consideration represents an asset under ASC 340, Other Assets and Deferred Costs (ASC 340) and is amortized to research and development expense ratably with the Company’s revenue recognition under the Janssen Agreement. During the years ended December 31, 2023 and 2022 , the Company recognized $ 7.2 million and $ 4.3 million of such expense, respectively. As of December 31, 2023, there was no remaining balance on the Janssen Agreement contract asset. The Company recognized revenue of $ 52.3 million under the Janssen Agreement for the year ended December 31, 2023 , of which $ 41.2 million was previously deferred. Such revenue comprised $ 11.1 million associated with research and development services, $ 31.2 m illion associated with the upfront fee and Equity Premium, and $ 10.0 million associated with a commercial option exercise for the year ended December 31, 2023 . The Company recognized revenue of $ 79.7 million under the Janssen Agreement for the year ended December 31, 2022 . Such revenue comprised $ 42.3 million associated with research and development services and $ 23.1 million associated with the upfront fee and Equity Premium, $ 13.0 million associated with a commercial option exercise and milestone achievements, and $ 1.3 million associated with collaboration services for the year ended December 31, 2022. Memorial Sloan Kettering Cancer Center License Agreement On May 15, 2018, the Company entered into an Amended and Restated Exclusive License Agreement (the Amended MSKCC License) with MSKCC. The Amended MSKCC License amends and restates the Exclusive License Agreement entered into between the Company and MSKCC on August 19, 2016 (the Original MSKCC License), pursuant to which the Company entered into an exclusive license agreement with MSKCC for rights relating to compositions and methods covering iPSC-derived cellular immunotherapy, including T-cells and NK-cells derived from iPSCs engineered with CARs. Pursuant to the Amended MSKCC License, MSKCC granted to the Company additional licenses to certain patents and patent applications relating to new CAR constructs and off-the-shelf CAR T-cells, including the use of clustered regularly interspaced short palindromic repeat (CRISPR) and other innovative technologies for their production, in each case to research, develop, and commercialize licensed products in the field of all human therapeutic uses worldwide. The Company has the right to grant sublicenses to certain licensed rights in accordance with the terms of the Amended MSKCC License, in which case it is obligated to pay MSKCC a percentage of certain sublicense income received by the Company. The Company is obligated to pay to MSKCC an annual license maintenance fee during the term of the agreement, and milestone payments upon the achievement of specified clinical, regulatory and commercial milestones for licensed products as well as royalty payments on net sales of licensed products. In the event a licensed product achieves a specified clinical milestone, MSKCC is then eligible to receive certain milestone payments totaling up to $ 75.0 million based on the price of the Company’s common stock, where the amount of such payments owed to MSKCC is contingent upon certain increases in the price of the Company’s common stock following the date of achievement of such clinical milestone. These payments are based on common stock price multiples, with the numerator being the fair value of the ten-trading day trailing average closing price of the Company’s common stock and the denominator being the ten-trading day trailing average closing price of the Company’s common stock as of the effective date of the Amended MSKCC License, adjusted for any stock splits, cash dividends, stock dividends, other distributions, combinations, recapitalizations, or similar events. Under the terms of the Amended MSKCC License, upon a change of control of the Company, in certain circumstances, the Company may be required to pay a portion of these payments to MSKCC based on the price of the Company’s common stock in connection with such change of control. The following table summarizes the common stock multiples and the stock price appreciation milestone payments under the terms of the agreement: Common stock multiple 5.0x 10.0x 15.0x Ten-trading day trailing average common stock price $ 50.18 $ 100.36 $ 150.54 Stock price appreciation milestone payment (in millions) $ 20.0 $ 30.0 $ 25.0 In July 2021, the Company achieved the specified clinical milestone for a licensed product under the Amended MSKCC License and the Company’s ten-trading day trailing average common stock price exceeded the first, pre-specified threshold. As a result, the Company remitted the first milestone payment of $ 20.0 million to MSKCC during the year ended December 31, 2021. To determine the estimated fair value of the remaining stock price appreciation milestones, the Company uses a Monte Carlo simulation methodology which models future Company common stock prices based on the current stock price and several key variables. The following variables were incorporated in the calculation of the estimated fair value of the stock price appreciation milestones as of December 31, 2023: Year Ended Year Ended 2023 2022 Risk-free interest rate 4.0 % 4.0 % Expected volatility 84.0 % 78.1 % Estimated term (in years) 15.0 16.0 Closing stock price as of measurement date $ 3.74 $ 10.09 The key inputs to the Monte Carlo simulation to determine the fair value of the stock price appreciation milestones include the Company’s stock price as of the measurement date; the estimated term which is based in part on the last valid patent claim date; the expected volatility of the Company’s common stock, estimated using the Company’s historical common stock volatility as of the remeasurement date; and the risk-free rate based on the U.S. Treasury yield for the estimated term determined. Fair value measurements are highly sensitive to changes in these inputs and significant changes could result in a significantly higher or lower fair value and resulting expense or gain. At each balance sheet date, the Company remeasures the fair value of the stock price appreciation milestones, with changes in fair value recognized as a component of other income (expense) in the consolidated statements of operations and comprehensive loss. Amounts are included in current or non-current liabilities based on the estimated timeline associated with the individual potential payments. During the years ended December 31, 2023 and 2022, the Company recorded $ 2.5 million and $ 20.3 million of income, respectively, associated with the change in fair value of the stock price appreciation milestones. As of December 31, 2023 and 2022, the Company recorded a liability of $ 1.3 million and $ 3.9 million, respectively, associated with the stock price appreciation milestones for the Amended MSKCC License.

California Institute for Regene

California Institute for Regenerative Medicine Award	12 Months Ended
	Dec. 31, 2023
Award From California Institute For Regenerative Medicine Abstract
California Institute for Regenerative Medicine Award	3. California Institute for Regenerative Medicine Award On April 5, 2018 , the Company executed an award agreement with the California Institute for Regenerative Medicine (CIRM) pursuant to which CIRM awarded the Company $ 4.0 million to advance the Company’s FT516 product candidate into a first-in-human clinical trial for the treatment of subjects with advanced solid tumors, including in combination with monoclonal antibody therapy (the Award). The Award is subject to certain co-funding requirements by the Company, and the Company is required to provide CIRM progress and financial update reports under the Award. Pursuant to the terms of the Award, the Company, in its sole discretion, has the option to treat the Award either as a loan or as a grant. During the first quarter of 2023, the Company elected to treat the Award as a grant and derecognized the liability associated with the Award and recorded such amount in other income during the year ended December 31, 2023.

Investments

Investments	12 Months Ended
	Dec. 31, 2023
Investments [Abstract]
Investments	4. Investments The Company invests portions of excess cash in United States treasuries, commercial paper, non-U.S. government securities, municipal securities, and corporate debt securities with maturities ranging from three to thirty-six months from the purchase date. These investments are accounted for as available-for-sale securities and are classified as short-term and long-term investments in the accompanying consolidated balance sheets based on each security’s contractual maturity date. The following table summarizes the Company’s investments accounted for as available-for-sale securities as of December 31, 2023 and 2022 (in thousands): Maturity Amortized Unrealized Unrealized Estimated December 31, 2023 Classified as current assets: Money market fund 1 or less $ 35,273 $ — $ — $ 35,273 U.S. Treasury debt securities 1 or less 82,811 ( 34 ) 27 82,804 Non-US government securities 1 or less 999 — — 999 Municipal securities 1 or less 5,000 ( 3 ) — 4,997 Corporate debt securities 1 or less 47,144 ( 51 ) 14 47,107 Commercial paper 1 or less 137,339 ( 62 ) 121 137,398 Total short-term investments $ 308,566 $ ( 150 ) $ 162 $ 308,578 Classified as non-current assets: Corporate debt securities Greater than 1 $ 977 $ — $ 3 $ 980 Total long-term investments $ 977 $ — $ 3 $ 980 December 31, 2022 Classified as current assets: Money market fund 1 or less $ 37,645 $ — $ — $ 37,645 U.S. Treasury debt securities 1 or less 86,221 ( 263 ) 37 85,995 Non-US government securities 1 or less 2,425 ( 2 ) — 2,423 Municipal securities 1 or less 18,963 ( 208 ) — 18,755 Corporate debt securities 1 or less 126,691 ( 1,138 ) 5 125,558 Commercial paper 1 or less 152,056 ( 230 ) 4 151,830 Total short-term investments $ 424,001 $ ( 1,841 ) $ 46 $ 422,206 Classified as non-current assets: Municipal securities Greater than 1 $ 5,000 $ ( 58 ) $ — $ 4,942 Total long-term investments $ 5,000 $ ( 58 ) $ — $ 4,942 As of December 31, 2023 and 2022, the Company had $ 0.9 million and $ 0.8 million, respectively, of accrued interest on investments recorded in prepaid expenses and other assets on the consolidated balance sheets. The Company reviews its investment holdings at the end of each reporting period and evaluates any unrealized losses using the expected credit loss model to determine if the unrealized loss is a result of a credit loss or other factors. The Company also evaluates its investment holdings for impairment using a variety of factors including the Company’s intent to sell the underlying securities prior to maturity and whether it is more likely than not that the Company would be required to sell the securities before the recovery of their amortized basis. During the years ended December 31, 2023 and 2022 , the Company did no t recognize any impairment or realized gains or losses on sales of investments, and the Company did not record an allowance for, or recognize, any expected credit losses.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurements	5. Fair Value Measurements The following tables presents the Company’s financial assets and liabilities measured at fair value on a recurring basis as of December 31, 2023 and 2022 (in thousands): Fair Value Measurements at Total Quoted Prices Significant Significant As of December 31, 2023: Financial assets: Money market fund $ 35,273 $ 35,273 $ — $ — U.S. Treasury debt securities 82,804 82,804 — — Non-US government securities 999 — 999 — Municipal securities 4,997 — 4,997 — Corporate debt securities 48,087 — 48,087 — Commercial paper 137,398 — 137,398 — Total assets measured at fair value on a recurring basis $ 309,558 $ 118,077 $ 191,481 $ — Financial liabilities: Stock price appreciation milestones $ 1,346 $ — $ — $ 1,346 Total financial liabilities measured at fair value on a recurring basis $ 1,346 $ — $ — $ 1,346 As of December 31, 2022: Financial assets: Money market fund $ 37,645 $ 37,645 $ — $ — U.S. Treasury debt securities 85,995 85,995 — — Non-US government securities 2,423 — 2,423 — Municipal securities 23,697 — 23,697 — Corporate debt securities 125,558 — 125,558 — Commercial paper 151,830 — 151,830 — Total assets measured at fair value on a recurring basis $ 427,148 $ 123,640 $ 303,508 $ — Financial liabilities: Stock price appreciation milestones $ 3,861 $ — $ — $ 3,861 Total financial liabilities measured at fair value on a recurring basis $ 3,861 $ — $ — $ 3,861 Level 1 assets consisted of money market funds and U.S. Treasury securities measured at fair value based on quoted prices in active markets as provided by the Company’s investment managers. Level 2 assets consisted of corporate debt securities, commercial paper, municipal securities, and non-U.S. government securities measured at fair value using standard observable inputs, including reported trades, broker/dealer quotes, and bids and/or offers. The Company validates the quoted market prices provided by its investment managers by comparing the investment managers’ assessment of the fair values of the Company’s investment portfolio balance against the fair values of the Company’s investment portfolio balance obtained from an independent source. There were no Level 3 assets held by the Company as of December 31, 2023. Level 3 liabilities consisted of stock price appreciation milestones associated with the Amended MSKCC License as described in detail in Note 2. The following table presents the changes in fair value of the Company’s Level 3 stock price appreciation milestones liability (in thousands): Balance at December 31, 2021 $ 24,168 Changes in fair value of stock price appreciation milestones liability ( 20,307 ) Balance at December 31, 2022 $ 3,861 Changes in fair value of stock price appreciation milestones liability ( 2,515 ) Balance at December 31, 2023 $ 1,346 None of the Company’s non-financial assets or liabilities are recorded at fair value on a non-recurring basis. No transfers between levels have occurred during the periods presented.

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Property and Equipment	6. Property and Equipment Property and equipment consist of the following (in thousands): December 31, 2023 2022 Furniture and fixtures $ 1,309 $ 1,209 Computer and office equipment 3,132 2,937 Software 2,130 2,122 Leasehold improvements—building 59,038 56,782 Scientific equipment 78,853 77,354 Total property and equipment, gross 144,462 140,404 Less accumulated depreciation and amortization ( 47,626 ) ( 30,384 ) Total property and equipment, net $ 96,836 $ 110,020 Depreciation expense related to property and equipment was $ 18.3 million and $ 13.8 million, for the years ended December 31, 2023 and 2022 , respectively.

Accrued Expenses and Long-Term

Accrued Expenses and Long-Term Debt	12 Months Ended
	Dec. 31, 2023
Accrued Expenses And Long Term Debt Disclosure [Abstract]
Accrued Expenses and Long-Term Debt	7. Accrued Expenses Accrued Expenses Current accrued expenses consist of the following (in thousands): December 31, 2023 2022 Accrued payroll and other employee benefits $ 10,563 $ 17,899 Accrued clinical trial related costs 8,833 16,858 Accrued other 8,118 19,175 Total current accrued expenses $ 27,514 $ 53,932

Leases

Leases	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Leases	8. Leases The Company has lease agreements for office, laboratory and manufacturing spaces that are classified as operating leases on the consolidated balance sheets. These leases have terms varying from one to approximately sixteen years, with renewal options of up to ten years , as well as early termination options. Extension and termination options are included in the total lease term when the Company is reasonably certain to exercise them. The leases are subject to additional variable charges, including common area maintenance, property taxes, property insurance and other variable costs. Given the variable nature of such costs, they are recognized as expense as incurred. Additionally, some of the Company’s leases are subject to certain fixed fees which the Company has determined to be non-lease components. The Company has elected to combine and account for lease and non-lease components as a single-lease component for purposes of determining the total future lease payments. As of December 31, 2023, future undiscounted minimum contractual payments under the Company’s operating leases were $ 162.9 million, which will be paid over a remaining weighted-average lease term of 10.7 years. The weighted-average discount rate for the operating lease liabilities was 8.34 %, which was the Company ’s incremental borrowing rate at lease commencement, as the discount rates implicit in the leases could not be readily determined. The components of lease expense for the years ended December 31, 2023 and 2022 were as follows (in thousands): Years Ended 2023 2022 Straight-line lease expense $ 13,159 $ 15,010 Variable lease expense 2,250 2,614 Total operating lease expense $ 15,409 $ 17,624 Future undiscounted minimum payments under the Company’s operating leases as of December 31, 2023 are as follows (in thousands): Operating Years Ending December 31, 2024 $ 14,659 2025 15,087 2026 15,540 2027 16,006 2028 15,057 Thereafter 86,579 Total undiscounted lease payments $ 162,928 Less: imputed interest ( 59,392 ) Total lease liability $ 103,536 In April 2023, the Company entered into an agreement to sublease approximately 18,913 square feet of space, which sublease agreement commenced in April 2023 and expires in December 2028 with no option to extend the sublease term. Under the sublease agreement, rent is subject to scheduled annual increases and the subtenant is responsible for certain operating expenses and taxes throughout the term of the sublease. Sublease income is recognized in other income. Sublease income for the years ended December 31, 2023 and 2022 was as follows (in thousands): Years Ended 2023 2022 Sublease income $ 729 $ —

Convertible Preferred Stock and

Convertible Preferred Stock and Stockholders' Equity	12 Months Ended
	Dec. 31, 2023
Convertible Preferred Stock And Stockholders Deficit Disclosure [Abstract]
Convertible Preferred Stock and Stockholders’ Equity	9. Convertible Preferred Stock and Stockholders’ Equity Convertible Preferred Stock In November 2016, the Company completed a private placement of stock in which investors, including investors affiliated with the directors and officers of the Company, purchased convertible preferred stock and common stock of the Company (the November 2016 Placement). The Company issued 2,819,549 shares of Class A Convertible Preferred Stock, $ 0.001 par value per share (the Class A Preferred), at $ 13.30 per share, each of which is convertible into five shares of common stock upon certain conditions defined in the Certificate of Designation of Preferences, Rights and Limitations of the Class A Preferred filed with the Delaware Secretary of State on November 22, 2016 (the CoD). The Class A Preferred were purchased exclusively by entities affiliated with Redmile Group, LLC (collectively, Redmile). The terms of the CoD prohibited Redmile from converting the Class A Preferred into shares of the Company’s common stock if, as a result of conversion, Redmile, together with its affiliates, would own more than 9.99 % of the Company’s common stock then issued and outstanding (the Redmile Percentage Limitation), which percentage could change at Redmile’s election upon 61 days’ notice to the Company to (i) any other number less than or equal to 19.99 % or (ii) subject to approval of the Company’s stockholders to the extent required in accordance with the NASDAQ Global Market rules, any number in excess of 19.99 %. On May 2, 2017, the Company’s stockholders approved the issuance of up to an aggregate of 14,097,745 shares of common stock upon the conversion of the outstanding shares of Class A Preferred. As a result, Redmile has the right to increase the Redmile Percentage Limitation to any percentage in excess of 19.99 % at its election. The Company also issued 7,236,837 shares of common stock at $ 2.66 per share as part of the November 2016 Placement. In April 2023, the Company filed with the office of the Secretary of State of the State of Delaware a Certificate of Amendment to Certificate of Designation of Preferences, Rights and Limitations of Class A Convertible Preferred Stock which amends the definition of Beneficial Ownership Limitation to be 14.99 % of the number of shares of the Company ’s common stock outstanding immediately after giving effect to the issuance of shares of common stock pursuant to a Notice of Conversion. In April 2023, 33,441 shares of the Company’s Class A Preferred were converted into 167,205 shares of the Company’s common stock. The Class A Preferred are non-voting shares and are convertible into five shares of the Company’s common stock at a conversion price of $ 2.66 per share, which was the fair value of the Company’s common stock on the date of issuance. Holders of the Class A Preferred have the same dividend rights as holders of the Company’s common stock. Additionally, the liquidation preferences of the Class A Preferred are pari passu among holders of the Company’s common stock and holders of the Class A Preferred, pro rata based on the number of shares held by each such holder (treated for this purpose as if the Class A Preferred had been converted to common stock). Stock Option and Incentive Plans and Inducement Equity Plan 2022 Stock Option and Incentive Plan On June 9, 2022, the Company adopted the 2022 Stock Option and Incentive Plan (the 2022 Plan). The 2022 Plan authorizes 9.5 million shares of common stock for issuance and allows for the grant of stock options, stock appreciation rights, restricted stock awards, performance-based awards, and other awards to individuals who are then employees, officers, directors or consultants of the Company. The shares of common stock underlying any awards from the 2022 Plan and a previously existing equity plan from 2013 or 2007 that are forfeited, cancelled, held back upon exercise or settlement of an award to satisfy the exercise price or tax withholding, reacquired by us prior to vesting, satisfied without any issuance of common stock, expire or are otherwise terminated (other than by exercise) are added back to the shares of common stock available for issuance under the 2022 Plan. Recipients of stock options under the 2022 Plan shall be eligible to purchase shares of the Company’s common stock at an exercise price equal to no less than the estimated fair value of such stock on the date of grant. Under the 2022 Plan, stock options generally vest 25 % on the first anniversary of the original vesting date, with the balance vesting monthly over the remaining three years , or vest monthly over four years , unless they contain specific performance and/or market-based vesting provisions. The maximum term of stock options granted under the 2022 Plan is ten years . Under the 2022 Plan, restricted stock units generally vest annually over four years . Performance-based stock units/awards vest upon the achievement of certain pre-defined company-specific performance-based clinical achievement criteria. Inducement Plan On May 10, 2016, the Company’s board of directors approved the Fate Therapeutics, Inc. Inducement Equity Plan (the Inducement Plan), the purpose of which is to enable the Company to grant equity awards to induce highly-qualified prospective officers and employees who are not employed by the Company to accept employment with the Company. Under the Inducement Plan, the Company may grant non-qualified stock options and restricted stock units. A total of 500,000 shares of common stock were initially reserved for issuance under the Inducement Plan. In January 2021, March 2020, and January 2019, an additional 300,000 shares, 470,822 shares, and 200,000 shares, respectively, of common stock were reserved for issuance under the Inducement Plan. The shares of common stock underlying any awards from the Inducement Plan that are forfeited, cancelled, held back upon exercise or settlement of an award to satisfy the exercise price or tax withholding, reacquired by us prior to vesting, satisfied without any issuance of common stock, expire or are otherwise terminated (other than by exercise) under the Inducement Plan will be added back to the shares of common stock available for issuance under the Inducement Plan. Pre-Funded Warrants In January 2021, in conjunction with a public offering, the Company issued Pre-Funded Warrants, in lieu of common stock to certain investors, to purchase 257,310 shares of the Company’s common stock. The purchase price for the Pre-Funded Warrants was $ 85.499 per Pre-Funded Warrant, which equals the per share public offering price for the shares of common stock less the $ 0.001 exercise price for each such Pre-Funded Warrant. Given that the Pre-Funded Warrants are indexed to the Company’s own shares of common stock (and otherwise meet the requirements to be classified in equity), the Company recorded the consideration received from the issuance of the warrants as additional paid-in capital on the Company’s consolidated balance sheets. The Pre-Funded Warrants are exercisable at any time after the date of issuance. A holder of Pre-Funded Warrants may not exercise the Pre-Funded Warrant if the holder, together with its affiliates, would beneficially own more than 9.99 % of the number of shares of the Company’s common stock outstanding immediately after giving effect to such exercise. A holder of Pre-Funded Warrants may increase or decrease this percentage not in excess of 19.99 % by providing at least 61 days’ prior notice to the Company. As of December 31, 2023 , there were 257,310 Pre-Funded Warrants outstanding. Stock Options and Restricted Stock Unit Awards Stock Options. The following table summarizes stock option activity and related information under all equity plans for the year ended December 31, 2023: Options Weighted Weighted Aggregate Outstanding at December 31, 2022 7,267,226 $ 22.37 Granted 5,875,000 6.39 Exercised ( 93,787 ) 3.24 Cancelled ( 3,197,598 ) 20.26 Outstanding at December 31, 2023 9,850,841 $ 13.71 6.83 $ 903 Options vested and expected to vest at December 31, 2023 9,850,841 $ 13.71 6.83 $ 903 Options exercisable at December 31, 2023 6,297,349 $ 15.81 5.56 $ 392 For the years ended December 31, 2023 and 2022, the weighted average grant date fair value of stock options granted per share was equal to $ 4.83 and $ 24.07 , respectively. As of December 31, 2023 and 2022, the unrecognized compensation cost related to outstanding options was $ 23.0 million and $ 35.1 million, respectively, which was expected to be recognized as expense over approximately 1.9 years and 2.2 years, respectively. The total intrinsic value, which is the amount by which the exercise price was exceeded by the price of the Company’s common stock on the date of exercise, of stock options exercised during the years ended December 31, 2023 and 2022, was $ 0.3 million and $ 23.8 million, respectively. Total cash received upon the exercise of stock options was $ 0.3 million for the year ended December 31, 2023. Restricted Stock Units. The following table summarizes restricted stock unit activity and related information under all equity plans for the year ended December 31, 2023: Number of Weighted Weighted Aggregate Outstanding at December 31, 2022 5,862,733 $ 48.13 Granted 1,161,540 6.68 Vested ( 1,071,167 ) 42.71 Cancelled ( 2,888,019 ) 44.12 Outstanding at December 31, 2023 3,065,087 $ 37.96 2.59 $ 11,463 Restricted stock units expected to vest at December 31, 2023 2,044,470 $ 28.74 2.38 $ 7,646 As of December 31, 2023 and 2022, the unrecognized compensation cost related to outstanding restricted stock units (excluding those with unachieved performance-based conditions) was $ 38.3 million and $ 137.7 million, respectively, which was expected to be recognized as expense over approximately 2.0 years and 2.8 years, respectively. During the year ended December 31, 2021, 1,997,377 performance-based restricted stock units (PRSUs) were granted, none of which have vested. No PRSUs were granted during the years ended December 31, 2023 and 2022. There were 1,020,617 and 1,797,619 PRSUs outstanding at December 31, 2023 and 2022, respectively. Stock-Based Compensation Expense The allocation of stock-based compensation for all stock awards is as follows (in thousands): Years Ended 2023 2022 Research and development $ 20,849 $ 51,103 General and administrative 22,610 27,630 Total stock-based compensation expense $ 43,459 $ 78,733 Stock Option Grants Valuation. The weighted-average assumptions used in the Black-Scholes option pricing model to determine the fair value of the employee and nonemployee stock option grants were as follows: Years Ended 2023 2022 Risk–free interest rate 3.8 % 1.9 % Expected volatility 89.3 % 76.2 % Expected term (in years) 6.5 5.8 Expected dividend yield 0.0 % 0.0 % Risk-free interest rate. The Company bases the risk-free interest rate assumption on observed interest rates appropriate for the expected term of the stock option grants. Expected dividend yield. The Company bases the expected dividend yield assumption on the fact that it has never paid cash dividends and has no present intention to pay cash dividends. Expected volatility. The Company based the expected volatility on the historical volatility of its common stock over the most recent period commensurate with the estimated expected term of the Company’s stock options, as the Company determined there was sufficient operating history and company-specific historical volatility to estimate the expected volatility. Expected term. The expected term represents the period of time that options are expected to be outstanding. The Company estimated the expected term using historical experience and anticipated future exercise behavior. Common Stock Reserved for Future Issuance Common stock reserved for future issuance is as follows: December 31, 2023 2022 Convertible preferred stock (if converted) 13,805,540 13,972,745 Common stock options 9,850,841 7,267,226 Restricted stock units 3,065,087 5,862,733 Awards available under the 2022 Plan 8,633,496 10,274,169 Awards available under the Inducement Plan 689,750 741,000 Employee stock purchase plan — 729,000 Total 36,044,714 38,846,873

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	10. Income Taxes The following is a reconciliation of the Company’s expected federal income tax provision (benefit) to the actual income tax provision (in thousands): Years Ended December 31, 2023 2022 Tax computed at federal statutory rate $ ( 33,794 ) $ ( 59,161 ) State tax, net of federal tax benefit ( 4,851 ) ( 11,109 ) Non-deductible compensation 25 2,086 Permanent differences ( 2,305 ) ( 1,340 ) Stock compensation 12,801 3,356 R&D tax credits ( 5,773 ) ( 14,484 ) Reserve for uncertain tax positions 4,254 12,564 Other 1,928 ( 1,376 ) Valuation allowance 27,715 69,464 Income tax expense $ — $ — Significant components of the Company’s deferred tax assets are summarized as follows (in thousands): December 31, 2023 2022 Deferred tax assets: Capitalized R&D expense $ 134,209 $ 127,250 Net operating losses 112,810 84,608 R&D tax credits 55,492 49,736 Intangible asset amortization 9,220 8,012 Deferred revenue 144 8,714 Stock compensation 8,322 13,128 Lease liability 21,761 22,961 Other 672 2,526 Total deferred tax assets 342,630 316,935 Deferred tax liabilities: Depreciation ( 5,639 ) ( 6,814 ) Right-of-use assets ( 13,029 ) ( 13,874 ) Total deferred tax liabilities ( 18,668 ) ( 20,688 ) Net of deferred tax assets and liabilities 323,962 296,247 Valuation allowance ( 323,962 ) ( 296,247 ) Net deferred tax assets $ — $ — A valuation allowance of $ 324.0 million and $ 296.2 million at December 31, 2023 and 2022, respectively, has been established to offset the deferred tax assets, as realization of such assets is uncertain. At December 31, 2023, the Company had federal and California net operating loss (NOL) carryforwards of $ 526.4 million and $ 522.1 million, respectively, which may be available to offset future taxable income. The federal and California NOL carryforwards begin to expire in 2027 and 2028 , respectively, unless previously utilized. At December 31, 2023 , the Company had federal and California research and development (R&D) credit carryforwards of $ 40.3 million and $ 34.7 million, respectively. The federal R&D tax credit carryforwards will begin to expire in 2035 unless previously utilized. The California R&D credit carryforwards will carry forward indefinitely. Under Sections 382 and 383 of the Internal Revenue Code of 1986, as amended, (the Code), substantial changes in the Company’ s ownership may limit the amount of net operating loss and research and development credit carryforwards that could be used annually in the future to offset taxable income. The tax benefits related to future utilization of federal and state net operating loss carryforwards, credit carryforwards, and other deferred tax assets may be limited or lost if cumulative changes in ownership exceeds 50 % within any three-year period. The Company completed a study to assess whether an ownership change, as defined by Section 382 of the Code, had occurred from the Company’s formation through December 31, 2015. Based upon this study, the Company determined that several ownership changes had occurred. Accordingly, the Company reduced its deferred tax assets related to the federal NOL carryforwards and the federal R&D credit carryforwards that are anticipated to expire unused as a result of these ownership changes. These tax attributes were excluded from deferred tax assets with a corresponding reduction of the valuation allowance with no net effect on income tax expense or the effective tax rate. The Company updated the study December 31, 2023 and concluded there were no ownership changes during 2023. Future ownership changes may further limit the Company’s ability to utilize its remaining tax attributes. The Company files income tax returns in the United States, various state jurisdictions, and the Netherlands with varying statutes of limitations. The Company currently has no years under examination by any jurisdiction; however, the Company is subject to income tax examination by federal and state tax authorities for years beginning in 2020 and 2019 , respectively. However, to the extent allowed by law, the taxing authorities may have the right to examine prior periods where NOLs and tax credits were generated and carried forward, and make adjustments up to the amount of the carryforwards. The change in the Company’s unrecognized tax benefits is summarized as follows (in thousands): December 31, 2023 2022 Beginning unrecognized tax benefits $ 52,767 $ 37,255 Increase related to current year tax positions 9,724 9,101 Increase related to prior year tax positions 90 6,411 Decrease related to prior year tax positions ( 2,901 ) — Ending unrecognized tax benefits $ 59,680 $ 52,767 The Company does no t anticipate that the amount of unrecognized tax benefits as of December 31, 2023 will significantly change within the next twelve months. Due to the valuation allowance recorded against the Company’s deferred tax assets, no ne of the total unrecognized tax benefits as of December 31, 2023 would reduce the effective tax rate if recognized. The Company has not recognized interest or penalties related to income tax matters in its consolidated statements of operations and comprehensive loss since inception.

Employee Benefits

Employee Benefits	12 Months Ended
	Dec. 31, 2023
Retirement Benefits [Abstract]
Employee Benefits	11. Employee Benefits Effective January 1, 2009, the Company adopted a defined contribution 401(k) plan for employees who are at least 21 years of age. Employees are eligible to participate in the plan beginning on the first day of the calendar quarter following date of hire. Under the terms of the plan, employees may make voluntary contributions as a percent of compensation. The Company makes discretionary contributions to the 401(k) Plan equal to 100 percent of each employee’s pretax contributions up to 20 percent of the IRS Standard Limit. The Company ’ s total contributions to the 401(k) Plan were $ 1.9 million and $ 1.3 million for the years ended December 31, 2023 and 2022 , respectively.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	12. Commitments and Contingencies License Agreements The Company has entered into exclusive license agreements with certain academic institutions and universities pursuant to which the Company acquired certain intellectual property. Pursuant to each agreement, as consideration for an exclusive license to the intellectual property, the Company paid a license fee, reimbursed the institution for historical patent costs and, in certain instances, issued the institution shares of restricted common stock. Additionally, under each agreement, the institution is generally eligible to receive future consideration including, but not limited to, annual maintenance fees, royalties, milestone payments and sublicensing fees. Each of the license agreements is generally cancelable by the Company, given appropriate prior written notice. Minimum annual payments to maintain these cancelable licenses total an aggregate of $ 0.4 million. See Note 2 for additional information on certain licenses. Litigation On January 20, 2023, a purported stockholder of the Company filed a securities class action lawsuit against the Company and certain of its officers captioned Hadian v. Fate Therapeutics, Inc. et al. in the U.S. District Court for the Southern District of California (the Securities Action). On May 4, 2023, the court appointed a different purported stockholder of the Company to serve as lead plaintiff in the Securities Action. On July 24, 2023, the lead plaintiff filed an amended complaint. The amended complaint alleges that the Company violated the federal securities laws by making allegedly false and/or misleading statements and/or omissions in its public disclosures dating back to August 2020 relating to our collaboration agreement with Janssen Biotech, Inc. (the Janssen Agreement), potential product candidates subject to the Janssen Agreement, and the termination of the Janssen Agreement. On September 22, 2023, we filed a motion to dismiss the amended complaint in its entirety. Briefing on our motion to dismiss was completed on December 6, 2023. The court may, in its discretion, either hold oral argument on the motion to dismiss or issue a ruling on the motion based upon the parties’ briefing. We intend to continue to vigorously defend against this action. On June 2, 2023, a derivative complaint, captioned Guarino v. Wolchko, et al., was filed by a purported stockholder of the Company in the U.S. District Court for the Southern District of California. The derivative lawsuit names members of our board of directors and certain officers as defendants. The Company is named as a nominal defendant. The plaintiff asserts derivative claims arising out of substantially the same alleged facts and circumstances as the Securities Action. The complaint asserts claims for breach of fiduciary duty, unjust enrichment, abuse of control, gross mismanagement, waste of corporate assets, and violation of federal securities laws. On August 14, 2023, the court stayed the derivative lawsuit pending the court’s decision on our motion to dismiss in the Securities Action filed September 22, 2023. We intend to vigorously defend against this action. From time to time, the Company may be involved in various other lawsuits, legal proceedings, or claims that arise in the ordinary course of business. Management believes there are no claims or actions pending against the Company as of December 31, 2023 , which will have, individually or in the aggregate, a material adverse effect on its business, liquidity, financial position, or results of operations. Litigation, however, is subject to inherent uncertainties, and an adverse result in these or other matters may arise from time to time that may harm the Company’s business.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2023
Subsequent Events [Abstract]
Subsequent Events	13. Subsequent Events California Institute for Regenerative Medicine Award On February 22, 2024, the Company was awarded a $ 7.9 m illion grant from the California Institute for Regenerative Medicine (CIRM) to support the conduct of the Company’s Phase 1 study of FT819 in patients with SLE.

Organization and Summary of S_2

Organization and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Use of Estimates	Use of Estimates The Company’s consolidated financial statements are prepared in accordance with United States generally accepted accounting principles (U.S. GAAP). The preparation of the Company’s consolidated financial statements requires it to make estimates and assumptions that impact the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities in the Company’s consolidated financial statements and accompanying notes. The most significant estimates in the Company’s consolidated financial statements relate to its stock appreciation milestone obligations, contracts containing leases, and accrued expenses. Although these estimates are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions.
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of the Company and its subsidiaries. To date, the aggregate operations of these subsidiaries have not been significant and all intercompany transactions and balances have been eliminated in consolidation.
Segment Reporting	Segment Reporting Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business in one operating and reportable segment.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company’s financial instruments consist primarily of cash and cash equivalents, marketable securities, accounts receivable, stock price appreciation milestones, accounts payable, and accrued liabilities. The carrying amounts of accounts receivable, accounts payable and accrued liabilities are considered to be representative of their respective fair values because of the relatively short-term nature of those instruments. The accounting guidance defines fair value, establishes a consistent framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring or nonrecurring basis. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, the accounting guidance establishes a three- tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows: Level 1: Observable inputs such as quoted prices in active markets; Level 2: Inputs, other than the quoted prices in active markets, that are observable either directly or indirectly; and Level 3: Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. Assets and liabilities are classified based on the lowest level of input that is significant to the fair value measurements. The Company reviews the fair value hierarchy classification on a quarterly basis.
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted Cash Cash and cash equivalents include cash in readily available checking and savings accounts, money market accounts and money market funds. The Company considers all highly liquid investments with an original maturity of three months or less from the date of purchase to be cash equivalents. The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the consolidated balance sheets that sum to the total of the same such amounts shown in the consolidated statements of cash flows as of December 31, 2023 and 2022 (in thousands): Years Ended December 31, 2023 2022 Cash and cash equivalents $ 41,870 $ 61,333 Restricted cash 15,177 15,227 Total cash, cash equivalents, and restricted cash shown in the consolidated statement of cash flows $ 57,047 $ 76,560 For the years ended December 31, 2023 and 2022 , the restricted cash balance includes cash-collateralized irrevocable standby letters of credit for $ 15.2 million associated with the Company’s facilities leases .
Investments	Investments Investments are accounted for as available-for-sale securities and are carried at fair value on the consolidated balance sheets. Upon initial recognition of the investment and at each reporting period, the Company evaluates whether any unrealized losses on investments are attributable to a credit loss or other factors. Any unrealized losses attributable to credit loss are recorded through an allowance for credit losses, limited to the amount by which the fair value is below amortized cost, with the offsetting amount recorded in other income or expense in the consolidated statement of operations and comprehensive loss. Unrealized losses not attributable to an expected credit loss and unrealized gains on investments are recorded in other comprehensive income (loss) on the consolidated statements of operations and comprehensive loss. Realized gains and losses, if any, on investments classified as available-for-sale securities are included in other income or expense. The amortized cost of investments classified as available-for-sale debt securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion are included in interest income. The cost of securities sold is based on the specific identification method. Interest and dividends on securities classified as available-for-sale are included in interest income.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments, which potentially subject the Company to a significant concentration of credit risk, consist primarily of cash and cash equivalents and investments. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts and management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits and investments are held.
Property and Equipment	Property and Equipment Property and equipment are recorded at cost and depreciated using the straight-line method over the estimated useful lives of the assets (generally two to five years ) and generally consist of furniture and fixtures, computers, scientific and office equipment, and in-process costs related to facilities construction. Repairs and maintenance costs are charged to expense as incurred.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. An impairment loss is recorded if and when events and circumstances indicate that assets might be impaired and the undiscounted cash flows estimated to be generated by those assets are less than the carrying amount of those assets. If the carrying amount is not recoverable, the Company measures the amount of any impairment by comparing the carrying value of the asset to the present value of the expected future cash flows associated with the use of the asset. While the Company’s current and historical operating losses and negative cash flows are indicators of impairment, management believes that future cash flows to be received support the carrying value of its long-lived assets and, accordingly, has not recognized any impairment losses since the Company’ s inception.
Leases	Leases The Company determines if a contract contains a lease at the inception of the contract. The Company currently has leases related to its facilities leased for office and laboratory space, which are classified as operating leases. These leases result in operating right-of-use (ROU) assets, current operating lease liabilities, and non-current operating lease liabilities in the Company’s consolidated balance sheets. The Company does not have any financing leases. Leases with a term of 12 months or less are considered short-term and ROU assets and lease obligations are not recognized. Payments associated with short-term leases are expensed on a straight-line basis over the lease term. Lease liabilities represent an obligation to make lease payments arising from the lease and ROU assets represent the right to use the underlying asset identified in the lease for the lease term. Lease liabilities are measured at the present value of the lease payments not yet paid discounted using the discount rate for the lease established at the lease commencement date. To determine the present value, the implicit rate is used when readily determinable. For those leases where the implicit rate is not provided, the Company determines an incremental borrowing rate based on the information available at the lease commencement date in determining the present value of lease payments. ROU assets are measured as the present value of the lease payments and also include any prepaid lease payments made and any other indirect costs incurred, and exclude any lease incentives received. Lease terms may include the impact of options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease expense for operating leases is recognized on a straight-line basis over the lease term. The Company aggregates all lease and non-lease components for each class of underlying assets into a single lease component.
Collaborative Arrangements	Collaborative Arrangements The Company analyzes its collaboration arrangements to assess whether they are within the scope of ASC Topic 808, Collaborative Arrangements (ASC 808), to determine whether such arrangements involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards that are dependent on the commercial success of such activities. To the extent the arrangement is within the scope of ASC 808, the Company assesses whether aspects of the arrangement between the Company and its collaboration partner are within the scope of other accounting literature, including ASC Topic 606, Revenue from Contracts with Customers (ASC 606). If it is concluded that some or all aspects of the arrangement represent a transaction with a customer, the Company will account for those aspects of the arrangement within the scope of ASC 606. ASC 808 provides guidance for the presentation and disclosure of transactions in collaborative arrangements, but it does not provide recognition or measurement guidance. Therefore, if the Company concludes a counterparty to a transaction is not a customer or otherwise not within the scope of ASC 606, the Company considers the guidance in other accounting literature as applicable or by analogy to account for such transaction. The classification of transactions under the Company’s arrangements is determined based on the nature and contractual terms of the arrangement along with the nature of the operations of the participants.
Revenue Recognition	Revenue Recognition The Company analyzes its collaboration arrangements to assess whether they are within the scope of ASC 808, to determine whether such arrangements involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards that are dependent on the commercial success of such activities. If the Company concludes that some or all aspects of the arrangement represent a transaction with a customer, the Company accounts for those aspects of the arrangement within the scope of ASC 606. For arrangements attributable to ASC 606, the Company recognizes revenue in a manner that depicts the transfer of control of a product or a service to a customer and reflects the amount of the consideration the Company is entitled to receive in exchange for such product or service. In doing so, the Company follows a five-step approach: (i) identify the contract with a customer, (ii) identify the performance obligations in the contract, (iii) determine the transaction price, (iv) allocate the transaction price to the performance obligations, and (v) recognize revenue when (or as) the customer obtains control of the product or service.
Stock Price Appreciation Milestones	Stock Price Appreciation Milestones The Company estimates the fair value of the stock price appreciation milestones associated with the Amended and Restated Exclusive License Agreement with Memorial Sloan Kettering Cancer Center (MSKCC) using a Monte Carlo simulation model, which relies on the Company’s current stock price as well as significant estimates and assumptions to determine the estimated liability associated with the contingent milestone payments. The Company accounts for the fair value of the stock price appreciation milestones in accordance with ASC 815, Derivatives and Hedging, with fair value marked to market at each reporting date. The assumptions used to calculate the fair value of the stock price appreciation milestones are subject to a significant amount of judgment including the probability of achieving a specified clinical milestone, the expected volatility of the Company’s common stock, the risk-free interest rate, and the estimated term, which is based in part on the last valid patent claim date. The Company remeasures the fair value of the stock price appreciation milestones at each balance sheet date, with changes in fair value recorded in earnings as non-operating income or expense on the consolidated statements of operations and comprehensive loss.
Stock-Based Compensation	Stock-Based Compensation Stock-based compensation expense represents the cost of the grant date fair value of employee stock option and restricted stock unit grants recognized over the requisite service period of the awards (usually the vesting period) on a straight-line basis. Performance-based stock units/awards represent a right to receive a certain number of shares of the Company’s common stock based on the achievement of corporate performance goals and continued employment during the vesting period. At each reporting period, and to the extent achievement of one or any of the performance conditions is probable, the Company reassesses the probability of the achievement of such corporate performance goals and any increase or decrease in share-based compensation expense resulting from an adjustment in the estimated shares to be released is treated as a cumulative catch-up in the period of adjustment. For stock awards for which vesting is subject to both performance-based milestones and market conditions, expense is recorded over the derived service period after the point when the achievement of the performance-based milestone is probable or the performance condition has been achieved. The Company estimates the fair value of stock option grants using the Black-Scholes option pricing model, with the exception of option grants for which vesting is subject to both performance-based milestones and market conditions, which are valued using a lattice-based model. The fair value of restricted stock units, including performance-based restricted stock units, is based on the closing price of the Company’s common stock as reported on The Nasdaq Global Market on the date of grant. The Company recognizes forfeitures for all awards as such forfeitures occur.
Income Taxes	Income Taxes The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. The Company recognizes net deferred tax assets to the extent that the Company believes these assets are more likely than not to be realized. In making such a determination, management considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If management determines that the Company would be able to realize its deferred tax assets in the future in excess of their net recorded amount, management would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. The Company records uncertain tax positions on the basis of a two-step process whereby (1) management determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more- likely-than-not recognition threshold, management recognizes the largest amount of tax benefit that is more than 50 percent likely to be realized upon ultimate settlement with the related tax authority. The Company recognizes interest and penalties related to unrecognized tax benefits within income tax expense. Any accrued interest and penalties are included within the related tax liability.
Employee Retention credit	Employee Retention Credit The CARES Act provides an employee retention credit (ERC), which is a refundable tax credit against certain employment taxes of up to $ 5,000 per employee for eligible employers. The tax credit is equal to 50 % of qualified wages paid to employees during a quarter, capped at $ 10,000 of qualified wages per employee through December 31, 2020. Additional relief provisions were passed by the United States government, which extend and slightly expand the qualified wage caps on these credits through December 31, 2021. Based on these additional provisions, the tax credit is now equal to 70 % of qualified wages paid to employees during a quarter, and the limit on qualified wages per employee has been increased to $ 10,000 of qualified wages per quarter. The Company qualifies for the tax credit under the CARES Act and expects to continue to receive additional tax credits under the additional relief provisions for qualified wages through December 31, 2021. In connection with the CARES Act, the Company adopted a policy to recognize the employee retention credit when received and include in other income in the statement of operations. T he Company received a cash payment and recorded $ 5.1 million and $ 0.5 million of other income during the years ended December 31, 2023 and 2022, respectively .
Comprehensive Loss	Comprehensive Loss Comprehensive loss is defined as a change in equity during a period from transactions and other events and circumstances from non‑owner sources. Other comprehensive loss includes unrealized gains and losses on available-for-sale securities.
Net Loss Per Common Share	Net Loss Per Common Share Basic net loss per common share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period, without consideration for common stock equivalents. The Pre-Funded Warrants associated with the January 2021 public equity offering (see Note 9) are considered outstanding shares in the basic earnings per share calculation given their nominal exercise price. Dilutive common stock equivalents comprise convertible preferred stock, warrants for the purchase of common stock, and common stock options and restricted stock units outstanding under the Company’s stock option plans. For all periods presented, there is no difference in the number of common shares used to calculate basic and diluted common shares outstanding due to the Company’s net loss position. Potentially dilutive securities that are not included in the calculation of diluted net loss per common share because to do so would be anti-dilutive are as follows (in common stock equivalent shares): As of December 31, 2023 2022 Common stock options 9,850,841 7,267,226 Restricted stock units 3,065,087 5,862,733 Series A convertible preferred stock (if converted) 13,805,540 13,972,745 Total 26,721,468 27,102,704
Going Concern Assessment	Going Concern Assessment Substantial doubt about an entity’s ability to continue as a going concern exists when relevant conditions and events, considered in the aggregate, indicate that it is probable that the entity will be unable to meet its obligations as they become due within one year from the financial statement issuance date. The Company determined that there are no conditions or events that raise substantial doubt about its ability to continue as a going concern for a period of at least twelve months from the date of issuance of these financial statements .
Restructuring	Restructuring In January 2023, the Company implemented a corporate restructuring to streamline operations, reduce operating expenses, extend cash runway and focus resources on the Company’s most promising programs. In connection with the restructuring, the Company reduced its workforce by 60 %. Affected employees were informed on January 5, 2023. The restructuring was completed by March 31, 2023. The Company incurred charges of $ 12.9 million during the year ended December 31, 2023 for severance and other employee termination-related costs, of which $ 10.9 million were related to research and development expenses and $ 2.0 million were related to general and administrative expenses. All restructuring and related expenses have been fully recognized by the Company.

Organization and Summary of S_3

Organization and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Reconciliation of Cash, Cash Equivalents, and Restricted Cash	The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the consolidated balance sheets that sum to the total of the same such amounts shown in the consolidated statements of cash flows as of December 31, 2023 and 2022 (in thousands): Years Ended December 31, 2023 2022 Cash and cash equivalents $ 41,870 $ 61,333 Restricted cash 15,177 15,227 Total cash, cash equivalents, and restricted cash shown in the consolidated statement of cash flows $ 57,047 $ 76,560
Schedule of Anti-Dilutive Securities not Included in Calculation of Diluted Net Loss Per Common Share	Potentially dilutive securities that are not included in the calculation of diluted net loss per common share because to do so would be anti-dilutive are as follows (in common stock equivalent shares): As of December 31, 2023 2022 Common stock options 9,850,841 7,267,226 Restricted stock units 3,065,087 5,862,733 Series A convertible preferred stock (if converted) 13,805,540 13,972,745 Total 26,721,468 27,102,704

Collaboration and License Agr_2

Collaboration and License Agreements (Tables)	12 Months Ended
	Dec. 31, 2023
Collaboration And License Agreements Disclosure [Abstract]
Summary of All Possible Stock Price Appreciation Milestone Payments	The following table summarizes the common stock multiples and the stock price appreciation milestone payments under the terms of the agreement: Common stock multiple 5.0x 10.0x 15.0x Ten-trading day trailing average common stock price $ 50.18 $ 100.36 $ 150.54 Stock price appreciation milestone payment (in millions) $ 20.0 $ 30.0 $ 25.0
Schedule of Assumptions Used to Determine the Estimated Fair Value of the Stock Price Appreciation Milestone Payments	Year Ended Year Ended 2023 2022 Risk-free interest rate 4.0 % 4.0 % Expected volatility 84.0 % 78.1 % Estimated term (in years) 15.0 16.0 Closing stock price as of measurement date $ 3.74 $ 10.09

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2023
Investments [Abstract]
Summary of Investments	The following table summarizes the Company’s investments accounted for as available-for-sale securities as of December 31, 2023 and 2022 (in thousands): Maturity Amortized Unrealized Unrealized Estimated December 31, 2023 Classified as current assets: Money market fund 1 or less $ 35,273 $ — $ — $ 35,273 U.S. Treasury debt securities 1 or less 82,811 ( 34 ) 27 82,804 Non-US government securities 1 or less 999 — — 999 Municipal securities 1 or less 5,000 ( 3 ) — 4,997 Corporate debt securities 1 or less 47,144 ( 51 ) 14 47,107 Commercial paper 1 or less 137,339 ( 62 ) 121 137,398 Total short-term investments $ 308,566 $ ( 150 ) $ 162 $ 308,578 Classified as non-current assets: Corporate debt securities Greater than 1 $ 977 $ — $ 3 $ 980 Total long-term investments $ 977 $ — $ 3 $ 980 December 31, 2022 Classified as current assets: Money market fund 1 or less $ 37,645 $ — $ — $ 37,645 U.S. Treasury debt securities 1 or less 86,221 ( 263 ) 37 85,995 Non-US government securities 1 or less 2,425 ( 2 ) — 2,423 Municipal securities 1 or less 18,963 ( 208 ) — 18,755 Corporate debt securities 1 or less 126,691 ( 1,138 ) 5 125,558 Commercial paper 1 or less 152,056 ( 230 ) 4 151,830 Total short-term investments $ 424,001 $ ( 1,841 ) $ 46 $ 422,206 Classified as non-current assets: Municipal securities Greater than 1 $ 5,000 $ ( 58 ) $ — $ 4,942 Total long-term investments $ 5,000 $ ( 58 ) $ — $ 4,942

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Schedule of Assets Measured at Fair Value on Recurring Basis	The following tables presents the Company’s financial assets and liabilities measured at fair value on a recurring basis as of December 31, 2023 and 2022 (in thousands): Fair Value Measurements at Total Quoted Prices Significant Significant As of December 31, 2023: Financial assets: Money market fund $ 35,273 $ 35,273 $ — $ — U.S. Treasury debt securities 82,804 82,804 — — Non-US government securities 999 — 999 — Municipal securities 4,997 — 4,997 — Corporate debt securities 48,087 — 48,087 — Commercial paper 137,398 — 137,398 — Total assets measured at fair value on a recurring basis $ 309,558 $ 118,077 $ 191,481 $ — Financial liabilities: Stock price appreciation milestones $ 1,346 $ — $ — $ 1,346 Total financial liabilities measured at fair value on a recurring basis $ 1,346 $ — $ — $ 1,346 As of December 31, 2022: Financial assets: Money market fund $ 37,645 $ 37,645 $ — $ — U.S. Treasury debt securities 85,995 85,995 — — Non-US government securities 2,423 — 2,423 — Municipal securities 23,697 — 23,697 — Corporate debt securities 125,558 — 125,558 — Commercial paper 151,830 — 151,830 — Total assets measured at fair value on a recurring basis $ 427,148 $ 123,640 $ 303,508 $ — Financial liabilities: Stock price appreciation milestones $ 3,861 $ — $ — $ 3,861 Total financial liabilities measured at fair value on a recurring basis $ 3,861 $ — $ — $ 3,861
Summary of Changes in the Fair Value of the Company’s Level 3 Enterprise Fair Value Milestone Payment Liability	The following table presents the changes in fair value of the Company’s Level 3 stock price appreciation milestones liability (in thousands): Balance at December 31, 2021 $ 24,168 Changes in fair value of stock price appreciation milestones liability ( 20,307 ) Balance at December 31, 2022 $ 3,861 Changes in fair value of stock price appreciation milestones liability ( 2,515 ) Balance at December 31, 2023 $ 1,346

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Schedule of property and equipment	Property and equipment consist of the following (in thousands): December 31, 2023 2022 Furniture and fixtures $ 1,309 $ 1,209 Computer and office equipment 3,132 2,937 Software 2,130 2,122 Leasehold improvements—building 59,038 56,782 Scientific equipment 78,853 77,354 Total property and equipment, gross 144,462 140,404 Less accumulated depreciation and amortization ( 47,626 ) ( 30,384 ) Total property and equipment, net $ 96,836 $ 110,020

Accrued Expenses and Long-Ter_2

Accrued Expenses and Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2023
Accrued Expenses And Long Term Debt Disclosure [Abstract]
Schedule of accrued expenses	Current accrued expenses consist of the following (in thousands): December 31, 2023 2022 Accrued payroll and other employee benefits $ 10,563 $ 17,899 Accrued clinical trial related costs 8,833 16,858 Accrued other 8,118 19,175 Total current accrued expenses $ 27,514 $ 53,932

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Schedule of Components of Lease Expense	The components of lease expense for the years ended December 31, 2023 and 2022 were as follows (in thousands): Years Ended 2023 2022 Straight-line lease expense $ 13,159 $ 15,010 Variable lease expense 2,250 2,614 Total operating lease expense $ 15,409 $ 17,624
Schedule of Future Minimum Payments Under Non-cancelable Operating Leases	Future undiscounted minimum payments under the Company’s operating leases as of December 31, 2023 are as follows (in thousands): Operating Years Ending December 31, 2024 $ 14,659 2025 15,087 2026 15,540 2027 16,006 2028 15,057 Thereafter 86,579 Total undiscounted lease payments $ 162,928 Less: imputed interest ( 59,392 ) Total lease liability $ 103,536
Schedule of sublease Income	Sublease income is recognized in other income. Sublease income for the years ended December 31, 2023 and 2022 was as follows (in thousands): Years Ended 2023 2022 Sublease income $ 729 $ —

Convertible Preferred Stock a_2

Convertible Preferred Stock and Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2023
Convertible Preferred Stock And Stockholders Deficit Disclosure [Abstract]
Summary of stock option activity and related information under all equity plans	The following table summarizes stock option activity and related information under all equity plans for the year ended December 31, 2023: Options Weighted Weighted Aggregate Outstanding at December 31, 2022 7,267,226 $ 22.37 Granted 5,875,000 6.39 Exercised ( 93,787 ) 3.24 Cancelled ( 3,197,598 ) 20.26 Outstanding at December 31, 2023 9,850,841 $ 13.71 6.83 $ 903 Options vested and expected to vest at December 31, 2023 9,850,841 $ 13.71 6.83 $ 903 Options exercisable at December 31, 2023 6,297,349 $ 15.81 5.56 $ 392
Summary of restricted stock unit activity and related information under all equity plans	The following table summarizes restricted stock unit activity and related information under all equity plans for the year ended December 31, 2023: Number of Weighted Weighted Aggregate Outstanding at December 31, 2022 5,862,733 $ 48.13 Granted 1,161,540 6.68 Vested ( 1,071,167 ) 42.71 Cancelled ( 2,888,019 ) 44.12 Outstanding at December 31, 2023 3,065,087 $ 37.96 2.59 $ 11,463 Restricted stock units expected to vest at December 31, 2023 2,044,470 $ 28.74 2.38 $ 7,646
Schedule of allocation of stock-based compensation for all stock awards	The allocation of stock-based compensation for all stock awards is as follows (in thousands): Years Ended 2023 2022 Research and development $ 20,849 $ 51,103 General and administrative 22,610 27,630 Total stock-based compensation expense $ 43,459 $ 78,733
Schedule of weighted-average assumptions used to determine the fair value of employee and nonemployee stock option grants	The weighted-average assumptions used in the Black-Scholes option pricing model to determine the fair value of the employee and nonemployee stock option grants were as follows: Years Ended 2023 2022 Risk–free interest rate 3.8 % 1.9 % Expected volatility 89.3 % 76.2 % Expected term (in years) 6.5 5.8 Expected dividend yield 0.0 % 0.0 %
Schedule of common stock reserved for future issuance	Common stock reserved for future issuance is as follows: December 31, 2023 2022 Convertible preferred stock (if converted) 13,805,540 13,972,745 Common stock options 9,850,841 7,267,226 Restricted stock units 3,065,087 5,862,733 Awards available under the 2022 Plan 8,633,496 10,274,169 Awards available under the Inducement Plan 689,750 741,000 Employee stock purchase plan — 729,000 Total 36,044,714 38,846,873

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Schedule of reconciliation of the Company's expected federal income tax provision (benefit) to the actual income tax provision	The following is a reconciliation of the Company’s expected federal income tax provision (benefit) to the actual income tax provision (in thousands): Years Ended December 31, 2023 2022 Tax computed at federal statutory rate $ ( 33,794 ) $ ( 59,161 ) State tax, net of federal tax benefit ( 4,851 ) ( 11,109 ) Non-deductible compensation 25 2,086 Permanent differences ( 2,305 ) ( 1,340 ) Stock compensation 12,801 3,356 R&D tax credits ( 5,773 ) ( 14,484 ) Reserve for uncertain tax positions 4,254 12,564 Other 1,928 ( 1,376 ) Valuation allowance 27,715 69,464 Income tax expense $ — $ —
Summary of significant components of the Company's deferred tax assets	Significant components of the Company’s deferred tax assets are summarized as follows (in thousands): December 31, 2023 2022 Deferred tax assets: Capitalized R&D expense $ 134,209 $ 127,250 Net operating losses 112,810 84,608 R&D tax credits 55,492 49,736 Intangible asset amortization 9,220 8,012 Deferred revenue 144 8,714 Stock compensation 8,322 13,128 Lease liability 21,761 22,961 Other 672 2,526 Total deferred tax assets 342,630 316,935 Deferred tax liabilities: Depreciation ( 5,639 ) ( 6,814 ) Right-of-use assets ( 13,029 ) ( 13,874 ) Total deferred tax liabilities ( 18,668 ) ( 20,688 ) Net of deferred tax assets and liabilities 323,962 296,247 Valuation allowance ( 323,962 ) ( 296,247 ) Net deferred tax assets $ — $ —
Summary of the change in the Company's unrecognized tax benefits	The change in the Company’s unrecognized tax benefits is summarized as follows (in thousands): December 31, 2023 2022 Beginning unrecognized tax benefits $ 52,767 $ 37,255 Increase related to current year tax positions 9,724 9,101 Increase related to prior year tax positions 90 6,411 Decrease related to prior year tax positions ( 2,901 ) — Ending unrecognized tax benefits $ 59,680 $ 52,767

Organization and Summary of S_4

Organization and Summary of Significant Accounting Policies (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Jan. 31, 2023	Dec. 31, 2023 USD ($) Disbursement	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Organization and summary of significant accounting policies
Percentage of number of employee reduced	60%
Research and development expense		$ 10,900
General and administrative expense		2,000
Low Range Restructuring Costs		$ 12,900
Number of operating segments | Disbursement		1
Number of reportable segments | Disbursement		1
Letters of credit outstanding amount		$ 15,200	$ 15,200
Maximum
Organization and summary of significant accounting policies
Short-term leases term excluded from calculation of ROU and lease liabilities		12 months
Employee Retention Credit [Member]
Organization and summary of significant accounting policies
Percentage Of Tax Credit				70%	50%
Payments To Employees				$ 10,000	$ 10,000
Other Income		$ 5,100	$ 500
Employee Retention Credit [Member] | Maximum
Organization and summary of significant accounting policies
RefundableTaxCredit					$ 5,000

Organization and Summary of S_5

Organization and Summary of Significant Accounting Policies (Details 1) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents	$ 41,870	$ 61,333
Restricted cash	15,177	15,227
Total cash, cash equivalents, and restricted cash shown in the consolidated statement of cash flows	$ 57,047	$ 76,560	$ 148,810

Organization and Summary of S_6

Organization and Summary of Significant Accounting Policies (Details 2) - Scientific Equipment	Dec. 31, 2023
Minimum
Property and equipment
Estimated useful lives	2 years
Maximum
Property and equipment
Estimated useful lives	5 years

Organization and Summary of S_7

Organization and Summary of Significant Accounting Policies (Details 3) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Net Loss per Common Share [Abstract]
Uncertain tax position description	more than 50 percent
Anti-dilutive securities (in shares)	26,721,468	27,102,704
Common Stock Options
Net Loss per Common Share [Abstract]
Anti-dilutive securities (in shares)	9,850,841	7,267,226
Restricted Stock Units (RSUs)
Net Loss per Common Share [Abstract]
Anti-dilutive securities (in shares)	3,065,087	5,862,733
Series A Convertible Preferred Stock (if converted)
Net Loss per Common Share [Abstract]
Anti-dilutive securities (in shares)	13,805,540	13,972,745

Collaboration and License Agr_3

Collaboration and License Agreements (Details) - USD ($) $ / shares in Units, shares in Millions

1 Months Ended

12 Months Ended

Nov. 07, 2022

Apr. 02, 2020

Sep. 14, 2018

Sep. 14, 2018

Jun. 30, 2022

Jun. 30, 2020

Sep. 30, 2018

Dec. 31, 2023

Dec. 31, 2022

Nov. 30, 2023

Dec. 31, 2021

Dec. 31, 2020

Collaboration agreement

Collaboration contract asset

$ 0

$ 7,196,000

Revenue recognized

63,533,000

96,300,000

Commercial Option Exercise Member

Collaboration agreement

Revenue recognized

10,000,000

13,000,000

Associated with collaboration services

Collaboration agreement

Revenue recognized

1,300,000

Johnson Johnson Innovation J J D C Inc | Stock Purchase Agreement

Collaboration agreement

Upfront cash payment

$ 50,000,000

Company Received Payment

100,000,000

Equity method investment, underlying equity in net assets

50,000,000

Issuance of common stock during period for private placements (in shares)

1.8

Common stock per share

$ 28.31

Aggregate purchase price of common stock

$ 50,000,000

Equity premium per share

$ 9.93

Aggregate equity premium on shares

$ 16,000,000

Proceeds from private placement of common stock, net of issuance costs

$ 34,000,000

Janssen Biotech Inc

Collaboration agreement

Collaboration contract asset

17,100,000

Amortization of sublicense consideration

7,200,000

4,300,000

Revenue recognized

52,300,000

79,700,000

Deferred revenue

41,200,000

Janssen Biotech Inc | Research And Development

Collaboration agreement

Revenue recognized

11,100,000

42,300,000

Janssen Biotech Inc | Upfront Fee and Equity Premium

Collaboration agreement

Revenue recognized

31,200,000

23,100,000

Janssen Biotech Inc | Janssen Agreement

Collaboration agreement

Sublicense Consideration Represents an Asset Under ASC, Other Assets and Deferred Costs

17,100,000

Ono Pharmaceutical Company Ltd

Collaboration agreement

Transaction price of the agreement

$ 40,700,000

Non-refundable upfront payments recorded as deferred revenue

$ 10,000,000

Collaboration contract asset

7,800,000

Amortization of sublicense consideration

4,100,000

Revenue recognized

11,200,000

16,600,000

Research and development fees cash payments received

32,700,000

Option Exercise Payment

$ 12,500

Contra research and development expenses

8,000,000

Proceeds from related party

6,200,000

Aggregate research and development fees payments receivable

20,000,000

20,000,000

Collaborative arrangement potential additional milestones

30,700,000

30,700,000

Non-refundable upfront payments recorded as deferred revenue

$ 10,000,000

$ 10,000,000

Collaborative arrangement annual payments receivable recorded as deferred revenue

$ 5,000,000

Ono Pharmaceutical Company Ltd | Candidate 1

Collaboration agreement

Percentage of reduction on milestone payments

50%

Ono Pharmaceutical Company Ltd | Collaborative Arrangement | Research services

Collaboration agreement

Revenue recognized

11,200,000

2,500,000

Ono Pharmaceutical Company Ltd | Collaborative Arrangement | Upfront Fee

Collaboration agreement

Revenue recognized

1,600,000

Ono Pharmaceutical Company Ltd | Maximum | Candidate 2

Collaboration agreement

Aggregate milestone payments

$ 843,000,000

Ono Pharmaceutical Company Ltd | Maximum | Candidate 1

Collaboration agreement

Collaborative arrangement potential additional milestones

$ 29,300,000

$ 30,700,000

Ono Pharmaceutical Company Ltd | Minimum | Candidate 1

Collaboration agreement

Profits and losses sharing percentage

50%

Collaborative arrangement potential additional milestones

$ 9,300,000

$ 1,400,000

Ono Pharmaceutical Company Ltd | Ono Letter Agreement

Collaboration agreement

Revenue recognized

12,500,000

Deferred revenue

700,000

Milestone payments

$ 10,000,000

Ono Pharmaceutical Company Ltd | Ono Letter Agreement | Sublicense Consideration

Collaboration agreement

Sublicense consideration paid

7,800,000

Amended MSK License

Collaboration agreement

Stock price appreciation milestone, income

2,500,000

20,300,000

Amended MSKCC License [Member]

Collaboration agreement

Stock price appreciation milestones potential payments

75,000,000

Stock price appreciation milestone payable

$ 20,000,000

Enterprise Value Milestones Liability At Fair Value

$ 1,300,000

$ 3,900,000

Collaboration and License Agr_4

Collaboration and License Agreements (Details 1) - Amended MSK License $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) $ / shares
Milestone One
Collaboration agreement
Common stock multiple	5.0x
Ten-trading day trailing average common stock price | $ / shares	$ 50.18
Stock price appreciation milestone payment | $	$ 20
Milestone Two
Collaboration agreement
Common stock multiple	10.0x
Ten-trading day trailing average common stock price | $ / shares	$ 100.36
Stock price appreciation milestone payment | $	$ 30
Milestone Three
Collaboration agreement
Common stock multiple	15.0x
Ten-trading day trailing average common stock price | $ / shares	$ 150.54
Stock price appreciation milestone payment | $	$ 25

Collaboration and License Agr_5

Collaboration and License Agreements (Details 2) - Amended MSK License - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Determine the estimated fair value of the enterprise value milestone payments
Risk-free interest rate	4%	4%
Expected volatility	84%	78.10%
Estimated term (in years)	15 years	16 years
Closing stock price as of measurement date	$ 3.74	$ 10.09

California Institute For Rege_2

California Institute For Regenerative Medicine Award (Details) - California Institute for Regenerative Medicine - FT516 $ in Millions	Apr. 05, 2018 USD ($)
Award from California institute for regenerative medicine
Award agreement executed date	Apr. 05, 2018
Award for first-in-human clinical trial	$ 4

Investments (Details)

Investments (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities, impairment			$ 0	$ 0	$ 0
Available-for-sale securities, realized gains (losses) on sales	$ 0	$ 0
Available-for-sale securities, recognition of expected credit losses	0	0
Prepaid Expenses And Other Assets
Schedule Of Available For Sale Securities [Line Items]
Accured Interest on investments	$ 900,000	$ 800,000
Treasuries, Commercial paper. Non US government securities and Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Short term investments, maturity start range		3 months
Short term investments, maturity end range		36 months

Investments (Details 2)

Investments (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Money market fund | Current Assets [Member]
Schedule Of Available For Sale Securities [Line Items]
Maturity (in years)	1 or less	1 or less
Amortized Cost	$ 35,273	$ 37,645
Unrealized Losses	0	0
Unrealized Gains	0	0
Estimated Fair Value	$ 35,273	$ 37,645
U.S. Treasury debt securities | Current Assets [Member]
Schedule Of Available For Sale Securities [Line Items]
Maturity (in years)	1 or less	1 or less
Amortized Cost	$ 82,811	$ 86,221
Unrealized Losses	(34)	(263)
Unrealized Gains	27	37
Estimated Fair Value	$ 82,804	$ 85,995
Non-U.S. government securities | Current Assets [Member]
Schedule Of Available For Sale Securities [Line Items]
Maturity (in years)	1 or less	1 or less
Amortized Cost	$ 999	$ 2,425
Unrealized Losses	0	(2)
Unrealized Gains	0	0
Estimated Fair Value	$ 999	$ 2,423
Municipal securities | Current Assets [Member]
Schedule Of Available For Sale Securities [Line Items]
Maturity (in years)	1 or less	1 or less
Amortized Cost	$ 5,000	$ 18,963
Unrealized Losses	(3)	(208)
Unrealized Gains	0	0
Estimated Fair Value	$ 4,997	$ 18,755
Municipal securities | Non-current Assets [Member]
Schedule Of Available For Sale Securities [Line Items]
Maturity (in years)		Greater than 1
Amortized Cost		$ 5,000
Unrealized Losses		(58)
Unrealized Gains		0
Estimated Fair Value		$ 4,942
Corporate debt securities | Current Assets [Member]
Schedule Of Available For Sale Securities [Line Items]
Maturity (in years)	1 or less	1 or less
Amortized Cost	$ 47,144	$ 126,691
Unrealized Losses	(51)	(1,138)
Unrealized Gains	14	5
Estimated Fair Value	$ 47,107	$ 125,558
Corporate debt securities | Non-current Assets [Member]
Schedule Of Available For Sale Securities [Line Items]
Maturity (in years)	Greater than 1
Amortized Cost	$ 977
Unrealized Losses	0
Unrealized Gains	3
Estimated Fair Value	$ 980
Commercial Paper | Current Assets [Member]
Schedule Of Available For Sale Securities [Line Items]
Maturity (in years)	1 or less	1 or less
Amortized Cost	$ 137,339	$ 152,056
Unrealized Losses	(62)	(230)
Unrealized Gains	121	4
Estimated Fair Value	137,398	151,830
Short-term Investments [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	308,566	424,001
Unrealized Losses	(150)	(1,841)
Unrealized Gains	162	46
Estimated Fair Value	308,578	422,206
Long-term Investments [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	977	5,000
Unrealized Losses	0	(58)
Unrealized Gains	3	0
Estimated Fair Value	$ 980	$ 4,942

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Quoted prices in Active Market for Identical Assets (Level 1) | Money market fund
Financial assets:
Money market fund	$ 35,273	$ 37,645
Quoted prices in Active Market for Identical Assets (Level 1) | U.S. Treasury debt securities
Financial assets:
Estimated Fair Value	82,804	85,995
Significant Other Observable Inputs (Level 2) | Non-U.S. government securities
Financial assets:
Estimated Fair Value	999	2,423
Significant Other Observable Inputs (Level 2) | Corporate debt securities
Financial assets:
Estimated Fair Value	48,087	125,558
Significant Other Observable Inputs (Level 2) | Municipal securities
Financial assets:
Estimated Fair Value	4,997	23,697
Significant Other Observable Inputs (Level 2) | Commercial Paper
Financial assets:
Estimated Fair Value	137,398	151,830
Fair Value Measurements Recurring
Financial assets:
Total assets measured at fair value on a recurring basis	309,558	427,148
Financial liabilities:
Total financial liabilities measured at fair value on a recurring basis	1,346	3,861
Fair Value Measurements Recurring | Stock price appreciation milestones
Financial liabilities:
Stock price appreciation milestones	1,346	3,861
Fair Value Measurements Recurring | Money market fund
Financial assets:
Money market fund	35,273	37,645
Fair Value Measurements Recurring | U.S. Treasury debt securities
Financial assets:
Estimated Fair Value	82,804	85,995
Fair Value Measurements Recurring | Non-U.S. government securities
Financial assets:
Estimated Fair Value	999	2,423
Fair Value Measurements Recurring | Corporate debt securities
Financial assets:
Estimated Fair Value	48,087	125,558
Fair Value Measurements Recurring | Municipal securities
Financial assets:
Estimated Fair Value	4,997	23,697
Fair Value Measurements Recurring | Commercial Paper
Financial assets:
Estimated Fair Value	137,398	151,830
Fair Value Measurements Recurring | Quoted prices in Active Market for Identical Assets (Level 1)
Financial assets:
Total assets measured at fair value on a recurring basis	118,077	123,640
Fair Value Measurements Recurring | Significant Other Observable Inputs (Level 2)
Financial assets:
Total assets measured at fair value on a recurring basis	191,481	303,508
Fair Value Measurements Recurring | Significant Unobservable Inputs (Level 3)
Financial assets:
Total assets measured at fair value on a recurring basis	0
Financial liabilities:
Total financial liabilities measured at fair value on a recurring basis	1,346	3,861
Fair Value Measurements Recurring | Significant Unobservable Inputs (Level 3) | Stock price appreciation milestones
Financial liabilities:
Stock price appreciation milestones	$ 1,346	$ 3,861

Fair Value Measurements (Deta_2

Fair Value Measurements (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Changes in fair value of stock price appreciation milestones liability	$ (2,515)	$ (20,307)
Fair Value, Assets, Level 1 to Level 2 Transfers, Amount	0
Fair Value, Assets, Level 2 to Level 1 Transfers, Amount	0
Fair Value, Liabilities, Level 1 to Level 2 Transfers, Amount	0
Fair Value, Liabilities, Level 2 to Level 1 Transfers, Amount	0
Fair Value Measurements Nonrecurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value on a recurring basis	0
Total financial liabilities measured at fair value on a recurring basis	$ 0

Fair Value Measurements (Deta_3

Fair Value Measurements (Details 3) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Changes in fair value of stock price appreciation milestones liability	$ (2,515)	$ (20,307)
Significant Unobservable Inputs (Level 3)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Balance at the beginning of the period	3,861	24,168
Changes in fair value of stock price appreciation milestones liability	(2,515)	(20,307)
Balance at the end of the period	$ 1,346	$ 3,861

Property and Equipment (Details

Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property and equipment
Property and equipment, gross	$ 144,462	$ 140,404
Less accumulated depreciation and amortization	(47,626)	(30,384)
Total property and equipment, net	96,836	110,020
Furniture And Fixtures
Property and equipment
Property and equipment, gross	1,309	1,209
Computer And Office Equipment
Property and equipment
Property and equipment, gross	3,132	2,937
Software
Property and equipment
Property and equipment, gross	2,130	2,122
Leasehold improvements-building
Property and equipment
Property and equipment, gross	59,038	56,782
Scientific Equipment
Property and equipment
Property and equipment, gross	$ 78,853	$ 77,354

Property and Equipment (Additio

Property and Equipment (Additional Information) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 18,282	$ 13,758

Accrued Expenses and Long-Ter_3

Accrued Expenses and Long-Term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current accrued expenses
Accrued payroll and other employee benefits	$ 10,563	$ 17,899
Accrued clinical trial related costs	8,833	16,858
Accrued other	8,118	19,175
Total current accrued expenses	$ 27,514	$ 53,932

Leases (Additional Information)

Leases (Additional Information) (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Jan. 31, 2020	Dec. 31, 2023 USD ($)	Apr. 30, 2023 ft²	Dec. 31, 2022 USD ($)
Lessee Lease Description [Line Items]
Right-of-use asset		$ 61,675		$ 66,069
Lessee, operating lease, option to extend		These leases have terms varying from one to approximately sixteen years, with renewal options of up to ten years
Net Rentable Area | ft²			18,913
Letters of credit outstanding amount		$ 15,200		$ 15,200
Future minimum payments under the operating leases		$ 162,928
Remaining weighted-average lease term		10 years 8 months 12 days
Operating lease liabilities, weighted-average discount rate		8.34%
The Premises 2020 Lease Agreement
Lessee Lease Description [Line Items]
Lessee, operating lease, existence of option to extend	true
Minimum
Lessee Lease Description [Line Items]
Future minimum payments under the operating leases		$ 162,900

Leases (Details 1)

Leases (Details 1) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Lease, Cost [Abstract]
Straight-line lease expense	$ 13,159	$ 15,010
Variable lease expense	2,250	2,614
Total operating lease expense	$ 15,409	$ 17,624

Leases (Details 2)

Leases (Details 2) $ in Thousands	Dec. 31, 2023 USD ($)
Lessee, Operating Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract]
2024	$ 14,659
2025	15,087
2026	15,540
2027	16,006
2028	15,057
Thereafter	86,579
Total undiscounted lease payments	162,928
Less: imputed interest	(59,392)
Total lease liability	$ 103,536

Schedule of sublease income - L

Schedule of sublease income - Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Sublease income	$ 729	$ 0

Convertible Preferred Stock a_3

Convertible Preferred Stock and Stockholders' Equity (Additional information) (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended			12 Months Ended
	Jun. 09, 2022	Apr. 30, 2023	Jan. 31, 2021	Nov. 30, 2016	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Mar. 31, 2020	Jan. 31, 2019	May 02, 2017	May 10, 2016
Convertible preferred stock
Preferred stock, par value (in dollars per share)					$ 0.001	$ 0.001
Shares reserved for issuance					36,044,714	38,846,873
Performance stock, granted							1,997,377
Issuance of common stock from equity incentive plans, net of issuance costs					$ 85	$ 9,207
Pre-Funded Warrants
Convertible preferred stock
Number of shares to be purchased			257,310		257,310
Purchase price of prefunded warrants			$ 85.499
Exercise price of warrants			$ 0.001
Terms of exercise			The Pre-Funded Warrants are exercisable at any time after the date of issuance. A holder of Pre-Funded Warrants may not exercise the Pre-Funded Warrant if the holder, together with its affiliates, would beneficially own more than 9.99% of the number of shares of the Company’s common stock outstanding immediately after giving effect to such exercise. A holder of Pre-Funded Warrants may increase or decrease this percentage not in excess of 19.99% by providing at least 61 days’ prior notice to the Company.
Maximum percentage of common stock ownership together with affiliates allowable after exercise of prefunded warrants			9.99%
Maximum percentage of common stock ownership after change upon notice.			19.99%
Employee and Non Employee Stock Option
Convertible preferred stock
Weighted-average grant date fair value per share of employee options granted					$ 4.83	$ 24.07
Total intrinsic value of stock options exercised					$ 300	$ 23,800
Issuance of common stock from equity incentive plans, net of issuance costs					$ 300
Employee Stock Purchase Plan
Convertible preferred stock
Shares reserved for issuance					0	729,000
Restricted Stock Units (RSUs)
Convertible preferred stock
Shares reserved for issuance					3,065,087	5,862,733
Expected recognition period of unrecognized compensation cost					2 years	2 years 9 months 18 days
Performance stock, granted					1,161,540
Unrecognized compensation cost related to unvested restricted shares					$ 38,300	$ 137,700
Performance-based restricted granted, none of vested Units Outstanding					1,020,617	1,797,619
Common Stock
Convertible preferred stock
Conversion of preferred shares to common stock		167,205
Non-Voting Class A Preferred Stock | Maximum
Convertible preferred stock
Number of shares to be issued upon conversion										14,097,745
Non-Voting Class A Preferred Stock | Redmile Group, LLC and Affiliates
Convertible preferred stock
Percentage of common stock ownership upon preferred stock conversion				19.99%
Terms of conversion					The Class A Preferred were purchased exclusively by entities affiliated with Redmile Group, LLC (collectively, Redmile). The terms of the CoD prohibited Redmile from converting the Class A Preferred into shares of the Company’s common stock if, as a result of conversion, Redmile, together with its affiliates, would own more than 9.99% of the Company’s common stock then issued and outstanding (the Redmile Percentage Limitation), which percentage could change at Redmile’s election upon 61 days’ notice to the Company to (i) any other number less than or equal to 19.99% or (ii) subject to approval of the Company’s stockholders to the extent required in accordance with the NASDAQ Global Market rules, any number in excess of 19.99%. On May 2, 2017, the Company’s stockholders approved the issuance of up to an aggregate of 14,097,745 shares of common stock upon the conversion of the outstanding shares of Class A Preferred. As a result, Redmile has the right to increase the Redmile Percentage Limitation to any percentage in excess of 19.99% at its election.
Non-Voting Class A Preferred Stock | Redmile Group, LLC and Affiliates | Maximum
Convertible preferred stock
Percentage of common stock ownership upon preferred stock conversion				9.99%
Preferred shares converted into common stock percentage of ownership change upon notice				19.99%
Class A Convertible Preferred Shares
Convertible preferred stock
Preferred stock, issued shares					2,761,108	2,794,549
Percentage of common stock ownership upon preferred stock conversion		14.99%
Conversion of preferred shares to common stock		33,441
Class A Convertible Preferred Shares | Redmile Group, LLC and Affiliates
Convertible preferred stock
Percentage of common stock ownership upon preferred stock conversion				19.99%
Stock Option And Incentive Plan 2013 | Employee and Non Employee Stock Option
Convertible preferred stock
Unrecognized compensation cost related to outstanding options					$ 23,000	$ 35,100
Expected recognition period of unrecognized compensation cost					1 year 10 months 24 days	2 years 2 months 12 days
Stock Option And Incentive Plan2022 [Member]
Convertible preferred stock
Common stock issued	9,500,000
Shares reserved for issuance					8,633,496	10,274,169
Stock Option And Incentive Plan2022 [Member] | Employee and Non Employee Stock Option
Convertible preferred stock
Stock options generally vested on anniversary grant date (as a percent)	25%
General vesting period after first year	3 years
Monthly vesting period	4 years
Term of stock awards	10 years
Stock Option And Incentive Plan2022 [Member] | Restricted Stock Units (RSUs)
Convertible preferred stock
Annually vesting period	4 years
Inducement Plan
Convertible preferred stock
Shares reserved for issuance					689,750	741,000					500,000
Additional shares reserved for issuance			300,000					470,822	200,000
November 2016 Placement | Common Stock
Convertible preferred stock
Common stock issued				7,236,837
Share issue price (in dollars per share)				$ 2.66
November 2016 Placement | Non-Voting Class A Preferred Stock
Convertible preferred stock
Preferred stock, issued shares				2,819,549
Share issue price (in dollars per share)				$ 13.3
Preferred stock, par value (in dollars per share)				0.001
Conversion price				$ 2.66

Convertible Preferred Stock a_4

Convertible Preferred Stock and Stockholders' Equity - Stock option activity under all equity and stock option plans (Details) - Employee and Non Employee Stock Option $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) $ / shares shares
Number of Options
Balance at the beginning of the period | shares	7,267,226
Granted | shares	5,875,000
Exercised | shares	(93,787)
Cancelled | shares	(3,197,598)
Balance at the end of the period | shares	9,850,841
Vested and expected to vest at the end of the period | shares	9,850,841
Exercisable at the end of the period | shares	6,297,349
Weighted-Average Price
Balance at the beginning of the period | $ / shares	$ 22.37
Granted | $ / shares	6.39
Exercised | $ / shares	3.24
Cancelled | $ / shares	20.26
Balance at the end of the period | $ / shares	13.71
Vested and expected to vest at the end of the period | $ / shares	13.71
Exercisable at the end of the period | $ / shares	$ 15.81
Weighted Average Remaining Contractual Term
Outstanding at the end of the period	6 years 9 months 29 days
Vested and expected to vest at the end of the period	6 years 9 months 29 days
Exercisable at the end of the period	5 years 6 months 21 days
Aggregate Intrinsic Value
Outstanding at the end of the period | $	$ 903
Vested and expected to vest at the end of the period | $	903
Exercisable at the end of the period | $	$ 392

Convertible Preferred Stock a_5

Convertible Preferred Stock and Stockholders' Equity - Restricted stock unit activity under all equity and stock option plans (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2021
Number of Restricted Stock Units
Granted		1,997,377
Restricted Stock Units (RSUs)
Number of Restricted Stock Units
Balance at the beginning of the period	5,862,733
Granted	1,161,540
Vested	(1,071,167)
Cancelled	(2,888,019)
Balance at the end of the period	3,065,087
Expected to vest at the end of the period	2,044,470
Weighted-Average Grant Date Fair Value per Share
Balance at the beginning of the period	$ 48.13
Granted	6.68
Vested	42.71
Cancelled	44.12
Balance at the end of the period	37.96
Expected to vest at the end of the period	$ 28.74
Weighted Average Remaining Vesting Period
Outstanding at the end of the period	2 years 7 months 2 days
Expected to vest at the end of the period	2 years 4 months 17 days
Aggregate Intrinsic Value
Outstanding at the end of the period (in dollars)	$ 11,463
Restricted stock units expected to vest at December 31, 2021	$ 7,646

Convertible Preferred Stock a_6

Convertible Preferred Stock and Stockholders' Equity - Stock based compensation for all stock awards (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Convertible preferred stock
Total stock-based compensation expense	$ 43,459	$ 78,733
Research And Development
Convertible preferred stock
Total stock-based compensation expense	20,849	51,103
General And Administrative
Convertible preferred stock
Total stock-based compensation expense	$ 22,610	$ 27,630

Convertible Preferred Stock a_7

Convertible Preferred Stock and Stockholders' Equity - Weighted average assumptions used in the Black-Scholes option pricing model (Details) - Employee and Non Employee Stock Option	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Weighted-average assumptions to determine fair value of stock options
Risk–free interest rate	3.80%	1.90%
Expected volatility	89.30%	76.20%
Expected term (in years)	6 years 6 months	5 years 9 months 18 days
Expected dividend yield	0%	0%

Convertible Preferred Stock a_8

Convertible Preferred Stock and Stockholders' Equity (Details 6) - shares	Dec. 31, 2023	Dec. 31, 2022	May 10, 2016
Weighted-average assumptions to determine fair value of stock options
Shares reserved for issuance	36,044,714	38,846,873
Awards available under the 2022 Plan
Weighted-average assumptions to determine fair value of stock options
Shares reserved for issuance	8,633,496	10,274,169
Inducement Plan
Weighted-average assumptions to determine fair value of stock options
Shares reserved for issuance	689,750	741,000	500,000
Employee Stock Option
Weighted-average assumptions to determine fair value of stock options
Shares reserved for issuance	9,850,841	7,267,226
Restricted Stock Units (RSUs)
Weighted-average assumptions to determine fair value of stock options
Shares reserved for issuance	3,065,087	5,862,733
Employee Stock Purchase Plan
Weighted-average assumptions to determine fair value of stock options
Shares reserved for issuance	0	729,000
Convertible Preferred Stock (if converted)
Weighted-average assumptions to determine fair value of stock options
Shares reserved for issuance	13,805,540	13,972,745

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Reconciliation of the Company's expected federal income tax provision (benefit) to the actual income tax provision
Tax computed at federal statutory rate	$ (33,794)	$ (59,161)
State tax, net of federal tax benefit	(4,851)	(11,109)
Non-deductible compensation	25	2,086
Permanent differences	(2,305)	(1,340)
Stock compensation	12,801	3,356
R&D tax credits	(5,773)	(14,484)
Reserve for uncertain tax positions	4,254	12,564
Other	1,928	(1,376)
Valuation allowance	27,715	69,464
Income tax expense	0	0
Deferred tax assets:
Capitalized R&D expense	134,209	127,250
Net operating losses	112,810	84,608
R&D tax credits	55,492	49,736
Intangible asset amortization	9,220	8,012
Deferred revenue	144	8,714
Stock compensation	8,322	13,128
Lease liability	21,761	22,961
Other	672	2,526
Total deferred tax assets	342,630	316,935
Deferred tax liabilities:
Depreciation	(5,639)	(6,814)
Right-of-use assets	(13,029)	(13,874)
Total deferred tax liabilities	(18,668)	(20,688)
Net of deferred tax assets and liabilities	323,962	296,247
Valuation allowance	(323,962)	(296,247)
Net deferred tax assets	$ 0	$ 0

Income Taxes (Details 2)

Income Taxes (Details 2) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating Loss Carryforwards [Line Items]
Valuation allowance	$ 323,962,000	$ 296,247,000
U.S. Federal
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 526,400,000
Net operating loss carryforward expiration year	2027
California
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 522,100
Net operating loss carryforward expiration year	2028

Income Taxes (Details 3)

Income Taxes (Details 3) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($)
Tax Credit Carryforward [Line Items]
Cumulative changes in ownership percentage	50%
Period of change in ownership	3 years
Californian
Tax Credit Carryforward [Line Items]
Income tax examination, year under examination	2019
U.S. Federal
Tax Credit Carryforward [Line Items]
Income tax examination, year under examination	2020
U.S. Federal | Research and development
Tax Credit Carryforward [Line Items]
Tax credit carryforwards	$ 40.3
Tax credit carryforward expiration year	2035
California
Tax Credit Carryforward [Line Items]
Tax credit carryforwards	$ 34.7

Income Taxes (Details 4)

Income Taxes (Details 4) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Change in the Company's unrecognized tax benefits
Beginning unrecognized tax benefits	$ 52,767,000	$ 37,255,000
Increase related to current year tax positions	9,724,000	9,101,000
Increase related to prior year tax positions	90,000	6,411,000
Decrease related to prior year tax positions	(2,901,000)	0
Ending unrecognized tax benefits	59,680,000	$ 52,767,000
Income Taxes
Unrecognized tax benefit	0
Unrecognized tax benefits that, if recognized, would reduce the effective tax rate	$ 0

Employee Benefits (Details)

Employee Benefits (Details) - USD ($) $ in Millions		12 Months Ended
	Jan. 01, 2009	Dec. 31, 2023	Dec. 31, 2022
Retirement Benefits [Abstract]
Minimum age of employees	21 years
Percentage of discretionary contributions description		The Company makes discretionary contributions to the 401(k) Plan equal to 100 percent of each employee’s pretax contributions up to 20 percent of the IRS Standard Limit.
Total Company's Contributions		$ 1.9	$ 1.3

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Minimum annual payments to maintain licenses	$ 0.4

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ in Thousands		12 Months Ended
	Feb. 22, 2024	Dec. 31, 2023
Subsequent Event [Line Items]
Stock awarded grant value		$ 1
Subsequent Event | California Institute for Regenerative Medicine
Subsequent Event [Line Items]
Grant awarded	$ 7,900