Fate Therapeutics (FATE) 10-Q 3 May 23 2023 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2023	Apr. 27, 2023
Cover [Abstract]
Entity Registrant Name	FATE THERAPEUTICS, INC.
Entity Central Index Key	0001434316
Document Type	10-Q
Document Period End Date	Mar. 31, 2023
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Trading Symbol	FATE
Entity Common Stock, Shares Outstanding		98,384,456
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q1
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity File Number	001-36076
Entity Tax Identification Number	65-1311552
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
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Document Transition Report	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 42,020	$ 61,333
Accounts receivable	13,500	38,480
Short-term investments and related maturity receivables	366,878	374,894
Prepaid expenses and other current assets	15,490	27,367
Total current assets	437,888	502,074
Long-term investments	3,912	4,942
Property and equipment, net	108,594	110,020
Operating lease right-of-use assets	64,682	66,069
Restricted cash	15,227	15,227
Collaboration contract asset	0	7,196
Other assets	33	33
Total assets	630,336	705,561
Current liabilities:
Accounts payable	9,855	8,265
Accrued expenses	31,513	53,932
CIRM award liability, current portion	0	4,000
Deferred revenue, current portion	1,738	42,226
Operating lease liabilities, current portion	5,545	5,628
Total current liabilities	48,651	114,051
Operating lease liabilities, net of current portion	102,070	103,710
Stock price appreciation milestones	2,143	3,861
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.001 par value; authorized shares-5,000,000 at March 31, 2023 and December 31, 2022;class A Convertible Preferred shares issued and outstanding -2,794,549 at March 31,2023 and December 31,2022	3	3
Common stock, $0.001 par value; authorized shares-250,000,000 at March 31, 2023 and December 31, 2022; issued and outstanding 98,191,015at March 31, 2023 and 97,294,917 at December 31, 2022	98	97
Additional paid-in capital	1,547,702	1,536,497
Accumulated other comprehensive loss	(646)	(1,854)
Accumulated deficit	(1,069,685)	(1,050,804)
Total stockholders’ equity	477,472	483,939
Total liabilities and stockholders’ equity	$ 630,336	$ 705,561

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 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	98,191,015	97,294,917
Common stock, outstanding shares	98,191,015	97,294,917
Class A Convertible Preferred Shares
Preferred stock, issued shares	2,794,549	2,794,549
Preferred stock, outstanding shares	2,794,549	2,794,549

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Income Statement [Abstract]
Collaboration revenue	$ 58,980	$ 18,414
Type of Revenue [Extensible List]	us-gaap:LicenseMember	us-gaap:LicenseMember
Operating expenses:
Research and development	$ 65,629	$ 72,139
General and administrative	21,943	20,742
Total operating expenses	87,572	92,881
Loss from operations	(28,592)	(74,467)
Other income:
Interest income	3,694	418
Change in fair value of stock price appreciation milestones	1,718	8,359
Other income:	4,299	0
Total other income	9,711	8,777
Net loss	(18,881)	(65,690)
Other comprehensive income (loss):
Unrealized gain (loss) on available-for-sale securities, net	1,208	(2,088)
Comprehensive loss	$ (17,673)	$ (67,778)
Earnings Per Share, Basic	$ (0.19)	$ (0.68)
Earnings Per Share, Diluted	$ (0.19)	$ (0.68)
Weighted Average Number of Shares Outstanding, Basic	98,054,687	96,343,529
Weighted Average Number of Shares Outstanding, Diluted	98,054,687	96,343,529

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Operating activities
Net loss	$ (18,881)	$ (65,690)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	4,191	2,761
Stock-based compensation	10,983	19,331
Accretion and amortization of premiums and discounts on investments, net	(2,295)	873
Amortization of collaboration contract assets	7,196	1,094
Deferred revenue	(40,488)	(3,497)
Change in fair value of stock price appreciation milestones	(1,718)	(8,359)
Changes in operating assets and liabilities:
Grant income from CIRM award	(4,000)	0
Accounts receivable	24,980	(5,174)
Prepaid expenses and other assets	11,901	(2,407)
Accounts payable and accrued expenses	(20,393)	(3,493)
Right-of-use assets and lease liabilities, net	(336)	(52)
Net cash used in operating activities	(28,860)	(64,613)
Investing activities
Purchases of property and equipment	(3,208)	(10,084)
Purchases of investments	(114,452)	(132,166)
Maturities of investments	127,000	135,224
Net cash provided by (used in) investing activities	9,340	(7,026)
Financing activities
Issuance of common stock from equity incentive plans, net of issuance costs	207	2,797
Net cash provided by financing activities	207	2,797
Net change in cash, cash equivalents and restricted cash	(19,313)	(68,842)
Cash, cash equivalents and restricted cash at beginning of the period	76,560	148,810
Cash, cash equivalents and restricted cash at end of the period	57,247	79,968
Supplemental schedule of noncash investing and financing activities
Purchases of property and equipment in accounts payable	$ 612	$ 3,377

Organization and Summary of Sig

Organization and Summary of Significant Accounting Policies	3 Months Ended
	Mar. 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 natural killer (NK) and T-cell product candidates to patients for the treatment of cancer and autoimmune disease. As of March 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. 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 %, to approximately 220 employees. 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 three months ended March 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. As of March 31, 2023, all restructuring and related expenses have been fully recognized by the Company. The Company also evaluated the impact of the restructuring on the carrying value of its long-lived assets, such as property and equipment and operating lease assets. This process included evaluating the estimated remaining lives, significant changes in the use, and potential impairment charges related to its long-lived assets. Based on its evaluation, the Company determined that its long-lived assets were not impaired as of March 31, 2023, and it has not recognized any impairment charges related to its long-lived assets since the restructuring announcement. Use of Estimates The Company’s unaudited condensed consolidated financial statements are prepared in accordance with United States generally accepted accounting principles (U.S. GAAP). The preparation of the Company’s unaudited condensed consolidated financial statements requires management 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 unaudited condensed consolidated financial statements and accompanying notes. The most significant estimates and assumptions in the Company’s unaudited condensed consolidated financial statements relate to its stock price 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 unaudited condensed 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. Cash, Cash Equivalents and Restricted Cash Cash and cash equivalents include cash in readily available operating 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 unaudited condensed consolidated balance sheets that sum to the total of the same such amounts shown in the unaudited condensed consolidated statements of cash flows as of March 31, 2023 and 2022 (in thousands): Three Months Ended March 31, 2023 2022 Cash and cash equivalents $ 42,020 $ 64,741 Restricted cash 15,227 15,227 Total cash, cash equivalents, and restricted cash shown in the unaudited condensed consolidated statement of cash flows $ 57,247 $ 79,968 For each of the three months ended March 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 unaudited condensed 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 unaudited condensed 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 unaudited condensed 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. Unaudited Interim Financial Information The accompanying interim condensed consolidated financial statements are unaudited. These unaudited interim condensed consolidated financial statements have been prepared in accordance with U.S. GAAP and following the requirements of the United States Securities and Exchange Commission (SEC) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required can be condensed or omitted. The interim unaudited condensed consolidated financial statements should be read in conjunction with the Company’s financial statements and accompanying notes for the fiscal year ended December 31, 2022, contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022, filed by the Company with the SEC on February 28, 2023. In management’s opinion, the unaudited interim condensed consolidated financial statements have been prepared on the same basis as the audited financial statements and include all adjustments, which include only normal recurring adjustments, necessary for the fair presentation of the Company’s financial position and its results of operations and comprehensive loss and its cash flows for the periods presented. The results for the three months ended March 31, 2023 are not necessarily indicative of the results expected for the full fiscal year or any other interim period or any future year or period. 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. The Company considers the terms of a contract and all relevant facts and circumstances when applying the revenue recognition standard. The Company applies the revenue recognition standard, including the use of any practical expedients, consistently to contracts with similar characteristics and in similar circumstances. A customer is a party that has entered into a contract with the Company, where the purpose of the contract is to obtain a product or a service that is an output of the Company’s ordinary activities in exchange for consideration. To be considered a contract, (i) the contract must be approved (in writing, orally, or in accordance with other customary business practices), (ii) each party’s rights regarding the product or the service to be transferred can be identified, (iii) the payment terms for the product or the service to be transferred can be identified, (iv) the contract must have commercial substance (that is, the risk, timing or amount of future cash flows is expected to change as a result of the contract), and (v) it is probable that the Company will collect substantially all of the consideration to which it is entitled to receive in exchange for the transfer of the product or the service. A performance obligation is defined as a promise to transfer a product or a service to a customer. The Company identifies each promise to transfer a product or a service (or a bundle of products or services, or a series of products and services that are substantially the same and have the same pattern of transfer) that is distinct. A product or a service is distinct if both (i) the customer can benefit from the product or the service either on its own or together with other resources that are readily available to the customer and (ii) the Company’s promise to transfer the product or the service to the customer is separately identifiable from other promises in the contract. Each distinct promise to transfer a product or a service is a unit of accounting for revenue recognition. If a promise to transfer a product or a service is not separately identifiable from other promises in the contract, such promises should be combined into a single performance obligation. The transaction price is the amount of consideration the Company is entitled to receive in exchange for the transfer of control of a product or a service to a customer. To determine the transaction price, the Company considers the existence of any significant financing component, the effects of any variable elements, noncash considerations and consideration payable to the customer. If a significant financing component exists, the transaction price is adjusted for the time value of money. If an element of variability exists, the Company must estimate the consideration it expects to receive and uses that amount as the basis for recognizing revenue as the product or the service is transferred to the customer. There are two methods for determining the amount of variable consideration: (i) the expected value method, which is the sum of probability-weighted amounts in a range of possible consideration amounts, and (ii) the mostly likely amount method, which identifies the single most likely amount in a range of possible consideration amounts. If a contract has multiple performance obligations, the Company allocates the transaction price to each distinct performance obligation in an amount that reflects the consideration the Company is entitled to receive in exchange for satisfying each distinct performance obligation. For each distinct performance obligation, revenue is recognized when (or as) the Company transfers control of the product or the service applicable to such performance obligation. In those instances where the Company first receives consideration in advance of satisfying its performance obligation, the Company classifies such consideration as deferred revenue until (or as) the Company satisfies such performance obligation. In those instances where the Company first satisfies its performance obligation prior to its receipt of consideration, the consideration is recorded as accounts receivable. The Company expenses incremental costs of obtaining and fulfilling a contract as and when incurred if the expected amortization period of the asset that would be recognized is one year or less, or if the amount of the asset is immaterial. Otherwise, such costs are capitalized as contract assets if they are incremental to the contract and amortized to expense proportionate to revenue recognition of the underlying contract. 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, 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 unaudited condensed consolidated statements of operations and comprehensive loss. 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 unaudited condensed 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. 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 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. Convertible Preferred Stock The Company applies the relevant accounting standards to distinguish liabilities from equity when assessing the classification and measurement of preferred stock. Preferred shares subject to mandatory redemptions are considered liabilities and measured at fair value. Conditionally redeemable preferred shares are considered temporary equity. All other preferred shares are considered as stockholders’ equity. The Company applies the relevant accounting standards for derivatives and hedging (in addition to distinguishing liabilities from equity) when accounting for hybrid contracts that contain conversion options. Conversion options must be bifurcated from the host instruments and accounted for as free-standing financial instruments according to certain criteria. These criteria include circumstances when (i) the economic characteristics and risks of the embedded derivative instruments are not clearly and closely related to the economic characteristics and risks of the host contract, (ii) the hybrid instrument that embodies both the embedded derivative instrument and the host contract is not re-measured at fair value under otherwise applicable accounting principles with changes in fair value reported in earnings as they occurred, and (iii) a separate instrument with the same terms as the embedded derivative instrument would be considered a derivative instrument. The derivative is subsequently measured at fair value at each reporting date, with the changes in fair value reported in earnings. 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, other than losses attributable to a credit loss which are included in other income and expense, on investments classified as available-for-sale securities, which was the only difference between net loss and comprehensive loss for the applicable periods. Net Loss Per Common Share Basic net loss per common share is calculated by dividing the net loss by the weighted-average number of shares of common stock outstanding for the period, without consideration for common stock equivalents. The Pre-Funded Warrants associated with the January 2021 public equity offering (see Note 8) are considered outstanding shares in the basic earnings per share calculation given their nominal exercise price. Dilutive common stock equivalents for the periods presented include 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 and incentive plans. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding due to the Company’s net loss position. For the three months ended March 31, 2023 , the Company realized a net loss of $ 18.9 million. Shares of potentially dilutive securities totaled 29.8 million for the three months ended March 31, 2023 , including 14.0 million shares associated with a hypothetical conversion of all outstanding shares of the Company’s Class A convertible preferred stock, and an aggregate of 15.8 million shares of common stock issuable upon the exercise of outstanding stock options and the vesting of outstanding restricted stock units. For the three months ended March 31, 2022 , the Company realized a net loss of $ 65.7 million. Shares of potentially dilutive securities totaled 27.7 million for the three months ended March 31, 2022 , including 14.0 million shares associated with a hypothetical conversion of all outstanding shares of the Company’s Class A convertible preferred stock, and an aggregate of 13.7 million shares of common stock issuable upon the exercise of outstanding stock options and the vesting of outstanding restricted stock units. 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.

Collaboration and License Agree

Collaboration and License Agreements	3 Months Ended
	Mar. 31, 2023
Collaboration And License Agreements Disclosure [Abstract]
Collaboration and License Agreements	2. Collaboration and License Agreements 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). 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. Additionally, the Company was entitled to receive full funding for the conduct of all research, preclinical development and IND-enabling activities performed by the Company under the Janssen Agreement. 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. 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 expects to be reimbursed for all wind down activities in the second quarter of this year. In connection with the termination, and per the terms of the Janssen Agreement, (i) all licenses and other rights granted to either party pursuant to the Janssen Agreement have terminated, subject to limited exceptions set forth in the Janssen Agreement; (ii) both parties have wound down all development, commercialization and manufacturing activities under the Janssen Agreement; (iii) neither party has any right to continue to develop, manufacture or commercialize any collaboration candidate or collaboration product or use the other party’s materials; and (iv) neither party is restricted from independently developing, manufacturing, or commercializing any product, including any products directed to the same antigens as those of any collaboration candidate or collaboration product. In connection with the Janssen Agreement, the Company has incurred $ 17.1 million in sublicense fees to certain of its existing licensors as of March 31, 2023. The $ 17.1 million in sublicense consideration represents an asset under ASC Topic 340, Other Assets and Deferred Costs (ASC 340) and was amortized to research and development expense ratably with the Company’s revenue recognition under the Janssen Agreement. During the three months ended March 31, 2023 and 2022 , the Company recognized $ 7.2 million and $ 1.1 million of such expense, respectively. As of March 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 three months ended March 31, 2023 , of which $ 41.2 million was previously deferred. Such revenue comprised $ 11.1 million associated with research and development services, $ 31.2 million associated with the upfront fee and Equity Premium, and $ 10.0 million associated with a commercial option exercise for the three months ended March 31, 2023 . The Company recognized revenue of $ 15.9 million for the three months ended March 31, 2022 . Such revenue comprised $ 9.8 million associated with research and development services and $ 6.1 million associated with the upfront fee and Equity Premium for the three months ended March 31, 2022. As of March 31, 2023 , the Company has received $ 82.0 million in aggregate research and development fees from Janssen. Ono Collaboration and Option Agreement On September 14, 2018, the Company entered into a Collaboration and Option Agreement (the Ono Agreement) with 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 Ono Amendment). Pursuant to the 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 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. Under the terms of the Ono Agreement (as amended by the 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 such 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 Amendment 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 Amendment 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, which is estimated to be four years . 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 Ono Amendment equals $ 39.3 million, consisting of the upfront, non-refundable and non-creditable payment of $ 10.0 million and the aggregate estimated research and development fees of $ 29.3 million. The upfront payment of $ 10.0 million was recorded as deferred revenue and is being 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 will be 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. 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 three months ended March 31, 2023 , the Company recognized contra-research and development expense of $ 1.0 million. As of March 31, 2023, there were no cost-sharing payments made to the Company from Ono. 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 as of March 31, 2023 . The $ 7.8 million in sublicense consideration represents an asset under ASC 340 and was amortized to research and development expense ratably with the Company’s revenue recognition under the Ono Agreement. During the three months ended March 31, 2023, the Company recognized none of such expense, and during the three months ended March 31, 2022 , the Company recognized $ 0.3 million of such expense. The Company recognized revenue of $ 6.7 million under the Ono Agreement for the three months ended March 31, 2023. All of such revenue was associated with research services for the three months ended March 31, 2023. During the three months ended March 31, 2022 , the Company recognized revenue of $ 2.5 million under the Ono Agreement. Such revenue comprised $ 1.2 million associated with research services and $ 1.3 million associated with the upfront payment for the three months ended March 31, 2022. As of March 31, 2023 , the Company has received $ 29.2 million in aggregate research and development fees from Ono. Memorial Sloan Kettering Cancer Center License Agreement On May 15, 2018, the Company entered into an Amended and Restated Exclusive License Agreement (Amended MSK License) with Memorial Sloan Kettering Cancer Center (MSK). The Amended MSK License amends and restates the Exclusive License Agreement entered into between the Company and MSK on August 19, 2016 (Original MSK License), pursuant to which the Company entered into an exclusive license agreement with MSK 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 MSK License, MSK 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 MSK License, in which case it is obligated to pay MSK a percentage of certain sublicense income received by the Company. The Company is obligated to pay to MSK an annual license maintenance fee during the term of the agreement, and is required to make 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, MSK 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 MSK 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 MSK License, adjusted for any stock splits, cash dividends, stock dividends, other distributions, combinations, recapitalizations, or similar events. Under the terms of the Amended MSK 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 MSK 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 MSK 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 MSK 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 March 31, 2023: As of March 31, As of December 31, 2023 2022 Risk-free interest rate 3.6 % 4.0 % Expected volatility 83.9 % 78.1 % Estimated term (in years) 15.8 16.0 Closing stock price as of remeasurement date $ 5.70 $ 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 unaudited condensed 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 three months ended March 31, 2023 , the Company recorded $ 1.7 million of income associated with the change in fair value of the stock price appreciation milestones. As of March 31, 2023 , the Company recorded a liability of $ 2.1 million associated with the stock price appreciation milestones for the Amended MSK License.

California Institute for Regene

California Institute for Regenerative Medicine Award	3 Months Ended
	Mar. 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. In connection with the Company's decision to discontinue its FT516 program during the first quarter of 2023, the Company reversed the liability associated with the Award and recorded such amount in other income during the three months ended March 31, 2023.

Investments

Investments	3 Months Ended
	Mar. 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 March 31, 2023 and December 31, 2022 (in thousands, except for maturity in years): Maturity Amortized Unrealized Unrealized Estimated March 31, 2023 Classified as current assets: U.S. Treasury debt securities 1 or less $ 108,628 $ ( 42 ) $ 105 $ 108,691 Non-U.S. government securities 1 or less 2,452 ( 6 ) — 2,446 Municipal securities 1 or less 14,978 ( 118 ) — 14,860 Corporate debt securities 1 or less 102,936 ( 427 ) 7 102,516 Commercial paper 1 or less 138,559 ( 194 ) — 138,365 Total short-term investments $ 367,553 $ ( 787 ) $ 112 $ 366,878 Classified as non-current assets: U.S. Treasury debt securities Greater than 1 $ 3,883 $ — $ 29 $ 3,912 Total long-term investments $ 3,883 $ — $ 29 $ 3,912 December 31, 2022 Classified as current assets: U.S. Treasury debt securities 1 or less $ 79,251 $ ( 263 ) $ 37 $ 79,025 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 123,996 ( 1,138 ) 3 122,861 Commercial paper 1 or less 152,056 ( 230 ) 4 151,830 Total short-term investments $ 376,691 $ ( 1,841 ) $ 44 $ 374,894 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 March 31, 2023 and December 31, 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 unaudited condensed consolidated balance sheets. The following tables present gross unrealized losses and fair values for those investments that were in an unrealized loss position as of March 31, 2023 and December 31, 2022, aggregated by investment category and the length of time that individual securities have been in a continuous loss position (in thousands): Less Than 12 Months 12 Months or Greater Total Estimated Fair Value Unrealized Losses Estimated Fair Value Unrealized Losses Estimated Fair Value Unrealized Losses March 31, 2023 U.S. Treasury debt securities $ 37,607 $ ( 42 ) $ — $ — $ 37,607 $ ( 42 ) Non-U.S. government securities 2,446 ( 6 ) — — 2,446 ( 6 ) Municipal securities 4,957 ( 43 ) 9,904 ( 75 ) 14,861 ( 118 ) Corporate debt securities 34,111 ( 111 ) 63,108 ( 316 ) 97,219 ( 427 ) Commercial paper 84,621 ( 194 ) — — 84,621 ( 194 ) Total $ 163,742 $ ( 396 ) $ 73,012 $ ( 391 ) $ 236,754 $ ( 787 ) December 31, 2022 U.S. Treasury debt securities $ 51,246 $ ( 163 ) $ 9,898 $ ( 100 ) $ 61,144 $ ( 263 ) Non-U.S. government securities 2,424 ( 2 ) — — 2,424 ( 2 ) Municipal securities 14,765 ( 193 ) 8,933 ( 73 ) 23,698 ( 266 ) Corporate debt securities 45,621 ( 174 ) 71,625 ( 964 ) 117,246 ( 1,138 ) Commercial paper 66,455 ( 230 ) — — 66,455 ( 230 ) Total $ 180,511 $ ( 762 ) $ 90,456 $ ( 1,137 ) $ 270,967 $ ( 1,899 ) 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 each of the three months ended March 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 no t record an allowance for, or recognize, any expected credit losses.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurements	5. Fair Value Measurements 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. Changes in the ability to observe valuation inputs may result in reclassification of levels for certain securities within the fair value hierarchy. The following table presents the Company’s financial assets and liabilities measured at fair value on a recurring basis as of March 31, 2023 and December 31, 2022 (in thousands): Fair Value Measurements at Total Quoted Prices Significant Significant As of March 31, 2023 Financial assets: Money market funds $ 42,020 $ 42,020 $ — $ — U.S. Treasury debt securities 112,603 112,603 — — Non-U.S. government securities 2,446 — 2,446 — Municipal securities 14,860 — 14,860 — Corporate debt securities 102,516 — 102,516 — Commercial paper 138,365 — 138,365 — Total financial assets measured at fair value on a recurring basis $ 412,810 $ 154,623 $ 258,187 $ — Financial liabilities: Stock price appreciation milestones $ 2,143 $ — $ — $ 2,143 Total financial liabilities measured at fair value on a recurring basis $ 2,143 $ — $ — $ 2,143 As of December 31, 2022 Financial assets: Money market funds $ 61,333 $ 61,333 $ — $ — U.S. Treasury debt securities 79,025 79,025 — — Non-U.S. government securities 2,423 — 2,423 — Municipal securities 23,697 — 23,697 — Corporate debt securities 122,861 — 122,861 — Commercial paper 151,830 — 151,830 — Total assets measured at fair value on a recurring basis $ 441,169 $ 140,358 $ 300,811 $ — 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 March 31, 2023. Level 3 liabilities consisted of stock price appreciation milestones associated with the Amended MSK License as described in detail in Note 2. To determine the estimated fair value of the stock price appreciation milestones, the Company uses a Monte Carlo simulation methodology which models future Company common stock prices based on several key variables. The assumptions used to calculate the fair value of the stock price appreciation milestones are subject to a significant amount of judgment including the expected volatility of the Company’s common stock and estimated term, which is based in part on the last valid patent claim date. 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. Further, because the stock price appreciation milestones are first contingent upon the achievement of a specified clinical milestone, the Company also estimates the fair value of the stock price appreciation milestones based on the probability of achieving the clinical milestone. This assessment is based on several factors including the successful achievement of technological, manufacturing, and regulatory requirements. A small change in the assumptions and other inputs, such as the price of the Company’s common stock, may have a relatively large change in the estimated fair value of the stock price appreciation milestones and associated liability and expense. For example, keeping all other variables constant, a hypothetical 10 % increase in the stock price at March 31, 2023 from $ 5.70 to $ 6.27 per share would have decreased the income recorded during the three months ended March 31, 2023 by $ 0.3 million related to the stock price appreciation milestones. Keeping all other variables constant, a hypothetical 10 % decrease in the stock price at March 31, 2023 from $ 5.70 to $ 5.13 per share would have increased the income recorded during the three months ended March 31, 2023 by $ 0.2 million related to the stock price appreciation milestones. 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, 2022 $ 3,861 Changes in fair value of stock price appreciation milestones liability ( 1,718 ) Balance at March 31, 2023 $ 2,143 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.

Accrued Expenses

Accrued Expenses	3 Months Ended
	Mar. 31, 2023
Payables and Accruals [Abstract]
Accrued Expenses	6. Accrued Expenses Accrued Expenses Current accrued expenses consist of the following (in thousands): March 31, December 31, Accrued payroll and other employee benefits $ 6,034 $ 17,899 Accrued clinical trial related costs 15,250 16,858 Accrued other 10,229 19,175 Total current accrued expenses $ 31,513 $ 53,932

Leases

Leases	3 Months Ended
	Mar. 31, 2023
Leases [Abstract]
Leases	7. Leases The Company has lease agreements for office, laboratory and manufacturing spaces that are classified as operating leases on the unaudited condensed 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 March 31, 2023, future undiscounted mini mum contractual payments under the Company’s operating leases were $ 173.7 million, which will be paid over a remaining weighted-average lease term of 11.3 years. The weighted-average discount rate for the operating lease liabilities was 8.29 %, 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 were as follows (in thousands): Three Months Ended 2023 2022 Straight-line lease expense $ 3,318 $ 3,815 Variable lease expense 613 618 Total operating lease expense $ 3,931 $ 4,433 No short-term lease expense was recognized during the three months ended March 31, 2023 and 2022. Future undiscounted minimum lease payments under the Company’s operating leases as of March 31, 2023 are as follows (in thousands): Operating Remaining 2023 $ 10,760 2024 14,648 2025 15,087 2026 15,540 2027 16,006 2028 15,057 Thereafter 86,580 Total undiscounted lease payments $ 173,678 Less: imputed interest ( 66,063 ) Total lease liability $ 107,615

Convertible Preferred Stock and

Convertible Preferred Stock and Stockholders' Equity	3 Months Ended
	Mar. 31, 2023
Convertible Preferred Stock And Stockholders Deficit Disclosure [Abstract]
Convertible Preferred Stock and Stockholders’ Equity	8. 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 Common Stock outstanding immediately after giving effect to the issuance of shares of Common Stock pursuant to a Notice of Conversion. 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). During the year ended December 31, 2019, 25,000 shares of the Class A Preferred were converted into 125,000 shares of common stock. 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 unaudited condensed 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 March 31, 2023, there wer e 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 March 31, 2023: Number of Weighted- Balance at December 31, 2022 7,267,226 $ 22.37 Granted 5,070,000 6.77 Exercised ( 68,847 ) 3.23 Cancelled ( 394,199 ) 41.46 Balance at March 31, 2023 11,874,180 $ 15.18 Restricted stock unit activity under all equity and stock option plans is summarized as follows: Number of Weighted- Balance at December 31, 2022 5,862,733 $ 48.13 Granted 1,091,540 6.77 Vested ( 827,251 ) 44.06 Cancelled ( 2,156,257 ) 46.10 Balance at March 31, 2023 3,970,765 $ 38.63 The allocation of stock-based compensation for all stock awards is as follows (in thousands): Three Months Ended 2023 2022 Research and development $ 5,056 $ 12,694 General and administrative 5,927 6,637 Total $ 10,983 $ 19,331 As of March 31, 2023, the unrecognized compensation cost related to outstanding options was $ 45.4 million and is expected to be recognized as expense over a weighted-average period of approximately 2.5 years. As of March 31, 2023, the unrecognized compensation cost related to restricted stock units was $ 71.6 million which is expected to be recognized as expense over a weighted-average period of approximately 2.6 years. 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: Three Months Ended 2023 2022 Risk-free interest rate 3.8 % 1.6 % Expected volatility 89.9 % 75.8 % Expected term (in years) 6.4 5.6 Expected dividend yield 0.0 % 0.0 % Reconciliation of Consolidated Stockholders’ Equity Accounts The following table summarizes the Company’s changes in stockholders’ equity accounts for the three months ended March 31, 2023 (in thousands, except share data): Convertible Common Additional Accumulated Accumulated Total Stockholders' Shares Amount Shares Amount Capital Loss Deficit Equity Balance at December 31, 2022 2,794,549 $ 3 97,294,917 $ 97 $ 1,536,497 $ ( 1,854 ) $ ( 1,050,804 ) $ 483,939 Exercise of stock options, net of issuance costs — — 68,847 — 222 — — 222 Issuance of common stock upon vesting of restricted stock units — — 827,251 1 — — — 1 Stock-based compensation — — — — 10,983 — — 10,983 Unrealized gain on investments — — — — — 1,208 — 1,208 Net loss — — — — — — ( 18,881 ) ( 18,881 ) Balance at March 31, 2023 2,794,549 $ 3 98,191,015 $ 98 $ 1,547,702 $ ( 646 ) $ ( 1,069,685 ) $ 477,472 The following table summarizes the Company’s changes in stockholders’ equity accounts for the three months ended March 31, 2022 (in thousands, except share data): Convertible Common Additional Accumulated Accumulated Total Stockholders' Shares Amount Shares Amount Capital Gain (Loss) Deficit Equity Balance at December 31, 2021 2,794,549 $ 3 95,726,962 $ 96 $ 1,448,584 $ ( 762 ) $ ( 769,083 ) $ 678,838 Exercise of stock options, net of issuance costs — — 398,415 — 3,001 — — 3,001 Issuance of common stock upon vesting of restricted stock units — — 412,707 1 — — — 1 Stock-based compensation — — — — 19,331 — — 19,331 Unrealized loss on investments — — — — — ( 2,088 ) — ( 2,088 ) Net loss — — — — — — ( 65,690 ) ( 65,690 ) Balance at March 31, 2022 2,794,549 $ 3 96,538,084 $ 97 $ 1,470,916 $ ( 2,850 ) $ ( 834,773 ) $ 633,393

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2023
Subsequent Events [Abstract]
Subsequent Events [Text Block]	Subsequent Events Preferred Stock 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.

Organization and Summary of S_2

Organization and Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Use of Estimates	Use of Estimates The Company’s unaudited condensed consolidated financial statements are prepared in accordance with United States generally accepted accounting principles (U.S. GAAP). The preparation of the Company’s unaudited condensed consolidated financial statements requires management 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 unaudited condensed consolidated financial statements and accompanying notes. The most significant estimates and assumptions in the Company’s unaudited condensed consolidated financial statements relate to its stock price 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 unaudited condensed 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.
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted Cash Cash and cash equivalents include cash in readily available operating 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 unaudited condensed consolidated balance sheets that sum to the total of the same such amounts shown in the unaudited condensed consolidated statements of cash flows as of March 31, 2023 and 2022 (in thousands): Three Months Ended March 31, 2023 2022 Cash and cash equivalents $ 42,020 $ 64,741 Restricted cash 15,227 15,227 Total cash, cash equivalents, and restricted cash shown in the unaudited condensed consolidated statement of cash flows $ 57,247 $ 79,968 For each of the three months ended March 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 unaudited condensed 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 unaudited condensed 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 unaudited condensed 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.
Unaudited Interim Financial Information	Unaudited Interim Financial Information The accompanying interim condensed consolidated financial statements are unaudited. These unaudited interim condensed consolidated financial statements have been prepared in accordance with U.S. GAAP and following the requirements of the United States Securities and Exchange Commission (SEC) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required can be condensed or omitted. The interim unaudited condensed consolidated financial statements should be read in conjunction with the Company’s financial statements and accompanying notes for the fiscal year ended December 31, 2022, contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022, filed by the Company with the SEC on February 28, 2023. In management’s opinion, the unaudited interim condensed consolidated financial statements have been prepared on the same basis as the audited financial statements and include all adjustments, which include only normal recurring adjustments, necessary for the fair presentation of the Company’s financial position and its results of operations and comprehensive loss and its cash flows for the periods presented. The results for the three months ended March 31, 2023 are not necessarily indicative of the results expected for the full fiscal year or any other interim period or any future year or period.
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. The Company considers the terms of a contract and all relevant facts and circumstances when applying the revenue recognition standard. The Company applies the revenue recognition standard, including the use of any practical expedients, consistently to contracts with similar characteristics and in similar circumstances. A customer is a party that has entered into a contract with the Company, where the purpose of the contract is to obtain a product or a service that is an output of the Company’s ordinary activities in exchange for consideration. To be considered a contract, (i) the contract must be approved (in writing, orally, or in accordance with other customary business practices), (ii) each party’s rights regarding the product or the service to be transferred can be identified, (iii) the payment terms for the product or the service to be transferred can be identified, (iv) the contract must have commercial substance (that is, the risk, timing or amount of future cash flows is expected to change as a result of the contract), and (v) it is probable that the Company will collect substantially all of the consideration to which it is entitled to receive in exchange for the transfer of the product or the service. A performance obligation is defined as a promise to transfer a product or a service to a customer. The Company identifies each promise to transfer a product or a service (or a bundle of products or services, or a series of products and services that are substantially the same and have the same pattern of transfer) that is distinct. A product or a service is distinct if both (i) the customer can benefit from the product or the service either on its own or together with other resources that are readily available to the customer and (ii) the Company’s promise to transfer the product or the service to the customer is separately identifiable from other promises in the contract. Each distinct promise to transfer a product or a service is a unit of accounting for revenue recognition. If a promise to transfer a product or a service is not separately identifiable from other promises in the contract, such promises should be combined into a single performance obligation. The transaction price is the amount of consideration the Company is entitled to receive in exchange for the transfer of control of a product or a service to a customer. To determine the transaction price, the Company considers the existence of any significant financing component, the effects of any variable elements, noncash considerations and consideration payable to the customer. If a significant financing component exists, the transaction price is adjusted for the time value of money. If an element of variability exists, the Company must estimate the consideration it expects to receive and uses that amount as the basis for recognizing revenue as the product or the service is transferred to the customer. There are two methods for determining the amount of variable consideration: (i) the expected value method, which is the sum of probability-weighted amounts in a range of possible consideration amounts, and (ii) the mostly likely amount method, which identifies the single most likely amount in a range of possible consideration amounts. If a contract has multiple performance obligations, the Company allocates the transaction price to each distinct performance obligation in an amount that reflects the consideration the Company is entitled to receive in exchange for satisfying each distinct performance obligation. For each distinct performance obligation, revenue is recognized when (or as) the Company transfers control of the product or the service applicable to such performance obligation. In those instances where the Company first receives consideration in advance of satisfying its performance obligation, the Company classifies such consideration as deferred revenue until (or as) the Company satisfies such performance obligation. In those instances where the Company first satisfies its performance obligation prior to its receipt of consideration, the consideration is recorded as accounts receivable. The Company expenses incremental costs of obtaining and fulfilling a contract as and when incurred if the expected amortization period of the asset that would be recognized is one year or less, or if the amount of the asset is immaterial. Otherwise, such costs are capitalized as contract assets if they are incremental to the contract and amortized to expense proportionate to revenue recognition of the underlying contract.
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, 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 unaudited condensed consolidated statements of operations and comprehensive loss.
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 unaudited condensed 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.
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 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.
Convertible Preferred Stock	Convertible Preferred Stock The Company applies the relevant accounting standards to distinguish liabilities from equity when assessing the classification and measurement of preferred stock. Preferred shares subject to mandatory redemptions are considered liabilities and measured at fair value. Conditionally redeemable preferred shares are considered temporary equity. All other preferred shares are considered as stockholders’ equity. The Company applies the relevant accounting standards for derivatives and hedging (in addition to distinguishing liabilities from equity) when accounting for hybrid contracts that contain conversion options. Conversion options must be bifurcated from the host instruments and accounted for as free-standing financial instruments according to certain criteria. These criteria include circumstances when (i) the economic characteristics and risks of the embedded derivative instruments are not clearly and closely related to the economic characteristics and risks of the host contract, (ii) the hybrid instrument that embodies both the embedded derivative instrument and the host contract is not re-measured at fair value under otherwise applicable accounting principles with changes in fair value reported in earnings as they occurred, and (iii) a separate instrument with the same terms as the embedded derivative instrument would be considered a derivative instrument. The derivative is subsequently measured at fair value at each reporting date, with the changes in fair value reported in earnings.
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, other than losses attributable to a credit loss which are included in other income and expense, on investments classified as available-for-sale securities, which was the only difference between net loss and comprehensive loss for the applicable periods.
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 shares of common stock outstanding for the period, without consideration for common stock equivalents. The Pre-Funded Warrants associated with the January 2021 public equity offering (see Note 8) are considered outstanding shares in the basic earnings per share calculation given their nominal exercise price. Dilutive common stock equivalents for the periods presented include 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 and incentive plans. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding due to the Company’s net loss position. For the three months ended March 31, 2023 , the Company realized a net loss of $ 18.9 million. Shares of potentially dilutive securities totaled 29.8 million for the three months ended March 31, 2023 , including 14.0 million shares associated with a hypothetical conversion of all outstanding shares of the Company’s Class A convertible preferred stock, and an aggregate of 15.8 million shares of common stock issuable upon the exercise of outstanding stock options and the vesting of outstanding restricted stock units. For the three months ended March 31, 2022 , the Company realized a net loss of $ 65.7 million. Shares of potentially dilutive securities totaled 27.7 million for the three months ended March 31, 2022 , including 14.0 million shares associated with a hypothetical conversion of all outstanding shares of the Company’s Class A convertible preferred stock, and an aggregate of 13.7 million shares of common stock issuable upon the exercise of outstanding stock options and the vesting of outstanding restricted stock units.
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.

Organization and Summary of S_3

Organization and Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 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 unaudited condensed consolidated balance sheets that sum to the total of the same such amounts shown in the unaudited condensed consolidated statements of cash flows as of March 31, 2023 and 2022 (in thousands): Three Months Ended March 31, 2023 2022 Cash and cash equivalents $ 42,020 $ 64,741 Restricted cash 15,227 15,227 Total cash, cash equivalents, and restricted cash shown in the unaudited condensed consolidated statement of cash flows $ 57,247 $ 79,968

Collaboration and License Agr_2

Collaboration and License Agreements (Tables)	3 Months Ended
	Mar. 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 Determine the Estimated Fair Value of the Stock Price Appreciation Milestones Payments	The following variables were incorporated in the calculation of the estimated fair value of the stock price appreciation milestones as of March 31, 2023: As of March 31, As of December 31, 2023 2022 Risk-free interest rate 3.6 % 4.0 % Expected volatility 83.9 % 78.1 % Estimated term (in years) 15.8 16.0 Closing stock price as of remeasurement date $ 5.70 $ 10.09

Investments (Tables)

Investments (Tables)	3 Months Ended
	Mar. 31, 2023
Investments [Abstract]
Summary of Investments	The following table summarizes the Company’s investments accounted for as available-for-sale securities as of March 31, 2023 and December 31, 2022 (in thousands, except for maturity in years): Maturity Amortized Unrealized Unrealized Estimated March 31, 2023 Classified as current assets: U.S. Treasury debt securities 1 or less $ 108,628 $ ( 42 ) $ 105 $ 108,691 Non-U.S. government securities 1 or less 2,452 ( 6 ) — 2,446 Municipal securities 1 or less 14,978 ( 118 ) — 14,860 Corporate debt securities 1 or less 102,936 ( 427 ) 7 102,516 Commercial paper 1 or less 138,559 ( 194 ) — 138,365 Total short-term investments $ 367,553 $ ( 787 ) $ 112 $ 366,878 Classified as non-current assets: U.S. Treasury debt securities Greater than 1 $ 3,883 $ — $ 29 $ 3,912 Total long-term investments $ 3,883 $ — $ 29 $ 3,912 December 31, 2022 Classified as current assets: U.S. Treasury debt securities 1 or less $ 79,251 $ ( 263 ) $ 37 $ 79,025 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 123,996 ( 1,138 ) 3 122,861 Commercial paper 1 or less 152,056 ( 230 ) 4 151,830 Total short-term investments $ 376,691 $ ( 1,841 ) $ 44 $ 374,894 Classified as non-current assets: Municipal securities Greater than 1 $ 5,000 $ ( 58 ) $ — $ 4,942 Total long-term investments $ 5,000 $ ( 58 ) $ — $ 4,942
Aggregated by investment category and the length of time	The following tables present gross unrealized losses and fair values for those investments that were in an unrealized loss position as of March 31, 2023 and December 31, 2022, aggregated by investment category and the length of time that individual securities have been in a continuous loss position (in thousands): Less Than 12 Months 12 Months or Greater Total Estimated Fair Value Unrealized Losses Estimated Fair Value Unrealized Losses Estimated Fair Value Unrealized Losses March 31, 2023 U.S. Treasury debt securities $ 37,607 $ ( 42 ) $ — $ — $ 37,607 $ ( 42 ) Non-U.S. government securities 2,446 ( 6 ) — — 2,446 ( 6 ) Municipal securities 4,957 ( 43 ) 9,904 ( 75 ) 14,861 ( 118 ) Corporate debt securities 34,111 ( 111 ) 63,108 ( 316 ) 97,219 ( 427 ) Commercial paper 84,621 ( 194 ) — — 84,621 ( 194 ) Total $ 163,742 $ ( 396 ) $ 73,012 $ ( 391 ) $ 236,754 $ ( 787 ) December 31, 2022 U.S. Treasury debt securities $ 51,246 $ ( 163 ) $ 9,898 $ ( 100 ) $ 61,144 $ ( 263 ) Non-U.S. government securities 2,424 ( 2 ) — — 2,424 ( 2 ) Municipal securities 14,765 ( 193 ) 8,933 ( 73 ) 23,698 ( 266 ) Corporate debt securities 45,621 ( 174 ) 71,625 ( 964 ) 117,246 ( 1,138 ) Commercial paper 66,455 ( 230 ) — — 66,455 ( 230 ) Total $ 180,511 $ ( 762 ) $ 90,456 $ ( 1,137 ) $ 270,967 $ ( 1,899 )

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2023
Fair Value Disclosures [Abstract]
Schedule of Assets Measured at Fair Value on Recurring Basis	The following table presents the Company’s financial assets and liabilities measured at fair value on a recurring basis as of March 31, 2023 and December 31, 2022 (in thousands): Fair Value Measurements at Total Quoted Prices Significant Significant As of March 31, 2023 Financial assets: Money market funds $ 42,020 $ 42,020 $ — $ — U.S. Treasury debt securities 112,603 112,603 — — Non-U.S. government securities 2,446 — 2,446 — Municipal securities 14,860 — 14,860 — Corporate debt securities 102,516 — 102,516 — Commercial paper 138,365 — 138,365 — Total financial assets measured at fair value on a recurring basis $ 412,810 $ 154,623 $ 258,187 $ — Financial liabilities: Stock price appreciation milestones $ 2,143 $ — $ — $ 2,143 Total financial liabilities measured at fair value on a recurring basis $ 2,143 $ — $ — $ 2,143 As of December 31, 2022 Financial assets: Money market funds $ 61,333 $ 61,333 $ — $ — U.S. Treasury debt securities 79,025 79,025 — — Non-U.S. government securities 2,423 — 2,423 — Municipal securities 23,697 — 23,697 — Corporate debt securities 122,861 — 122,861 — Commercial paper 151,830 — 151,830 — Total assets measured at fair value on a recurring basis $ 441,169 $ 140,358 $ 300,811 $ — 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, 2022 $ 3,861 Changes in fair value of stock price appreciation milestones liability ( 1,718 ) Balance at March 31, 2023 $ 2,143

Accrued Expenses (Tables)

Accrued Expenses (Tables)	3 Months Ended
	Mar. 31, 2023
Payables and Accruals [Abstract]
Schedule of accrued expenses	Current accrued expenses consist of the following (in thousands): March 31, December 31, Accrued payroll and other employee benefits $ 6,034 $ 17,899 Accrued clinical trial related costs 15,250 16,858 Accrued other 10,229 19,175 Total current accrued expenses $ 31,513 $ 53,932

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2023
Leases [Abstract]
Schedule of Components of Lease Expense	The components of lease expense were as follows (in thousands): Three Months Ended 2023 2022 Straight-line lease expense $ 3,318 $ 3,815 Variable lease expense 613 618 Total operating lease expense $ 3,931 $ 4,433
Schedule of Future Minimum Payments Under Non-cancelable Operating Leases	Future undiscounted minimum lease payments under the Company’s operating leases as of March 31, 2023 are as follows (in thousands): Operating Remaining 2023 $ 10,760 2024 14,648 2025 15,087 2026 15,540 2027 16,006 2028 15,057 Thereafter 86,580 Total undiscounted lease payments $ 173,678 Less: imputed interest ( 66,063 ) Total lease liability $ 107,615

Convertible Preferred Stock a_2

Convertible Preferred Stock and Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2023
Convertible Preferred Stock And Stockholders Equity 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 March 31, 2023: Number of Weighted- Balance at December 31, 2022 7,267,226 $ 22.37 Granted 5,070,000 6.77 Exercised ( 68,847 ) 3.23 Cancelled ( 394,199 ) 41.46 Balance at March 31, 2023 11,874,180 $ 15.18
Summary of restricted stock unit activity under the Plan	Restricted stock unit activity under all equity and stock option plans is summarized as follows: Number of Weighted- Balance at December 31, 2022 5,862,733 $ 48.13 Granted 1,091,540 6.77 Vested ( 827,251 ) 44.06 Cancelled ( 2,156,257 ) 46.10 Balance at March 31, 2023 3,970,765 $ 38.63
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): Three Months Ended 2023 2022 Research and development $ 5,056 $ 12,694 General and administrative 5,927 6,637 Total $ 10,983 $ 19,331
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: Three Months Ended 2023 2022 Risk-free interest rate 3.8 % 1.6 % Expected volatility 89.9 % 75.8 % Expected term (in years) 6.4 5.6 Expected dividend yield 0.0 % 0.0 %
Summary of changes in stockholders' equity	The following table summarizes the Company’s changes in stockholders’ equity accounts for the three months ended March 31, 2023 (in thousands, except share data): Convertible Common Additional Accumulated Accumulated Total Stockholders' Shares Amount Shares Amount Capital Loss Deficit Equity Balance at December 31, 2022 2,794,549 $ 3 97,294,917 $ 97 $ 1,536,497 $ ( 1,854 ) $ ( 1,050,804 ) $ 483,939 Exercise of stock options, net of issuance costs — — 68,847 — 222 — — 222 Issuance of common stock upon vesting of restricted stock units — — 827,251 1 — — — 1 Stock-based compensation — — — — 10,983 — — 10,983 Unrealized gain on investments — — — — — 1,208 — 1,208 Net loss — — — — — — ( 18,881 ) ( 18,881 ) Balance at March 31, 2023 2,794,549 $ 3 98,191,015 $ 98 $ 1,547,702 $ ( 646 ) $ ( 1,069,685 ) $ 477,472 The following table summarizes the Company’s changes in stockholders’ equity accounts for the three months ended March 31, 2022 (in thousands, except share data): Convertible Common Additional Accumulated Accumulated Total Stockholders' Shares Amount Shares Amount Capital Gain (Loss) Deficit Equity Balance at December 31, 2021 2,794,549 $ 3 95,726,962 $ 96 $ 1,448,584 $ ( 762 ) $ ( 769,083 ) $ 678,838 Exercise of stock options, net of issuance costs — — 398,415 — 3,001 — — 3,001 Issuance of common stock upon vesting of restricted stock units — — 412,707 1 — — — 1 Stock-based compensation — — — — 19,331 — — 19,331 Unrealized loss on investments — — — — — ( 2,088 ) — ( 2,088 ) Net loss — — — — — — ( 65,690 ) ( 65,690 ) Balance at March 31, 2022 2,794,549 $ 3 96,538,084 $ 97 $ 1,470,916 $ ( 2,850 ) $ ( 834,773 ) $ 633,393

Organization and Summary of S_4

Organization and Summary of Significant Accounting Policies (Details) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended
	Jan. 31, 2021 $ / shares shares	Mar. 31, 2023 USD ($) Employees shares	Mar. 31, 2022 USD ($) shares
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of number of employee reduced		60%
Restructuring And Related Cost Number Of Positions Retained | Employees		220
Net loss		$ (18,881)	$ (65,690)
Potentially dilutive securities (in shares) | shares		29,800,000	27,700,000
Letters of credit outstanding amount		$ 15,200	$ 15,200
Employee termination related costs		12,900
Research and development expense		10,900
General And Administrative Expense		2,000
Operating Expenses		$ 87,572	$ 92,881
Restricted Stock Units (RSUs)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potentially dilutive securities (in shares) | shares		15,800,000	13,700,000
Class A Convertible Preferred Stock
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Net loss		$ 18,900
Potentially dilutive securities (in shares) | shares		14,000,000	14,000,000
Pre-Funded Warrants
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of shares to be purchased | shares	257,310	257,310
Purchase price of prefunded warrants | $ / shares	$ 85.499
Exercise price of warrants | $ / shares	$ 0.001

Organization and Summary of S_5

Organization and Summary of Significant Accounting Policies (Details 2) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents	$ 42,020	$ 61,333	$ 64,741
Restricted cash	15,227		15,227
Total cash, cash equivalents, and restricted cash shown in the unaudited condensed consolidated statement of cash flows	$ 57,247	$ 76,560	$ 79,968	$ 148,810

Collaboration and License Agr_3

Collaboration and License Agreements - Janssen Collaboration and Option Agreement (Details) - USD ($)				1 Months Ended	3 Months Ended
	Nov. 07, 2022	Apr. 02, 2020	Sep. 14, 2018	Jun. 30, 2020	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaboration contract asset					$ 0		$ 7,196,000
Revenue recognized					58,980,000	$ 18,414,000
Commercial option exercise
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue recognized					10,000
Janssen Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sublicense Consideration Represents an Asset Under ASC, Other Assets and Deferred Costs					17,100,000
Janssen Biotech Inc
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaboration contract asset					17,100,000
Amortization of sublicense consideration					7,200,000	1,100,000
Revenue recognized					52,300,000	15,900,000
Deferred revenue					41,200,000
Research and development fees cash payments received					82,000,000
Janssen Biotech Inc | Research And Development
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue recognized					11,100,000	9,800,000
Janssen Biotech Inc | Upfront Fee and Equity Premium
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue recognized					31,200,000	6,100,000
Ono Pharmaceutical Co. Ltd
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Transaction price of the agreement			$ 39,300,000
Non-refundable upfront payments recorded as deferred revenue			$ 10,000,000
Option exercise payment	$ 12,500,000
Collaboration contract asset					7,800,000
Amortization of sublicense consideration						$ 300,000
Revenue recognized					6,700,000
Research and development fees cash payments received					$ 29,200,000
Johnson Johnson Innovation J J D C Inc | Stock Purchase Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Common stock per share				$ 28.31
Aggregate purchase price of common stock		$ 50,000,000
Company Received Payment		100,000,000
Upfront Cash Payment		50,000,000
Equity Method Investment, Underlying Equity in Net Assets		$ 50,000,000
Equity premium per share		$ 9.93
Aggregate equity premium on shares		$ 16,000,000
Proceeds from Issuance of Private Placement		$ 34,000,000
Issuance of common stock during period for private placements (in shares)				1.8

Collaboration and License Agr_4

Collaboration and License Agreements - Ono Collaboration and Option Agreement (Details) - USD ($) $ in Thousands			1 Months Ended		3 Months Ended
	Nov. 07, 2022	Sep. 14, 2018	Jun. 30, 2022	Oct. 31, 2018	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022	Dec. 31, 2020
Collaboration agreement
Collaboration contract asset					$ 0		$ 7,196
Revenue recognized					$ 58,980	$ 18,414
Expected Ressarch Services Period					4 years
Ono Pharmaceutical Co. Ltd
Collaboration agreement
Collaborative arrangement annual payments receivable recorded as deferred revenue		$ 10,000
Non-refundable upfront payments recorded as deferred revenue		10,000
Aggregate research and development fees payments receivable		20,000
Collaborative arrangement annual payments receivable recorded as deferred revenue				$ 5,000
Transaction price of the agreement		$ 39,300
Collaboration contract asset					$ 7,800
Amortization of sublicense consideration						300
Revenue recognized					6,700
Research and development fees cash payments received					29,200
contra-research and development expense					1,000
Option exercise payment	$ 12,500
Ono Pharmaceutical Co. Ltd | Candidate 2
Collaboration agreement
Percentage of reduction on milestone payments		50%
Ono Pharmaceutical Co. Ltd | Minimum | Candidate 1
Collaboration agreement
Profits and losses sharing percentage			50%
Collaborative arrangement potential additional milestones			$ 9,300
Ono Pharmaceutical Co. Ltd | Maximum | Candidate 1
Collaboration agreement
Collaborative arrangement potential additional milestones		$ 29,300	$ 29,300
Ono Pharmaceutical Co. Ltd | Maximum | Candidate 2
Collaboration agreement
Aggregate milestone payments		$ 843,000
Ono Pharmaceutical Co. Ltd | Collaborative Arrangement
Collaboration agreement
Revenue recognized					2,500
Ono Pharmaceutical Co. Ltd | Collaborative Arrangement | Upfront Fee
Collaboration agreement
Revenue recognized						1,300
Ono Letter Agreement | Ono Pharmaceutical Co. Ltd
Collaboration agreement
Milestone payments								$ 10,000
Revenue recognized						$ 1,200
Ono Letter Agreement | Ono Pharmaceutical Co. Ltd | Sublicense Consideration
Collaboration agreement
Sublicense consideration paid					$ 7,800

Collaboration and License Agr_5

Collaboration and License Agreements - Memorial Sloan Kettering Cancer Center License Agreement (Details) - Amended MSK License - USD ($)	3 Months Ended
	Mar. 31, 2023	Dec. 31, 2021
Collaboration agreement
Enterprise value milestone payment	$ 75,000,000
Stock price appreciation milestone payable		$ 20,000,000
Enterprise value milestones liability at fair value	2,100
Stock price appreciation milestone, income	$ 1,700,000

Collaboration and License Agr_6

Collaboration and License Agreements (Details 1) - Amended MSK License $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 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 (in millions) | $	$ 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 (in millions) | $	$ 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 (in millions) | $	$ 25

Collaboration and License Agr_7

Collaboration and License Agreements (Details 2) - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Determine the estimated fair value of the enterprise value milestone payments
Closing stock price as of re measurement date	$ 5.70
Amended MSK License
Determine the estimated fair value of the enterprise value milestone payments
Risk-free interest rate	3.60%	4%
Expected volatility	83.90%	78.10%
Estimated term (in years)	15 years 9 months 18 days	16 years
Closing stock price as of re measurement date	$ 5.70	$ 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 ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities, impairment	$ 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, Non-U.S. Government Securities, Municipal Securities, Corporate Debt Securities and Commercial Paper
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	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
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	$ 108,628	$ 79,251
Unrealized Losses	(42)	(263)
Unrealised Gains	105	37
Estimated Fair Value	$ 108,691	$ 79,025
U.S. Treasury debt securities | Non-current Assets [Member]
Schedule Of Available For Sale Securities [Line Items]
Maturity (in years)	Greater than 1
Amortized Cost	$ 3,883
Unrealized Losses	0
Unrealised Gains	29
Estimated Fair Value	$ 3,912
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	$ 2,452	$ 2,425
Unrealized Losses	(6)	(2)
Unrealised Gains	0	0
Estimated Fair Value	$ 2,446	$ 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	$ 14,978	$ 18,963
Unrealized Losses	(118)	(208)
Unrealised Gains	0	0
Estimated Fair Value	$ 14,860	$ 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)
Unrealised 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	$ 102,936	$ 123,996
Unrealized Losses	(427)	(1,138)
Unrealised Gains	7	3
Estimated Fair Value	$ 102,516	$ 122,861
Commercial Paper | Current Assets [Member]
Schedule Of Available For Sale Securities [Line Items]
Maturity (in years)	1 or less	1 or less
Amortized Cost	$ 138,559	$ 152,056
Unrealized Losses	(194)	(230)
Unrealised Gains	0	4
Estimated Fair Value	138,365	151,830
Short-term Investments [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	367,553	376,691
Unrealized Losses	(787)	(1,841)
Unrealised Gains	112	44
Estimated Fair Value	366,878	374,894
Long-term Investments [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	3,883	5,000
Unrealized Losses	0	(58)
Unrealised Gains	29	0
Estimated Fair Value	$ 3,912	$ 4,942

Investments (Details 3) - Short

Investments (Details 3) - Short Term Investment (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-Sale [Line Items]
Estimated Fair Value, Total	$ 236,754	$ 270,967
Unrealized Losses, Total	(787)	(1,899)
U.S. Treasury debt securities
Debt Securities, Available-for-Sale [Line Items]
Estimated Fair Value, Total	37,607	61,144
Unrealized Losses, Total	(42)	(263)
Non-U.S. government securities
Debt Securities, Available-for-Sale [Line Items]
Estimated Fair Value, Total	2,446	2,424
Unrealized Losses, Total	(6)	(2)
Municipal securities
Debt Securities, Available-for-Sale [Line Items]
Estimated Fair Value, Total	14,861	23,698
Unrealized Losses, Total	(118)	(266)
Corporate debt securities
Debt Securities, Available-for-Sale [Line Items]
Estimated Fair Value, Total	97,219	117,246
Unrealized Losses, Total	(427)	(1,138)
Commercial Paper
Debt Securities, Available-for-Sale [Line Items]
Estimated Fair Value, Total	84,621	66,455
Unrealized Losses, Total	(194)	(230)
Short-term Investments [Member]
Debt Securities, Available-for-Sale [Line Items]
Estimated Fair Value, Less Than 12 Months	163,742	180,511
Unrealized Losses, Less Than 12 Months	(396)	(762)
Short-term Investments [Member] | U.S. Treasury debt securities
Debt Securities, Available-for-Sale [Line Items]
Estimated Fair Value, Less Than 12 Months	37,607	51,246
Unrealized Losses, Less Than 12 Months	(42)	(163)
Short-term Investments [Member] | Non-U.S. government securities
Debt Securities, Available-for-Sale [Line Items]
Estimated Fair Value, Less Than 12 Months	2,446	2,424
Unrealized Losses, Less Than 12 Months	(6)	(2)
Short-term Investments [Member] | Municipal securities
Debt Securities, Available-for-Sale [Line Items]
Estimated Fair Value, Less Than 12 Months	4,957	14,765
Unrealized Losses, Less Than 12 Months	(43)	(193)
Short-term Investments [Member] | Corporate debt securities
Debt Securities, Available-for-Sale [Line Items]
Estimated Fair Value, Less Than 12 Months	34,111	45,621
Unrealized Losses, Less Than 12 Months	(111)	(174)
Short-term Investments [Member] | Commercial Paper
Debt Securities, Available-for-Sale [Line Items]
Estimated Fair Value, Less Than 12 Months	84,621	66,455
Unrealized Losses, Less Than 12 Months	(194)	(230)
Long-term Investments [Member]
Debt Securities, Available-for-Sale [Line Items]
Estimated Fair Value, 12 Months or Greater	73,012	90,456
Unrealized Losses, 12 Months or Greater	(391)	(1,137)
Long-term Investments [Member] | U.S. Treasury debt securities
Debt Securities, Available-for-Sale [Line Items]
Estimated Fair Value, 12 Months or Greater	0	9,898
Unrealized Losses, 12 Months or Greater	0	(100)
Long-term Investments [Member] | Non-U.S. government securities
Debt Securities, Available-for-Sale [Line Items]
Estimated Fair Value, 12 Months or Greater	0	0
Unrealized Losses, 12 Months or Greater	0	0
Long-term Investments [Member] | Municipal securities
Debt Securities, Available-for-Sale [Line Items]
Estimated Fair Value, 12 Months or Greater	9,904	8,933
Unrealized Losses, 12 Months or Greater	(75)	(73)
Long-term Investments [Member] | Corporate debt securities
Debt Securities, Available-for-Sale [Line Items]
Estimated Fair Value, 12 Months or Greater	63,108	71,625
Unrealized Losses, 12 Months or Greater	(316)	(964)
Long-term Investments [Member] | Commercial Paper
Debt Securities, Available-for-Sale [Line Items]
Estimated Fair Value, 12 Months or Greater	0	0
Unrealized Losses, 12 Months or Greater	$ 0	$ 0

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Quoted prices in Active Market for Identical Assets (Level 1) | Money market funds
Financial assets:
Money market funds	$ 42,020	$ 61,333
Quoted prices in Active Market for Identical Assets (Level 1) | U.S. Treasury debt securities
Financial assets:
Money market funds	112,603
Investment		79,025
Significant Other Observable Inputs (Level 2) | Non-U.S. government securities
Financial assets:
Investment	2,446	2,423
Significant Other Observable Inputs (Level 2) | Municipal securities
Financial assets:
Investment	14,860	23,697
Significant Other Observable Inputs (Level 2) | Corporate debt securities
Financial assets:
Investment	102,516	122,861
Significant Other Observable Inputs (Level 2) | Commercial Paper
Financial assets:
Investment	138,365	151,830
Fair Value Measurements Recurring
Financial assets:
Total financial assets measured at fair value on a recurring basis	412,810	441,169
Financial liabilities:
Total financial liabilities measured at fair value on a recurring basis	2,143	3,861
Fair Value Measurements Recurring | Stock price appreciation milestones
Financial liabilities:
Stock price appreciation milestones	2,143	3,861
Fair Value Measurements Recurring | Money market funds
Financial assets:
Money market funds	42,020	61,333
Fair Value Measurements Recurring | U.S. Treasury debt securities
Financial assets:
Money market funds	112,603
Investment		79,025
Fair Value Measurements Recurring | Non-U.S. government securities
Financial assets:
Money market funds	2,446
Investment		2,423
Fair Value Measurements Recurring | Municipal securities
Financial assets:
Money market funds	14,860
Investment		23,697
Fair Value Measurements Recurring | Corporate debt securities
Financial assets:
Money market funds	102,516
Investment		122,861
Fair Value Measurements Recurring | Commercial Paper
Financial assets:
Money market funds	138,365
Investment		151,830
Fair Value Measurements Recurring | Quoted prices in Active Market for Identical Assets (Level 1)
Financial assets:
Total financial assets measured at fair value on a recurring basis	154,623	140,358
Financial liabilities:
Total financial liabilities measured at fair value on a recurring basis	0
Fair Value Measurements Recurring | Significant Other Observable Inputs (Level 2)
Financial assets:
Total financial assets measured at fair value on a recurring basis	258,187	300,811
Financial liabilities:
Total financial liabilities measured at fair value on a recurring basis	0
Fair Value Measurements Recurring | Significant Unobservable Inputs (Level 3)
Financial assets:
Total financial assets measured at fair value on a recurring basis	0	0
Financial liabilities:
Total financial liabilities measured at fair value on a recurring basis	2,143	3,861
Fair Value Measurements Recurring | Significant Unobservable Inputs (Level 3) | Stock price appreciation milestones
Financial liabilities:
Stock price appreciation milestones	$ 2,143	$ 3,861

Fair Value Measurements (Deta_2

Fair Value Measurements (Details 2) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Closing stock price as of re measurement date	$ 5.70
Change in fair value of stock price appreciation milestones	$ (1,718,000)	$ (8,359,000)
FairValueAssetsLevel1ToLevel2TransfersAmounts	0
FairValueAssetsLevel2ToLevel1TransfersAmounts	0
FairValueLiabilitiesLevel1ToLevel2TransfersAmounts	0
FairValueLiabilitiesLevel2ToLevel1TransfersAmounts	0
Fair Value Measurements Nonrecurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Change in fair value of stock price appreciation milestones	300,000
Financial assets/ Non-financial assets	$ 0
Stock price increased by 10% per share
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Sensitivity analysis fair value inputs stock price increase/decrease	10%
Sensitivity analysis share price fair value input	$ 6.27
Change in fair value of stock price appreciation milestones	$ 200,000
Stock price decreased by 10% per share
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Sensitivity analysis fair value inputs stock price increase/decrease	10%
Sensitivity analysis share price fair value input	$ 5.13

Fair Value Measurements (Deta_3

Fair Value Measurements (Details 3) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Change in fair value of stock price appreciation milestones	$ (1,718)	$ (8,359)
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
Change in fair value of stock price appreciation milestones	(1,718)
Balance at the end of the period	$ 2,143

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Current accrued expenses
Accrued payroll and other employee benefits	$ 6,034	$ 17,899
Accrued clinical trial related costs	15,250	16,858
Accrued other	10,229	19,175
Total current accrued expenses	$ 31,513	$ 53,932

Leases (Details)

Leases (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 31, 2020	Mar. 31, 2023	Mar. 31, 2022	Jun. 30, 2022
Lessee Lease Description [Line Items]
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
Lessee, operating lease, existence of option to extend				true
Future minimum payments under the operating leases		$ 173,678
Remaining weighted-average lease term		11 years 3 months 18 days
Operating lease liabilities, weighted-average discount rate		8.29%
Total short-term lease expense		$ 0	$ 0
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		$ 173,700
Maximum
Lessee Lease Description [Line Items]
Lease term		16 years
Maximum | The Premises 2020 Lease Agreement
Lessee Lease Description [Line Items]
Renewal term		10 years

Leases (Details 1)

Leases (Details 1) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Lease, Cost [Abstract]
Straight-line lease expense	$ 3,318	$ 3,815
Variable lease expense	613	618
Total operating lease expense	$ 3,931	$ 4,433

Leases (Details 2)

Leases (Details 2) $ in Thousands	Mar. 31, 2023 USD ($)
Lessee, Operating Lease, Liability, to be Paid [Abstract]
Remaining 2023	$ 10,760
2024	14,648
2025	15,087
2026	15,540
2027	16,006
2028	15,057
Thereafter	86,580
Total undiscounted lease payments	173,678
Less: imputed interest	(66,063)
Total lease liability	$ 107,615

Convertible Preferred Stock a_3

Convertible Preferred Stock and Stockholders' Equity (Additional information) (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended		3 Months Ended	12 Months Ended
	Jan. 31, 2021	Nov. 30, 2016	Mar. 31, 2023	Dec. 31, 2019	Dec. 31, 2022	May 02, 2017
Convertible preferred stock
Preferred stock, par value (in dollars per share)			$ 0.001		$ 0.001
Employee And Non Employee Stock Option
Convertible preferred stock
Unrecognized compensation cost related to outstanding options			$ 45.4
Expected recognition weighted average period of unrecognized compensation cost			2 years 6 months
Restricted Stock Units (RSUs)
Convertible preferred stock
Expected recognition weighted average period of unrecognized compensation cost			2 years 7 months 6 days
Unrecognized compensation cost related to unvested restricted shares			$ 71.6
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%
Common Stock
Convertible preferred stock
Conversion of preferred shares to common stock				125,000
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 | Maximum
Convertible preferred stock
Number of shares to be issued upon conversion						14,097,745
Non-Voting Class A Preferred Stock | Maximum | Redmile Group, LLC and Affiliates
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			2,794,549		2,794,549
Conversion of preferred shares to common stock				25,000
Class A Convertible Preferred Shares | Redmile Group, LLC and Affiliates
Convertible preferred stock
Percentage of common stock ownership upon preferred stock conversion		19.99%
November 2016 Placement | Common Stock
Convertible preferred stock
Share issue price (in dollars per share)		$ 2.66
Common stock issued		7,236,837
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)		$ 13.30
Number of shares to be issued upon conversion		5
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	3 Months Ended
	Mar. 31, 2023 $ / shares shares
Number of Options
Balance at the beginning of the period | shares	7,267,226
Granted | shares	5,070,000
Exercised | shares	(68,847)
Cancelled | shares	(394,199)
Balance at the end of the period | shares	11,874,180
Weighted-Average Price
Balance at the beginning of the period | $ / shares	$ 22.37
Granted | $ / shares	6.77
Exercised | $ / shares	3.23
Cancelled | $ / shares	41.46
Balance at the end of the period | $ / shares	$ 15.18

Convertible Preferred Stock a_5

Convertible Preferred Stock and Stockholders' Equity - Restricted stock unit activity under all equity and stock option plans (Details) - Restricted Stock Units (RSUs)	3 Months Ended
	Mar. 31, 2023 $ / shares shares
Number of Restricted Stock Units
Balance at the beginning of the period | shares	5,862,733
Granted | shares	1,091,540
Vested | shares	(827,251)
Cancelled | shares	(2,156,257)
Balance at the end of the period | shares	3,970,765
Weighted-Average Grant Date Fair Value per Share
Balance at the beginning of the period | $ / shares	$ 48.13
Granted | $ / shares	6.77
Vested | $ / shares	44.06
Cancelled | $ / shares	46.10
Balance at the end of the period | $ / shares	$ 38.63

Convertible Preferred Stock a_6

Convertible Preferred Stock and Stockholders' Equity - Stock based compensation for all stock awards (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Convertible preferred stock
Total stock-based compensation expense	$ 10,983	$ 19,331
Research And Development
Convertible preferred stock
Total stock-based compensation expense	5,056	12,694
General And Administrative
Convertible preferred stock
Total stock-based compensation expense	$ 5,927	$ 6,637

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	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Weighted-average assumptions to determine fair value of stock options
Risk-free interest rate	3.80%	1.60%
Expected volatility	89.90%	75.80%
Expected term (in years)	6 years 4 months 24 days	5 years 7 months 6 days
Expected dividend yield	0%	0%

Convertible Preferred Stock a_8

Convertible Preferred Stock and Stockholders' Equity (Details 6) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Class Of Stock [Line Items]
Balance	$ 483,939	$ 678,838
Exercise of stock options, net of issuance costs	222	3,001
Issuance of common stock upon vesting of restricted stock units	1	1
Stock-based compensation	10,983	19,331
Unrealized gain (loss) on investments	1,208	(2,088)
Net loss	(18,881)	(65,690)
Balance	$ 477,472	$ 633,393
Class A Convertible Preferred Shares
Class Of Stock [Line Items]
Balance (in shares)	2,794,549	2,794,549
Net loss	$ 18,900
Balance (in shares)	2,794,549	2,794,549
Preferred Stock | Class A Convertible Preferred Shares
Class Of Stock [Line Items]
Balance	$ 3	$ 3
Balance	3	3
Common Stock
Class Of Stock [Line Items]
Balance	$ 97	$ 96
Balance (in shares)	97,294,917	95,726,962
Exercise of stock options, net of issuance costs (in shares)	68,847	398,415
Issuance of common stock upon vesting of restricted stock units	$ 1	$ 1
Issuance of common stock upon vesting of restricted stock units (in shares)	827,251	412,707
Balance	$ 98	$ 97
Balance (in shares)	98,191,015	96,538,084
Additional Paid In Capital
Class Of Stock [Line Items]
Balance	$ 1,536,497	$ 1,448,584
Exercise of stock options, net of issuance costs	222	3,001
Stock-based compensation	10,983	19,331
Balance	1,547,702	1,470,916
Accumulated Other Comprehensive Gain (Loss)
Class Of Stock [Line Items]
Balance	(1,854)	(762)
Unrealized gain (loss) on investments	1,208	(2,088)
Balance	(646)	(2,850)
Accumulated Deficit
Class Of Stock [Line Items]
Balance	(1,050,804)	(769,083)
Net loss	(18,881)	(65,690)
Balance	$ (1,069,685)	$ (834,773)

Subsequent Events (Additional I

Subsequent Events (Additional Information) (Details) - Subsequent Event [Member]	1 Months Ended
	Apr. 30, 2023
Subsequent Event [Line Items]
Preferred Stock, Convertible, Terms	33,441
Common Stock, Conversion Basis	167,205