Lyell Immunopharma (LYEL) 10-Q 8 Nov 22 2022 Q3 Quarterly report Financial data

Cover

Cover - shares	9 Months Ended
	Sep. 30, 2022	Nov. 03, 2022
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2022
Document Transition Report	false
Entity File Number	001-40502
Entity Registrant Name	Lyell Immunopharma, Inc.
Entity Incorporation State Country Code	DE
Entity Tax Identification Number	83-1300510
Entity Address Line1	201 Haskins Way
Entity Address City Or Town	South San Francisco
Entity Address State Or Province	CA
Entity Address Postal Zip Code	94080
City Area Code	650
Local Phone Number	695-0677
Security12b Title	Common Stock, $0.0001 par value per share
Trading Symbol	LYEL
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		249,325,627
Entity Central Index Key	0001806952
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q3
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands		Sep. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents		$ 116,311	$ 293,828
Marketable securities		531,821	320,966
Prepaid expenses and other current assets		11,613	11,492
Total current assets		659,745	626,286
Restricted cash		279	466
Marketable securities, non-current		102,519	283,531
Other investments		42,001	47,001
Property and equipment, net		125,727	120,098
Operating lease right-of-use assets		44,084	46,541
Other non-current assets		2,914	3,483
Total assets		977,269	1,127,406
Current liabilities:
Accounts payable		4,795	3,207
Accrued liabilities and other current liabilities		23,568	29,057
Success payment liabilities		11,663	9,486
Deferred revenue	[1]	11,191	4,988
Total current liabilities		51,217	46,738
Operating lease liabilities, non-current		64,636	66,650
Deferred revenue, non-current	[2]	37,163	79,665
Other non-current liabilities		4,227	4,566
Total liabilities		157,243	197,619
Commitments and contingencies (Note 12)
Stockholders’ equity:
Preferred stock, $0.0001 par value; 10,000 shares authorized at September 30, 2022 and December 31, 2021; zero shares issued and outstanding at September 30, 2022 and December 31, 2021		0	0
Common stock, $0.0001 par value; 500,000 shares authorized at September 30, 2022 and December 31, 2021; 249,240 and 242,738 shares issued and outstanding at September 30, 2022 and December 31, 2021, respectively		25	24
Additional paid-in capital		1,589,080	1,515,748
Accumulated other comprehensive loss		(9,996)	(1,623)
Accumulated deficit		(759,083)	(584,362)
Total stockholders’ equity		820,026	929,787
Total liabilities and stockholders’ equity		$ 977,269	$ 1,127,406
[1]Including amounts from a related-party of $11,191 and $4,988 as of September 30, 2022 and December 31, 2021, respectively.[2]Including amounts from a related-party of $37,163 and $79,665 as of September 30, 2022 and December 31, 2021, respectively.

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock authorized (in shares)	10,000,000	10,000,000
Preferred stock issued (in shares)	0	0
Preferred stock outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock authorized (in shares)	500,000,000	500,000,000
Common stock issued (in shares)	249,240,000	242,738,000
Common stock outstanding (in shares)	249,239,833	242,738,350
Due to related parties, current	$ 11,191	$ 4,988
Due to related parties, noncurrent	$ 37,163	$ 79,665

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Statement of Comprehensive Income [Abstract]
Revenue	[1]	$ 3	$ 2,755	$ 36,297	$ 7,828
Operating expenses:
Research and development		41,607	31,433	121,156	119,408
General and administrative		26,084	21,241	90,959	57,184
Other operating income, net		(1,251)	(758)	(3,544)	(1,526)
Total operating expenses		66,440	51,916	208,571	175,066
Loss from operations		(66,437)	(49,161)	(172,274)	(167,238)
Interest income, net		2,251	270	3,600	842
Other (expense) income, net		(1,068)	16	(1,047)	(117)
Impairment of other investments		(5,000)	0	(5,000)	0
Total other (loss) income, net		(3,817)	286	(2,447)	725
Net loss		(70,254)	(48,875)	(174,721)	(166,513)
Other comprehensive loss:
Net unrealized loss on marketable securities		(1,645)	(138)	(8,373)	(321)
Comprehensive loss		$ (71,899)	$ (49,013)	$ (183,094)	$ (166,834)
Net loss per common share, basic (in dollars per share)		$ (0.28)	$ (0.20)	$ (0.71)	$ (1.66)
Net loss per common share, diluted (in dollars per share)		$ (0.28)	$ (0.20)	$ (0.71)	$ (1.66)
Weighted-average shares used to compute net loss per common share, basic (in shares)		248,320	239,384	246,285	100,603
Weighted-average shares used to compute net loss per common share, diluted (in shares)		248,320	239,384	246,285	100,603
[1]Including related-party revenue of zero and $2,640 for the three months ended September 30, 2022 and 2021, respectively, and $36,299 and $7,697 for the nine months ended September 30, 2022 and 2021, respectively.

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Operations and Comprehensive Loss (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Statement of Comprehensive Income [Abstract]
Revenue recognized from related parties	$ 0	$ 2,640	$ 36,299	$ 7,697

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2020		194,474,000
Beginning balance at Dec. 31, 2020		$ 1,010,968
Increase (Decrease) in Temporary Equity [Roll Forward]
Conversion of convertible preferred stock to common stock (in shares)		(194,474,000)
Conversion of convertible preferred stock to common stock		$ (1,010,968)
Ending balance (in shares) at Sep. 30, 2021		0
Ending balance at Sep. 30, 2021		$ 0
Beginning balance (in shares) at Dec. 31, 2020			15,570,000
Beginning balance at Dec. 31, 2020	$ (292,528)		$ 2	$ 41,357	$ 256	$ (334,143)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Proceeds from initial public offering, net of $33,198 in issuance costs (in shares)			25,000,000
Proceeds from initial public offering, net of $33,198 in issuance costs	391,802		$ 2	391,800
Conversion of convertible preferred stock to common stock (in shares)			194,474,000
Conversion of convertible preferred stock to common stock	1,010,968		$ 20	1,010,948
Issuance of common stock upon exercise of stock options (in shares)			776,000
Issuance of common stock upon exercise of stock options	2,043			2,043
Stock-based compensation (in shares)			3,969,000
Stock-based compensation	41,023			41,023
Other comprehensive loss	(321)				(321)
Net loss	(166,513)					(166,513)
Ending balance (in shares) at Sep. 30, 2021			239,789,000
Ending balance at Sep. 30, 2021	986,474		$ 24	1,487,171	(65)	(500,656)
Beginning balance (in shares) at Jun. 30, 2021		0
Beginning balance at Jun. 30, 2021		$ 0
Ending balance (in shares) at Sep. 30, 2021		0
Ending balance at Sep. 30, 2021		$ 0
Beginning balance (in shares) at Jun. 30, 2021			238,549,000
Beginning balance at Jun. 30, 2021	1,021,955		$ 24	1,473,639	73	(451,781)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Proceeds from initial public offering, net of $33,198 in issuance costs	(39)			(39)
Issuance of common stock upon exercise of stock options (in shares)			265,000
Issuance of common stock upon exercise of stock options	529			529
Stock-based compensation (in shares)			975,000
Stock-based compensation	13,042			13,042
Other comprehensive loss	(138)				(138)
Net loss	(48,875)					(48,875)
Ending balance (in shares) at Sep. 30, 2021			239,789,000
Ending balance at Sep. 30, 2021	$ 986,474		$ 24	1,487,171	(65)	(500,656)
Beginning balance (in shares) at Dec. 31, 2021	0
Ending balance (in shares) at Sep. 30, 2022	0
Beginning balance (in shares) at Dec. 31, 2021	242,738,350		242,738,000
Beginning balance at Dec. 31, 2021	$ 929,787		$ 24	1,515,748	(1,623)	(584,362)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)	3,512,765		3,513,000
Issuance of common stock upon exercise of stock options	$ 9,252		$ 1	9,251
Stock-based compensation (in shares)			2,600,000
Stock-based compensation	63,561			63,561
Issuance of common stock under employee stock purchase plan (in shares)			284,000
Issuance of common stock under employee stock purchase plan	887			887
Issuance of common stock in connection with restricted stock units, net of tax (in shares)			105,000
Issuance of common stock in connection with restricted stock units, net of tax	(367)			(367)
Other comprehensive loss	(8,373)				(8,373)
Net loss	$ (174,721)					(174,721)
Ending balance (in shares) at Sep. 30, 2022	249,239,833		249,240,000
Ending balance at Sep. 30, 2022	$ 820,026		$ 25	1,589,080	(9,996)	(759,083)
Ending balance (in shares) at Sep. 30, 2022	0
Beginning balance (in shares) at Jun. 30, 2022			247,110,000
Beginning balance at Jun. 30, 2022	$ 868,042		$ 25	1,565,197	(8,351)	(688,829)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)			1,375,000
Issuance of common stock upon exercise of stock options	5,127			5,127
Stock-based compensation (in shares)			650,000
Stock-based compensation	19,123			19,123
Issuance of common stock in connection with restricted stock units, net of tax (in shares)			105,000
Issuance of common stock in connection with restricted stock units, net of tax	(367)			(367)
Other comprehensive loss	(1,645)				(1,645)
Net loss	$ (70,254)					(70,254)
Ending balance (in shares) at Sep. 30, 2022	249,239,833		249,240,000
Ending balance at Sep. 30, 2022	$ 820,026		$ 25	$ 1,589,080	$ (9,996)	$ (759,083)

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Convertible Preferred Stock and Stockholders’ Equity (Deficit) (Parenthetical) $ in Thousands	9 Months Ended
	Sep. 30, 2021 USD ($)
Statement of Stockholders' Equity [Abstract]
Stock issuance costs	$ 33,198

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (174,721)	$ (166,513)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	63,561	41,023
Depreciation and amortization expense	12,979	9,059
Impairment of other investments	5,000	0
Change in fair value of success payment liabilities	2,177	19,343
Change in fair value of equity warrant	1,067	199
Non-cash lease expense	(1,104)	1,486
Net amortization and accretion on marketable securities	278	1,434
Loss on property and equipment disposals, net	97	536
Changes in operating assets and liabilities:
Prepaid expenses, other current assets and other assets	(672)	(6,811)
Accounts payable	1,193	(8)
Accrued liabilities and other current liabilities	(5,836)	325
Deferred revenue	(36,299)	(7,697)
Operating lease liabilities, non-current	3,331	10,467
Other non-current liabilities	(339)	4,121
Net cash used in operating activities	(129,288)	(93,036)
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of property and equipment	(19,694)	(55,236)
Purchases of marketable securities	(346,647)	(539,541)
Sales and maturities of marketable securities	308,153	547,066
Net cash used in investing activities	(58,188)	(47,711)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from exercise of stock options	9,252	2,043
Proceeds from employee stock purchase plan	887	0
Taxes paid related to net share settlement of equity awards	(367)	0
Proceeds from initial public offering, net of issuance costs	0	391,802
Net cash provided by financing activities	9,772	393,845
Net (decrease) increase in cash, cash equivalents and restricted cash	(177,704)	253,098
Cash, cash equivalents and restricted cash at beginning of period	294,294	140,872
Cash, cash equivalents and restricted cash at end of period	116,590	393,970
Represented by:
Cash and cash equivalents	116,311	393,504
Restricted cash	279	466
Total	116,590	393,970
SUPPLEMENTAL CASH FLOW INFORMATION
Cash received for amounts related to tenant improvement allowances	3,238	11,063
Cash paid for amounts included in the measurement of lease liabilities	8,136	5,658
Non-cash investing and financing activities:
Purchases of property and equipment included in accounts payable and accrued liabilities	3,563	5,432
Remeasurement of operating lease right-of-use asset for lease modification	29	4,078
Conversion of convertible preferred stock to common stock upon closing of initial public offering	$ 0	$ 1,010,968

Organization

Organization	9 Months Ended
	Sep. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization Lyell Immunopharma, Inc. (the “Company”) was incorporated in Delaware in June 2018. The Company is a T‑cell reprogramming company dedicated to the mastery of T cells to cure patients with solid tumors. The Company is building a multi-modality product pipeline. The Company’s primary activities since incorporation have been to develop T‑cell therapies, perform research and development, enter into strategic collaboration and license arrangements, build manufacturing capabilities, enable manufacturing activities in support of its product candidate development efforts, acquire technology, organize and staff the Company, conduct business planning, establish its intellectual property portfolio, raise capital and provide general and administrative support for these activities. Initial Public Offering

Basis of Presentation and Signi

Basis of Presentation and Significant Accounting Policies	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies	Basis of Presentation and Significant Accounting Policies Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). The unaudited condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary. All significant intercompany transactions and balances are eliminated in consolidation. Certain prior period amounts in the condensed consolidated financial statements and accompanying notes have been reclassified to conform to the current period’s presentation. The condensed consolidated balance sheet as of December 31, 2021 included herein was derived from the audited consolidated financial statements as of that date. Certain information and footnote disclosures typically included in the Company’s audited consolidated financial statements have been condensed or omitted. The accompanying unaudited condensed consolidated financial statements have been prepared on the same basis as the annual consolidated financial statements and reflect, in the opinion of management, all adjustments of a normal and recurring nature that are necessary for the fair presentation of the Company’s financial position, results of operations and cash flows for the periods presented, but are not necessarily indicative of results to be expected for any future annual or interim period. These unaudited condensed consolidated financial statements should be read in conjunction with the Company’s audited financial statements and notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2021. Liquidity and Management’s Plan The Company is currently working on a number of long-term product candidates that involve experimental technologies. The product candidates may require several years and substantial expenditures to complete and ultimately may be unsuccessful. The Company plans to finance operations with available cash resources or from the issuance of equity or debt securities. The Company believes that its available cash, cash equivalents and marketable securities as of September 30, 2022 will be adequate to fund its operations at least through the next 12 months from the date these unaudited condensed consolidated financial statements are issued. Use of Estimates The preparation of the Company’s condensed consolidated financial statements in conformity with GAAP requires management to make judgments, estimates and assumptions that affect reported amounts and related disclosures. Specific accounts that require management estimates include, but are not limited to, stock-based compensation, valuation of success payments, valuation of other investments, revenue recognition and accrued expenses. Management bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. Actual results could differ materially from those estimates. In June 2022, the Company recorded an adjustment to revenue related to a change in estimate in connection with the Collaboration and License Agreement, entered into in 2019 and amended in June 2020 and December 2021 (“GSK Agreement”) with GlaxoSmithKline Intellectual Property (No. 5) Limited and Glaxo Group Limited (together, “GSK”). The Company and GSK mutually agreed to conclude research activities on an undisclosed target for hematological cancers in June 2022. As a result, the Company decreased the related estimated project costs, which resulted in an increase in the measure of proportional cumulative performance. On October 24, 2022, GSK provided notice to the Company of its decision to terminate the GSK Agreement. The termination is effective on December 24, 2022. This adjustment increased revenue by $35.3 million, decreased net loss by $35.3 million and resulted in a $0.14 reduction in the Company’s basic and diluted net loss per common share for the nine months ended September 30, 2022. Concentrations of Credit Risk and Off-balance Sheet Risk The Company maintains its cash, cash equivalents and restricted cash with high quality, accredited financial institutions. These amounts, at times, may exceed federally insured limits. The Company also makes short-term investments in money market funds, U.S. Treasury securities, U.S. government agency securities and corporate debt securities, which can be subject to certain credit risk. However, the Company mitigates the risks by investing in high-grade instruments, limiting exposure to any one issuer or type of investment and monitoring the ongoing creditworthiness of the financial institutions and issuers. The Company has not experienced any credit losses in such accounts and does not believe it is exposed to significant risk on these funds. The Company has no off-balance sheet concentrations of credit risk, such as foreign currency exchange contracts, option contracts or other hedging arrangements. Significant Accounting Policies There have been no material changes to the significant accounting policies from the Annual Report on Form 10-K for the year ended December 31, 2021. Recently Adopted Accounting Pronouncements None.

License, Collaboration, and Suc

License, Collaboration, and Success Payment Agreements	9 Months Ended
	Sep. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
License, Collaboration, and Success Payment Agreements	License, Collaboration and Success Payment Agreements Fred Hutch License Agreement - In 2018, the Company entered into a license agreement with Fred Hutchinson Cancer Research Center (“Fred Hutch”) that grants the Company an exclusive, worldwide, sublicensable license under certain patent rights and a non-exclusive, worldwide, sublicensable license for certain technology, to research, develop, manufacture, improve and commercialize products and processes covered by such patent rights or incorporating such technology for all therapeutic uses for the treatment of human cancer. The Company is also required to pay Fred Hutch annual license maintenance payments of $50,000 on the second anniversary of the effective date, and each anniversary of the effective date thereafter until the first commercial sale of a licensed product. Collaboration - In 2018, the Company entered into a research and collaboration agreement with Fred Hutch (“Fred Hutch Collaboration Agreement”), focused on research and development of cancer immunotherapy products. The Company funded aggregate research performed by Fred Hutch of $12.0 million under the Fred Hutch Collaboration Agreement and the research is conducted in accordance with a research plan and budget approved by the parties. The Fred Hutch Collaboration Agreement has a six-year term. During 2021, one of the research plans on which the success payment service term is based was extended from January 31, 2022 to December 31, 2022. The Company incurred $0.4 million and $1.1 million in expense in connection with the Fred Hutch Collaboration Agreement for the three months ended September 30, 2022 and 2021, respectively, and $1.4 million and $3.1 million for the nine months ended September 30, 2022 and 2021, respectively. Success Payments - In 2018, the Company granted Fred Hutch rights to certain success payments, pursuant to the terms of the Fred Hutch Collaboration Agreement. The potential payments for the Fred Hutch success payments are based on multiples of increased value ranging from 10x to 50x based on a comparison of the estimated per share fair value of the Series A convertible preferred stock, or any security into which such stock has been converted or for which it has been exchanged, relative to its original $1.83 per share issuance price. Upon the closing of the IPO, all shares of Series A convertible preferred stock then outstanding converted into an equal number of shares of common stock. The aggregate success payments to Fred Hutch are not to exceed $200.0 million, which would only occur upon a 50 times increase in value. Each threshold is associated with a success payment, ascending from $10.0 million at $18.29 per share to $200.0 million at $91.44 per share, payable if such threshold is reached during the measurement period. Any previous success payments made are credited against the success payment owed as of any valuation date, such that Fred Hutch does not receive multiple success payments in connection with the same threshold. The term of the success payment agreement ends on the earlier to occur of (i) the nine-year anniversary of the date of the agreement and (ii) a change in control transaction. The following table summarizes the aggregate potential success payments, which are payable to Fred Hutch in cash or cash equivalents, or at the Company’s discretion, publicly-tradeable shares of the Company’s common stock: Multiple of initial equity value at issuance 10x 20x 30x 40x 50x Per share common stock price required for payment $ 18.29 $ 36.58 $ 54.86 $ 73.15 $ 91.44 Aggregate success payment(s) (in millions) $ 10 $ 40 $ 90 $ 140 $ 200 The success payments will be owed if the per share fair value of the Company’s common stock on the contractually specified valuation measurement dates during the term of the success payment agreement equals or exceeds the above outlined multiples. The valuation measurement dates are triggered by the following events: the one-year anniversary of the Company’s IPO and each two-year anniversary of the Company’s IPO thereafter, the closing of a change in control transaction and the last day of the term of the success payment agreement, unless the term has ended due to the closing of a change of control transaction. As of September 30, 2022, no success payments have been incurred as the per share fair value of the Company’s common stock was below the price required for payment. The estimated fair values of the success payments to Fred Hutch as of September 30, 2022 and December 31, 2021 were $7.7 million and $8.5 million, respectively. The success payment liability is estimated at the fair value at inception and at each subsequent reporting period and the expense is accreted over the service period of the Fred Hutch Collaboration Agreement. The success payment liability was $7.2 million and $6.4 million as of September 30, 2022 and December 31, 2021, respectively. With respect to the Fred Hutch Collaboration Agreement success payment obligations, the Company recognized expense of $1.4 million and a decrease in success payment expense of $(0.8) million for the three months ended September 30, 2022 and 2021, respectively, and success payment expense of $0.8 million and $14.1 million for the nine months ended September 30, 2022 and 2021, respectively. Stanford License Agreement - In 2019, the Company entered into a license agreement with The Board of Trustees of the Leland Stanford Junior University (“Stanford”) to license specified patent rights. The Company is also required to pay Stanford annual license maintenance payments of $50,000 on the second anniversary of the effective date, and each anniversary of the effective date thereafter until the date of the first commercial sale of a licensed product. Milestone payments to Stanford of up to a maximum of $3.7 million per target are payable upon achievement of certain specified clinical and regulatory milestones. The Company is also obligated to pay Stanford $2.5 million collectively for all licensed products upon the achievement of a certain commercial milestone. Additionally, low single‑digit tiered royalties based on annual net sales of the licensed products are payable to Stanford. Collaboration Agreement - In October 2020, the Company entered into a research and collaboration agreement with Stanford (“Stanford Collaboration Agreement”), focused on research and development of cellular immunotherapy products. The Stanford Collaboration Agreement has a four-year term. The Company is committed to fund aggregate research performed by Stanford of $12.0 million under the Stanford Collaboration Agreement, and the research will be conducted in accordance with a research plan and budget approved by the parties. The Company incurred $0.8 million in expense in connection with the Stanford Collaboration Agreement for each of the three months ended September 30, 2022 and 2021, and $2.3 million for each of the nine months ended September 30, 2022 and 2021. Success Payments - In October 2020, the Company granted Stanford rights to certain success payments, pursuant to the terms of the Stanford Collaboration Agreement. The potential payments for the Stanford Collaboration Agreement success payments are based on multiples of increased value ranging from 10x to 50x based on a comparison of the estimated per share fair value of the Series A convertible preferred stock, or any security into which such stock has been converted or for which it has been exchanged, relative to its original $1.83 per share issuance price. At the closing of the IPO, all shares of Series A convertible preferred stock then outstanding converted into an equal number of shares of common stock. The aggregate success payments to Stanford are not to exceed $200.0 million, which would only occur upon a 50 times increase in value. Each threshold is associated with a success payment, ascending from $10.0 million at $18.29 per share to $200.0 million at $91.44 per share, payable if such threshold is reached during the measurement period. Any previous success payments made are credited against the success payment owed as of any valuation date, so that Stanford does not receive multiple success payments in connection with the same threshold. The term of each success payment agreement ends on the earlier to occur of (i) the nine-year anniversary of the date of the agreement and (ii) a change in control transaction. The following table summarizes the aggregate potential success payments, which are payable to Stanford in cash or cash equivalents or, at the Company’s discretion, publicly-tradeable shares of the Company’s common stock: Multiple of initial equity value at issuance 10x 20x 30x 40x 50x Per share common stock price required for payment $ 18.29 $ 36.58 $ 54.86 $ 73.15 $ 91.44 Aggregate success payment(s) (in millions) $ 10 $ 40 $ 90 $ 140 $ 200 The success payments will be owed if the per share fair value of the Company’s common stock on the contractually specified valuation measurement dates during the term of the success payment agreement equals or exceeds the above outlined multiples. The valuation measurement dates are triggered by the following events: the one-year anniversary of the Company’s IPO and each two-year anniversary of the Company’s IPO thereafter, the closing of a change in control transaction and the last day of the term of the success payment agreement, unless the term has ended due to the closing of a change of control transaction. As of September 30, 2022, no success payments have been incurred as the per share fair value of the Company’s common stock was below the price required for payment. The estimated fair value of the success payments to Stanford as of September 30, 2022 and December 31, 2021 was $8.9 million and $9.9 million, respectively. The success payment liability is estimated at the fair value at inception and at each subsequent reporting period and the expense is accreted over the service period of the Stanford Collaboration Agreement. The success payment liability was $4.5 million and $3.1 million as of September 30, 2022 and December 31, 2021, respectively. With respect to the Stanford Collaboration Agreement success payment obligations, the Company recognized expense of $1.0 million for each of the three months ended September 30, 2022 and 2021, respectively, and $1.4 million and $5.2 million for the nine months ended September 30, 2022 and 2021, respectively. GSK In 2019, the Company entered into the GSK Agreement with GSK for potential T-cell therapies that apply the Company’s platform technologies and cell therapy innovations with T-cell receptors (“TCRs”) or chimeric antigen receptors (“CARs”) under distinct collaboration programs. The GSK Agreement defined two initial collaboration targets and allows GSK to nominate seven additional targets through July 2024. The Company is expected to perform research and development services for each selected target up until a defined point (the “GSK Option Point”), at which time GSK will decide whether or not to exercise an option to obtain a license from the Company (“License Option”) and take over the future development and commercialization. Selected targets may be developed as either a Proof of Concept (“PoC”) Development Program or Component Development Program. For a PoC Development Program, the Company is expected to conduct both preclinical and clinical development for the target and present clinical trial data to GSK in connection with their evaluation of whether to exercise the License Option. For a Component Development Program, the Company is obligated to perform preclinical studies only. Along with the research activities, the Company appointed three representatives to the joint steering committee (“JSC”) and is responsible for the manufacture of all compounds and products necessary for its research and development activities. The Company received a non-refundable upfront payment of $45.0 million under the GSK Agreement. In addition to the upfront payment, the Company is eligible to receive up to two one-time payments, totaling up to approximately $200.0 million in aggregate for technology validation of the Company’s cell therapy innovations. For each cell therapy target for which there has been a joint collaboration program, the Company is also entitled to receive up to approximately $400.0 million in aggregate in development and sales milestones if the target is already within GSK’s pipeline and meets certain criteria, up to approximately $900.0 million in aggregate in development and sales milestones for all other targets, and tiered royalties on a per-product basis ranging from low to high single digits for targets that are already within GSK’s pipeline and meet certain criteria, or from high single digit to low teens for all other targets. Milestones are paid once per target, even if there is more than one of the Company’s innovations applied to a T-cell therapy directed to that target. Any amounts received from GSK are generally non-refundable unless the Company terminates a collaboration target for safety or feasibility reasons and the funding received from GSK exceeds the costs incurred for the terminated target. In connection with the GSK Agreement, in May 2019, the Company also entered into a Stock Purchase Agreement with GSK (“GSK Stock Purchase Agreement”), pursuant to which the Company agreed to sell 30,253,189 shares of Series AA convertible preferred stock at a price of $6.78 per share, which was above the issuance date estimated fair value of $4.84 per share. The difference between the per share values resulted in $58.6 million additional deemed consideration, bringing the total upfront payment of the GSK Agreement to $103.6 million. On October 24, 2022, GSK provided notice to the Company of its decision to terminate the GSK Agreement. The termination is effective on December 24, 2022. See Note 14, Subsequent Events , for additional details regarding termination of the GSK Agreement. Research and Development Services The GSK Agreement was deemed to be within the scope of Accounting Standards Codification (“ASC”) 606, Revenue from Contracts with Customers , because GSK engaged the Company to initially provide research and development services, which are outputs of its ongoing activities, in exchange for consideration. The Company identified the following two distinct performance obligations: (i) research and development services related to the two initial collaboration targets, inclusive of the JSC participation and the manufacture of compounds necessary for providing the research and development services and (ii) a material right for GSK to nominate seven additional collaboration targets for which the Company will perform research and development services until the GSK Option Point. To allocate revenue among the performance obligations, the Company determined standalone selling prices (“SSP”) of each obligation. For the research and development services, the SSP was calculated using a cost-plus margin approach. For the material right, SSP was calculated by reference to the underlying research and development services expected to be provided and the corresponding expected consideration. All amounts included in the transaction price are allocated to performance obligations proportionate to their SSPs. As of December 31, 2020, the transaction price was deemed to be $103.6 million, consisting of the upfront payment of $45.0 million under the GSK Agreement and the $58.6 million allocated from the GSK Stock Purchase Agreement. Other than the upfront payment and the amounts allocated from the GSK Stock Purchase Agreement, all other contingent consideration that may be earned under the GSK Agreement is subject to uncertainties including but not limited to additional target selections, research and investigational new drug enabling studies, initiation of clinical trials and other related achievements. Consequently, the transaction price currently does not include any such contingent consideration that, if included, could result in a probable significant reversal of cumulative revenue when related uncertainties become resolved. The Company re-evaluates the transaction price at each reporting period. If and when contingent consideration is included in the transaction price, it will be allocated to the two performance obligations proportionate to their SSPs and a cumulative catch up in revenue will be recorded for the portion of the services already completed. The remaining amounts will be deferred and recognized as the services are rendered. The research and development services are transferred as the services are performed, with cost used as the measure of progress compared to the total estimated cost to complete. Incurred cost represents work performed, which corresponds with, and thereby best depicts, the transfer of control to the customer. The determination of the percentage of completion requires the Company to estimate the costs to complete the project. The Company makes a detailed estimate of the costs to complete, which is reassessed every reporting period based on the latest project plan and discussions with project teams. If a change in facts or circumstances occurs, the estimate will be adjusted, and the revenue will be recognized based on the revised estimate. The difference between the cumulative revenue recognized based on the previous estimate and the revenue recognized based on the revised estimate would be recognized as an adjustment to revenue in the period in which the change in estimate occurs. In June 2022, the Company recorded an adjustment to revenue related to a change in estimate in connection with the GSK Agreement due to GSK and the Company mutually agreeing to conclude research activities on an undisclosed target for hematological cancers. The change in estimate decreased the related estimated project costs, which resulted in an increase in the measure of proportional cumulative performance. This adjustment increased revenue by $35.3 million, decreased net loss by $35.3 million and resulted in a $0.14 reduction in the Company’s basic and diluted net loss per common share for the nine months ended September 30, 2022. The Company recognized revenue related to the research and development services related to the two initial targets of zero and $2.6 million for the three months ended September 30, 2022 and 2021, respectively, and $36.3 million and $7.7 million for the nine months ended September 30, 2022 and 2021, respectively. As of September 30, 2022 and December 31, 2021, the Company had deferred revenue of $48.4 million and $84.7 million, respectively, related to this agreement. In light of the termination of the GSK Agreement, effective December 24, 2022, the Company expects all research and development activities related to the collaboration thereunder to cease after such date. See Note 14, Subsequent Events , for additional details regarding termination of the GSK Agreement. Exercise of the License Option In April 2021, GSK exercised the License Option on LYL331 (NY-ESO-1 TCR with c-Jun), a Component Development Program, and agreed to assume sole responsibility for future development and commercialization of the program at its own cost and expense. The Company is entitled to the remaining development and sales milestones up to an aggregate of approximately $400.0 million as well as the tiered royalties on future sales of all such products covered by the license granted pursuant to the License Option. The exercise of the License Option was accounted for as a separate license contract for revenue recognition purposes. The Company identified one performance obligation, which was the license delivered to GSK upon the exercise of the License Option and transfer of information and data associated with the license. The Company concluded that the development milestone payments are solely dependent on GSK’s performance and achievement of the specified events and are deemed to be not probable until such development milestones are achieved. Therefore, the remaining development milestones are fully constrained and excluded from the transaction price until the respective milestone is achieved. The Company also concluded that sales milestones and royalties relate predominantly to the license granted to GSK. Therefore, they also have been excluded from the transaction price and will be recognized when the related sales occur. At the end of each reporting period, the Company updates its assessment of whether an estimate of variable consideration is constrained and updates the estimated transaction price accordingly. As of September 30, 2022, there were no contract assets or contract liabilities related to the license contract. None of the costs to obtain or fulfill the contract were capitalized. No license revenue was recognized for the three and nine months ended September 30, 2022 and 2021. As discussed above, the GSK Agreement will terminate in December 2022, in connection with which the Company’s license to GSK also terminates. See Note 14, Subsequent Events , for additional details regarding termination of the GSK Agreement. PACT In June 2020, the Company entered into a commitment agreement (“PACT Commitment Agreement”) with PACT Pharma, Inc. (“PACT”) to jointly develop and test a next generation personalized anti-cancer T-cell therapy against solid tumors. The Company paid PACT an upfront non-refundable payment of $50.0 million upon execution of the PACT Commitment Agreement. In November 2020, the parties agreed to suspend research and development activity under the PACT Commitment Agreement, and neither party would be required to conduct any further work under the development plan (including manufacturing development) nor incur any financial obligations (including milestone payments) that might otherwise arise, for as long as the parties continued to negotiate in good faith to resolve the issues that have arisen between them relating to the PACT Commitment Agreement. In June 2020 in connection with the entry into the PACT Commitment Agreement, the Company also entered into a stock purchase agreement with PACT (“PACT SPA”), pursuant to which the Company purchased 17,806,901 shares of PACT Series C-1 convertible preferred stock at a purchase price of $2.81 per share. As of the purchase date, the estimated fair value of the Series C-1 convertible preferred stock was $2.05 per share, and the difference between the estimated fair value of the preferred stock as of the purchase date and the purchase price of $13.6 million was deemed to be additional consideration for the PACT Commitment Agreement and recognized as research and development expense. As a result, the total upfront payment paid in connection with the PACT Commitment Agreement was $63.6 million and was included in research and development expense. The remaining $36.4 million associated with the PACT Series C-1 convertible preferred stock was recorded in other investments. In the fourth quarter of 2021, the Company fully impaired the remaining balance of $36.4 million. See Note 5, Other Investments , for additional details regarding the PACT investment impairment. In February 2021, the Company filed a demand for arbitration seeking, among other things, rescission of the PACT Commitment Agreement and the PACT SPA and recovery of the consideration paid thereunder. Arbitration hearings occurred in March and April 2022. In October 2022, the Company entered into a settlement agreement with PACT to resolve their outstanding legal dispute, which resulted in the Company obtaining ownership of approximately 80% of PACT’s fully diluted shares. See Note 14, Subsequent Events , for additional details regarding the PACT settlement agreement.

Cash Equivalents and Marketable

Cash Equivalents and Marketable Securities	9 Months Ended
	Sep. 30, 2022
Cash and Cash Equivalents [Abstract]
Cash Equivalents and Marketable Securities	Cash Equivalents and Marketable Securities The fair value and amortized cost of cash equivalents and marketable securities by major security type are as follows (in thousands): September 30, 2022 Amortized Cost Gross Gross Unrealized Losses Fair Value Money market funds $ 42,608 $ — $ — $ 42,608 U.S. Treasury securities 313,281 — (6,972) 306,309 U.S. government agency securities 147,357 2 (1,716) 145,643 Corporate debt securities 235,749 1 (1,311) 234,439 Total cash equivalents and marketable securities $ 738,995 $ 3 $ (9,999) $ 728,999 Classified as: Fair Value Cash equivalents $ 94,659 Marketable securities 531,821 Marketable securities, non-current 102,519 Total cash equivalents and marketable securities $ 728,999 December 31, 2021 Amortized Cost Gross Gross Unrealized Losses Fair Value Money market funds $ 206,245 $ — $ — $ 206,245 U.S. Treasury securities 290,909 2 (1,205) 289,706 U.S. government agency securities 93,864 2 (240) 93,626 Corporate debt securities 285,338 — (182) 285,156 Total cash equivalents and marketable securities $ 876,356 $ 4 $ (1,627) $ 874,733 Classified as: Fair Value Cash equivalents $ 270,236 Marketable securities 320,966 Marketable securities, non-current 283,531 Total cash equivalents and marketable securities $ 874,733 The fair value of securities held by the Company in an unrealized continuous loss position for less than 12 months were $507.3 million and $602.9 million as of September 30, 2022 and December 31, 2021, respectively. The fair value of securities held by the Company in an unrealized continuous loss position for greater than 12 months were $126.5 million and zero as of September 30, 2022 and December 31, 2021, respectively. As of September 30, 2022 and December 31, 2021, all of the Company’s marketable securities had a maturity date of two years or less, were available for use and were classified as available-for-sale. The Company does not intend to sell these securities nor does the Company believe that it will be required to sell these securities before recovery of their amortized cost basis. The Company determined that there was no material change in the credit risk of the above investments during the three and nine months ended September 30, 2022 and 2021. As such, an allowance for credit losses has not been recognized. Gross realized gains and losses were de minimis for the three and nine months ended September 30, 2022 and 2021 and as a result, amounts reclassified out of accumulated other comprehensive loss for the three and nine months ended September 30, 2022 and 2021 were also de minimis . See Note 6, Fair Value Measurements, for additional information regarding cash equivalents and marketable securities.

Other Investments

Other Investments	9 Months Ended
	Sep. 30, 2022
Investments, All Other Investments [Abstract]
Other Investments	Other InvestmentsFrom time to time, the Company makes minority ownership strategic investments. As of September 30, 2022 and December 31, 2021, the aggregate carrying amounts of the Company’s strategic investments in non-publicly traded companies were $42.0 million and $47.0 million, respectively. These investments were measured at initial cost, minus impairment, if any, and plus or minus changes resulting from observable price changes in orderly transactions for an identical or similar investment of the same issuer. In connection with the preparation of the financial statements for the third quarter ended September 30, 2022, the Company performed a qualitative assessment of potential indicators of impairment and determined that indicators existed for one of the Company’s other investments with a carrying amount of $5.0 million. While there was no single event or factor, the Company considered the underlying company’s operating cash flow requirements over the next year and liquid asset balances to fund those requirements and the underlying company’s inability to raise funds as indicators of impairment. Due to these indicators, the Company assessed the valuation of the investment as of September 30, 2022 and determined the fair value to be negligible and the impairment to be other-than-temporary in nature. As a result, the Company recorded a $5.0 million impairment expense for the investment for the third quarter ended September 30, 2022, which was recorded within impairment of other investments on the Condensed Consolidated Statement of Operations and Comprehensive Loss and as a reduction to the investment balance within other investments on the Condensed Consolidated Balance Sheet. There were no additional adjustments recorded to the carrying amount for other investments for the three and nine months ended September 30, 2022 and 2021. In connection with the preparation of the financial statements for 2021, the Company performed a qualitative assessment of potential indicators of impairment and determined that indicators existed for its $36.4 million investment in PACT Series C-1 convertible preferred stock. While there was no single event or factor, the Company considered PACT’s operating cash flow requirements over the next year and liquid asset balances to fund those requirements and PACT’s inability to raise funds as indicators of impairment. Due to these indicators, the Company assessed the valuation of the investment in PACT as of December 31, 2021 and determined the fair value to be negligible and the impairment to be other-than-temporary in nature. As a result, the Company recorded a $36.4 million impairment expense for the PACT investment in the fourth quarter of 2021, which was recorded within impairment of other investments on the Consolidated Statement of Operations and Comprehensive Loss and as a reduction to the investment balance within other investments on the Consolidated Balance Sheet. In November 2020, the Company made a strategic equity investment of $13.0 million in Outpace Bio, Inc. (“Outpace”), a privately-held company, which represented a minority ownership interest at the time of the strategic investment. Outpace is engaged in the research and development of protein and cell technology platforms and has financed its activities via issuances of preferred stock. The Company determined that Outpace is a variable interest entity (“VIE”) and the at-risk equity holders, as a group, lack the characteristics of a controlling financial interest. The Company does not have majority voting rights, representation on Outpace’s board of directors or the power to direct the activities of this entity, and therefore it is not the primary beneficiary. As of both September 30, 2022 and December 31, 2021, the carrying value of the Company’s investment in Outpace was $13.0 million, which is recorded in other investments.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The following table sets forth the fair value of the Company’s financial assets and liabilities measured at fair value on a recurring basis based on the three-tier fair value hierarchy (in thousands): September 30, 2022 Level 1 Level 2 Level 3 Total Financial assets: Money market funds $ 42,608 $ — $ — $ 42,608 U.S. Treasury securities — 306,309 — 306,309 U.S. government agency securities — 145,643 — 145,643 Corporate debt securities — 234,439 — 234,439 Total financial assets $ 42,608 $ 686,391 $ — $ 728,999 Financial liabilities: Success payment liabilities $ — $ — $ 11,663 $ 11,663 Total financial liabilities $ — $ — $ 11,663 $ 11,663 December 31, 2021 Level 1 Level 2 Level 3 Total Financial assets: Money market funds $ 206,245 $ — $ — $ 206,245 U.S. Treasury securities — 289,706 — 289,706 U.S. government agency securities — 93,626 — 93,626 Corporate debt securities — 285,156 — 285,156 Equity warrant investment — — 1,067 1,067 Total financial assets $ 206,245 $ 668,488 $ 1,067 $ 875,800 Financial liabilities: Success payment liabilities $ — $ — $ 9,486 $ 9,486 Total financial liabilities $ — $ — $ 9,486 $ 9,486 The Company measures the fair value of money market funds based on quoted prices in active markets for identical assets or liabilities. The Level 2 marketable securities include U.S. Treasury securities, U.S. government agency securities and corporate debt securities. The Company’s Level 2 securities are valued using third-party pricing sources. The pricing services applied industry standard valuation models. Inputs utilized include market pricing based on real-time trade data for the same or similar securities and other significant inputs derived from or corroborated by observable market data. The Level 3 financial instruments include an equity warrant investment and the success payment liabilities. For the quarter ended September 30, 2022, in conjunction with the impairment of one of the Company's other investments, the associated equity warrant investment’s fair value was determined to be negligible. For the quarter ended September 30, 2022, the Company reduced the equity warrant investment’s fair value from $1.1 million to zero. See Note 5, Other Investments, for additional details regarding the impairment of the other investment. The Company’s Level 3 financial instruments are valued using valuation models which include the Black-Scholes model for valuing the equity warrant investment and a Monte Carlo simulation for the success payment liabilities. To determine the estimated fair value of the success payment liabilities, the Company uses a Monte Carlo simulation methodology that models the future movement of stock prices based on several key variables combined with empirical knowledge of the process governing the behavior of the stock price. The following variables were incorporated in the estimated fair value of the success payment liabilities: fair value of the Company’s common stock, expected volatility, the risk-free interest rate and the estimated number and timing of valuation measurement dates on the basis of which payments may be triggered. The computation of expected volatility was estimated based on available information about the historical volatility of stocks of similar publicly traded companies for a period matching the expected term assumption. The following assumptions were incorporated into the calculation of the estimated fair value of the Fred Hutch success payment liability: September 30, December 31, Fair value of common stock $ 7.33 $ 7.74 Risk-free interest rate 3.66% - 4.26% 0.19% - 1.88% Expected volatility 80.0 % 75.0 % Expected term (in years) 0.71 - 5.22 0.46 - 5.97 The following assumptions were incorporated into the calculation of the estimated fair value of the Stanford success payment liability: September 30, December 31, Fair value of common stock $ 7.33 $ 7.74 Risk-free interest rate 3.66% - 4.26% 0.19% - 1.88% Expected volatility 80.0 % 75.0 % Expected term (in years) 0.71 - 7.00 0.46 - 7.75 The Company utilizes estimates and assumptions in determining the estimated success payment liabilities and associated expense. A small change in the valuation of the Company’s common stock may have a relatively large change in the estimated fair value of the success payment liability and associated expense. The following table sets forth a summary of the changes in the fair value of the Company’s Level 3 financial assets and liabilities (in thousands): Equity Warrant Success Payment Balance at December 31, 2021 $ 1,067 $ 9,486 Change in fair value (1) (1,067) 2,177 Balance at September 30, 2022 $ — $ 11,663 (1) The change in fair value associated with the equity warrant investment held is recorded in other (expense) income, net and the change in fair value associated with success payment liabilities is recorded in research and development expense.

Leases

Leases	9 Months Ended
	Sep. 30, 2022
Leases [Abstract]
Leases	Leases The Company’s lease portfolio is comprised of operating leases for laboratory, office and manufacturing facilities located in South San Francisco, California, and Seattle and Bothell, Washington with contractual periods expiring between December 2028 and March 2031. In addition to minimum rent, the leases require payment of real estate taxes, insurance, common area maintenance charges and other executory costs. These additional charges are considered variable lease costs and are recognized in the period in which the costs are incurred. The following table summarizes the Company’s future minimum operating lease commitments, including expected lease incentives to be received, as of September 30, 2022 (in thousands): Year Ending December 31: 2022 (remaining three months) $ 1,822 2023 11,018 2024 11,347 2025 11,859 2026 12,209 Thereafter 48,094 Total undiscounted lease payments 96,349 Less: imputed interest (27,351) Less: tenant improvement allowances (1,523) Total operating lease liabilities $ 67,475 Reported as of September 30, 2022: Short-term portion of lease liabilities (included in accrued liabilities and other current liabilities) $ 2,839 Operating lease liabilities, non-current 64,636 Total $ 67,475 The operating lease costs for all operating leases were $2.3 million and $2.4 million for the three months ended September 30, 2022 and 2021, respectively, and $7.0 million and $7.1 million for the nine months ended September 30, 2022 and 2021, respectively. The operating lease costs and total commitments for short-term leases were de minimis for the three and nine months ended September 30, 2022 and 2021. Variable lease costs for operating leases were $1.3 million and $1.4 million for the three months ended September 30, 2022 and 2021, respectively, and $3.8 million and $3.7 million for the nine months ended September 30, 2022 and 2021, respectively. The weighted-average remaining lease terms for operating leases were 8.0 and 8.8 years as of September 30, 2022 and December 31, 2021, respectively. The weighted-average discount rates for operating leases were 8.5% and 8.4% as of September 30, 2022 and December 31, 2021, respectively. In May 2021, the Company entered into a sublease, whereby the Company agreed to sublease approximately 11,000 square feet of its space in South San Francisco, California currently leased by the Company. The sublease is classified as an operating lease and will expire in March 2031. The Company recognized sublease income for this sublease of $0.2 million and $0.1 million for the three months ended September 30, 2022 and 2021, respectively, and $0.6 million and $0.1 million for the nine months ended September 30, 2022 and 2021, respectively. In September 2021, the Company entered into a sublease with Sonoma Biotherapeutics, Inc. (“Sonoma”), a related party, whereby the Company agreed to sublease approximately 18,000 square feet of space in South San Francisco, California currently leased by the Company. See Note 13, Related-Party Transactions. As a part of the sublease, in September 2021, the Company received a $4.6 million tenant improvement contribution payment, which is recognized over the term of the sublease. The sublease is classified as an operating lease and will expire in March 2031. The Company recognized Sonoma sublease income of $0.5 million and $0.2 million for the three months ended September 30, 2022 and 2021, respectively, and $1.4 million and $0.2 million for the nine months ended September 30, 2022 and 2021, respectively. The Company's sublease income is recognized within other operating income, net in the condensed consolidated statements of operations and comprehensive loss.
Leases	Leases The Company’s lease portfolio is comprised of operating leases for laboratory, office and manufacturing facilities located in South San Francisco, California, and Seattle and Bothell, Washington with contractual periods expiring between December 2028 and March 2031. In addition to minimum rent, the leases require payment of real estate taxes, insurance, common area maintenance charges and other executory costs. These additional charges are considered variable lease costs and are recognized in the period in which the costs are incurred. The following table summarizes the Company’s future minimum operating lease commitments, including expected lease incentives to be received, as of September 30, 2022 (in thousands): Year Ending December 31: 2022 (remaining three months) $ 1,822 2023 11,018 2024 11,347 2025 11,859 2026 12,209 Thereafter 48,094 Total undiscounted lease payments 96,349 Less: imputed interest (27,351) Less: tenant improvement allowances (1,523) Total operating lease liabilities $ 67,475 Reported as of September 30, 2022: Short-term portion of lease liabilities (included in accrued liabilities and other current liabilities) $ 2,839 Operating lease liabilities, non-current 64,636 Total $ 67,475 The operating lease costs for all operating leases were $2.3 million and $2.4 million for the three months ended September 30, 2022 and 2021, respectively, and $7.0 million and $7.1 million for the nine months ended September 30, 2022 and 2021, respectively. The operating lease costs and total commitments for short-term leases were de minimis for the three and nine months ended September 30, 2022 and 2021. Variable lease costs for operating leases were $1.3 million and $1.4 million for the three months ended September 30, 2022 and 2021, respectively, and $3.8 million and $3.7 million for the nine months ended September 30, 2022 and 2021, respectively. The weighted-average remaining lease terms for operating leases were 8.0 and 8.8 years as of September 30, 2022 and December 31, 2021, respectively. The weighted-average discount rates for operating leases were 8.5% and 8.4% as of September 30, 2022 and December 31, 2021, respectively. In May 2021, the Company entered into a sublease, whereby the Company agreed to sublease approximately 11,000 square feet of its space in South San Francisco, California currently leased by the Company. The sublease is classified as an operating lease and will expire in March 2031. The Company recognized sublease income for this sublease of $0.2 million and $0.1 million for the three months ended September 30, 2022 and 2021, respectively, and $0.6 million and $0.1 million for the nine months ended September 30, 2022 and 2021, respectively. In September 2021, the Company entered into a sublease with Sonoma Biotherapeutics, Inc. (“Sonoma”), a related party, whereby the Company agreed to sublease approximately 18,000 square feet of space in South San Francisco, California currently leased by the Company. See Note 13, Related-Party Transactions. As a part of the sublease, in September 2021, the Company received a $4.6 million tenant improvement contribution payment, which is recognized over the term of the sublease. The sublease is classified as an operating lease and will expire in March 2031. The Company recognized Sonoma sublease income of $0.5 million and $0.2 million for the three months ended September 30, 2022 and 2021, respectively, and $1.4 million and $0.2 million for the nine months ended September 30, 2022 and 2021, respectively. The Company's sublease income is recognized within other operating income, net in the condensed consolidated statements of operations and comprehensive loss.

Convertible Preferred Stock

Convertible Preferred Stock	9 Months Ended
	Sep. 30, 2022
Equity [Abstract]
Convertible Preferred Stock	Convertible Preferred StockUpon the closing of the IPO, 194,474,431 shares of convertible preferred stock then outstanding converted into an equal number of shares of common stock. As of September 30, 2022 and December 31, 2021, no shares of convertible preferred stock were outstanding.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2022
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity Preferred Stock The Company is authorized to issue 10.0 million shares of preferred stock with a par value of $0.0001 per share. As of September 30, 2022 and December 31, 2021, no shares of preferred stock were outstanding. Common Stock The Company is authorized to issue 500.0 million shares of common stock with a par value of $0.0001 per share. As of September 30, 2022 and December 31, 2021, there were 249,239,833 shares and 242,738,350 shares of the Company’s common stock outstanding, respectively, excluding zero shares and 2,600,002 shares, respectively, of restricted stock awards (“RSAs”) outstanding that are subject to vesting requirements. On August 4, 2022, the Company entered into an Equity Distribution Agreement with Goldman Sachs & Co. LLC (“Goldman Sachs”) and BofA Securities, Inc. (“BofA”, and together with Goldman Sachs, “the Agents”) with respect to an at-the-market offering program (the “Equity Distribution Agreement”). In accordance with the terms of the Equity Distribution Agreement, the Company may offer and sell from time to time through the Agents shares of the Company’s common stock having an aggregate offering amount of up to $200.0 million (“the Placement Shares”). Sales of the Placement Shares, if any, will be made at prevailing market prices on Nasdaq at the time of sale, or as otherwise agreed with the Agents, by any method permitted by law deemed to be an “at-the-market offering” as defined in Rule 415 of the Securities Act of 1933, as amended. The Company will pay commissions to the Agents of up to 3.0% of the gross proceeds of the sale of the Placement Shares sold under the Equity Distribution Agreement and reimburse the Agents for certain expenses. Neither the Company nor the Agents are obligated to sell any shares and, to date, the Company has not made any sales under the Equity Distribution Agreement.

Stock-based Compensation

Stock-based Compensation	9 Months Ended
	Sep. 30, 2022
Share-based Payment Arrangement [Abstract]
Stock-based Compensation	Stock-based Compensation 2021 Equity Incentive Plan In June 2021, the Company adopted the 2021 Equity Incentive Plan (“2021 Plan”), which on the date of the underwriting agreement related to the Company’s IPO became effective with an initial reserve of 26,662,087 shares, plus any shares subject to outstanding awards granted under the 2018 Equity Incentive Plan (“2018 Plan”) that, on or after the effectiveness of the 2021 Plan, terminate or expire before exercise or settlement, are not issued because the award is settled in cash, are forfeited because of the failure to vest, or are reacquired or withheld (or not issued) to satisfy a tax withholding obligation or the purchase or exercise price. In addition, the number of shares reserved for issuance under the 2021 Plan automatically increases on January 1 of each year for a period of ten years, beginning on January 1, 2022 and continuing through January 1, 2031, in an amount equal to (1) 5% of the total number of shares of the Company’s common stock outstanding on December 31 of the immediately preceding year, or (2) a lesser number of shares determined by the Company’s board of directors no later than December 31 of the immediately preceding year. On January 1, 2022, the Company reserved an additional 12,266,917 shares of common stock for issuance under the 2021 Plan representing 5% of the total common shares outstanding as of December 31, 2021. On March 29, 2022, the Company filed with the Securities and Exchange Commission (“SEC”) a Form S-8 registering the additional shares. Under the 2021 Plan, the Company may grant incentive stock options, non-statutory stock options, RSAs, restricted stock units (“RSUs”), stock appreciation rights, performance awards and other stock-based awards. Terms of stock awards, including vesting requirements, are determined by the Company’s board of directors or by a committee authorized by the Company’s board of directors, subject to provisions of the 2021 Plan. The term of any stock option granted under the 2021 Plan cannot exceed ten years. Generally, awards granted by the Company vest over four years but may be granted with different vesting terms. In conjunction with adopting the 2021 Plan, the Company discontinued the 2018 Plan with respect to new equity awards. As of September 30, 2022, 28,022,235 shares were available for future issuance pursuant to the 2021 Plan. 2021 Employee Stock Purchase Plan In June 2021, the Company adopted the 2021 Employee Stock Purchase Plan (“2021 ESPP”), which became effective immediately prior to the execution of the underwriting agreement related to the Company’s IPO with an initial reserve of 2,470,000 shares. The 2021 ESPP allows eligible employees to purchase shares of the Company’s common stock at a discount through payroll deductions of up to 15% of their earnings, subject to plan limitations. Unless otherwise determined by the Company’s board of directors, employees are able to purchase shares at 85% of the lower of the fair market value of the Company’s common stock on the first date of an offering or on the purchase date. The number of shares of the Company’s common stock reserved for issuance under the 2021 ESPP automatically increases on January 1 of each year for a period of ten years, beginning on January 1, 2022 and continuing through January 1, 2031, by the lesser of (1) 1% of the total number of shares of the Company’s common stock outstanding on December 31 of the immediately preceding year, and (2) 4,940,000 shares; provided, however, that the Company’s board of directors may act to provide a lesser increase in number of shares. On January 1, 2022, the Company reserved an additional 2,453,383 common shares for issuance under the 2021 ESPP representing 1% of the total common shares outstanding as of December 31, 2021. On March 29, 2022, the Company filed with the SEC a Form S-8 registering the additional shares. The Company may specify offerings with durations not more than 27 months and may specify shorter purchase periods within each offering. Under the 2021 ESPP, no shares and 283,574 shares were issued during the three and nine months ended September 30, 2022, respectively, and none for the three and nine months ended September 30, 2021. 2018 Equity Incentive Plan In 2018, the Company established the 2018 Plan that provided for the grant of incentive stock options, non-statutory stock options, RSAs, RSUs, stock appreciation rights and other stock-based awards. Terms of stock awards, including vesting requirements, were determined by the board of directors or by a committee authorized by the Company’s board of directors, subject to provisions of the 2018 Plan. The term of any stock option granted under the 2018 Plan cannot exceed ten years. Generally, awards granted by the Company vest over four years, but could have been granted with different vesting terms. Pursuant to the terms of the 2021 Plan, any shares subject to outstanding options originally granted under the 2018 Plan that terminate, expire or lapse for any reason without the delivery of shares to the holder thereof shall become available for issuance pursuant to awards granted under the 2021 Plan. While no shares are available for future issuance under the 2018 Plan, it continues to govern outstanding equity awards granted thereunder. Stock-based Compensation Expense Stock-based compensation expense by classification included within the condensed consolidated statements of operations and comprehensive loss was as follows (in thousands): Three Months Ended Nine Months Ended 2022 2021 2022 2021 Research and development $ 4,442 $ 2,673 $ 12,401 $ 12,615 General and administrative 14,681 10,369 51,160 28,408 Total stock-based compensation expense $ 19,123 $ 13,042 $ 63,561 $ 41,023 Stock-based compensation expense for the nine months ended September 30, 2021 includes the impact of an award accelerated in connection with the Company’s IPO resulting in stock-based compensation expense of $2.6 million. At September 30, 2022, total stock-based compensation cost related to unvested awards not yet recognized was $114.9 million, which is expected to be recognized over a remaining weighted-average period of 2.48 years. Restricted Stock Awards A summary of the Company’s RSA activity was as follows: Number of Shares Weighted-Average Unvested shares as of December 31, 2021 2,600,002 $ 0.0001 Vested (2,600,002) $ 0.0001 Unvested shares as of September 30, 2022 — $ — Restricted Stock Units A summary of the Company’s RSU activity was as follows: Restricted Stock Units Outstanding Weighted-Average Unvested RSUs as of December 31, 2021 — $ — RSUs granted 1,330,962 $ 5.98 RSUs vested (153,942) $ 5.98 RSUs forfeited or canceled (187,766) $ 5.98 Unvested RSUs as of September 30, 2022 989,254 $ 5.98 Stock Options A summary of the Company’s stock option activity was as follows: Number of Stock Options Weighted- Weighted- Aggregate Options outstanding as of December 31, 2021 41,775,179 $ 5.05 7.84 $ 142,076 Granted 9,931,442 $ 5.97 Exercised (3,512,765) $ 2.63 Canceled or forfeited (2,083,979) $ 6.07 Options outstanding as of September 30, 2022 46,109,877 $ 5.38 7.54 $ 120,296 Options exercisable as of September 30, 2022 26,446,733 $ 4.27 6.64 $ 94,486 The fair value of stock options granted to employees, directors and consultants was estimated on the date of grant using the Black-Scholes option pricing model using the following weighted-average assumptions: Nine Months Ended 2022 2021 Risk-free interest rate 2.32 % 0.79 % Expected volatility 85.6 % 78.7 % Expected term (in years) 5.98 6.10 Expected dividend yield 0 % 0 %

Net Loss Per Share

Net Loss Per Share	9 Months Ended
	Sep. 30, 2022
Earnings Per Share [Abstract]
Net Loss Per Share	Net Loss Per ShareBasic and diluted net loss per share is calculated by dividing net loss by the weighted-average number of common shares outstanding during the period, without consideration for common stock equivalents. The Company’s potentially dilutive shares, which include unvested RSAs, unvested RSUs and options to purchase common stock, are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive. Shares subject to options to purchase common stock, unvested RSAs and unvested RSUs were all excluded from consideration in the calculation of diluted net loss per share in all periods presented due to their anti-dilutive effects.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Collaboration and License Agreements The Company has entered into certain collaboration and license agreements, including those identified in Note 3, License, Collaboration and Success Payment Agreements above, with third parties that include the funding of certain development, manufacturing and commercialization efforts with the potential for future milestone and royalty payments upon the achievement of pre-established developmental, regulatory and/or commercial milestones. The Company’s obligation to fund these efforts is contingent upon continued involvement in the programs and/or the lack of any adverse events that could cause the discontinuance of the programs, including termination of such agreements. Due to the nature of these agreements, the future potential payments are inherently uncertain, and accordingly no amounts had been recorded for the potential future achievement of these targets as of September 30, 2022 and December 31, 2021.

Related-party Transactions

Related-party Transactions	9 Months Ended
	Sep. 30, 2022
Related Party Transactions [Abstract]
Related-party Transactions	Related-party Transactions In September 2021, the Company entered into a sublease with Sonoma, whereby the Company agreed to sublease approximately 18,000 square feet of space in South San Francisco, California currently leased by the Company. Dr. Klausner, the Chair of the Company’s board of directors, serves as a member of the board of directors of Sonoma, and he and certain holders of more than 5% of the Company’s outstanding common stock are also stockholders of Sonoma. As a part of the sublease, a $4.6 million tenant improvement contribution payment was made by Sonoma, which is recognized over the term of the sublease. As of September 30, 2022, there were accrued liabilities and other current liabilities of $0.5 million and other non-current liabilities of $3.6 million in connection with the sublease with Sonoma. Income of $0.7 million and $2.0 million, was recognized in other operating income, net for the three and nine months ended September 30, 2022, respectively, of which $0.5 million and $1.4 million was attributed to sublease income for the three and nine months ended September 30, 2022, respectively. See Note 7, Leases , for more detail on the Sonoma sublease. The Company is party to the GSK Agreement, who is a holder of more than 10% of the Company’s outstanding common stock. See Note 3, License, Collaboration and Success Payment Agreements . Deferred revenue of $11.2 million and $5.0 million as of September 30, 2022 and December 31, 2021, respectively, and deferred revenue, non-current of $37.2 million and $79.7 million as of September 30, 2022 and December 31, 2021, respectively, were in connection with the GSK Agreement. There was no revenue recognized in connection with the GSK agreement for the three months ended September 30, 2022. Revenue recognized in connection with the GSK agreement was $2.6 million for the three months ended September 30, 2021, and was $36.3 million and $7.7 million for the nine months ended September 30, 2022 and 2021, respectively. As discussed above, in October 2022, GSK provided notice to the Company of its decision to terminate the GSK Agreement, effective December 24, 2022. See Note 14, Subsequent Events , for additional details regarding termination of the GSK Agreement.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2022
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On October 1, 2022, the Company entered into a settlement agreement with PACT, pursuant to which the parties agreed to resolve their outstanding legal dispute. In connection with the settlement agreement, the parties also entered into a stock purchase agreement, pursuant to which PACT issued shares of PACT’s Series D convertible preferred stock to the Company in exchange for the Company’s tender of its PACT Series C-1 convertible preferred stock and resolution of the arbitration. The issuance of PACT’s Series D convertible preferred stock, which are non-voting, have limited conversion rights and carry no right to appoint directors, resulted in the Company’s ownership increasing to approximately 80% of PACT’s fully diluted shares outstanding. The settlement agreement also included the termination of the PACT Commitment Agreement to jointly develop a next generation anti-cancer T-cell therapy against solid tumors. The Company anticipates recording a legal settlement gain in the fourth quarter of 2022, subject to the valuation of the PACT Series D convertible preferred stock. On October 24, 2022, GSK provided notice to the Company of its decision to terminate the GSK Agreement, effective December 24, 2022. The IND application for LYL132 was cleared in January 2022, though no patients have been treated, and the IND for LYL331 has not yet been submitted to the U.S. Food and Drug Administration. Lyell has discontinued any further work on these programs. The Company anticipates recognizing the outstanding deferred revenue balance of $48.4 million as of September 30, 2022 in the fourth quarter of 2022.

Basis of Presentation and Sig_2

Basis of Presentation and Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Basis of Presentation	Basis of PresentationThe accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). The unaudited condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary.
Consolidations	All significant intercompany transactions and balances are eliminated in consolidation.
Reclassifications	Certain prior period amounts in the condensed consolidated financial statements and accompanying notes have been reclassified to conform to the current period’s presentation.
Use of Estimates	Use of Estimates The preparation of the Company’s condensed consolidated financial statements in conformity with GAAP requires management to make judgments, estimates and assumptions that affect reported amounts and related disclosures. Specific accounts that require management estimates include, but are not limited to, stock-based compensation, valuation of success payments, valuation of other investments, revenue recognition and accrued expenses. Management bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. Actual results could differ materially from those estimates. In June 2022, the Company recorded an adjustment to revenue related to a change in estimate in connection with the Collaboration and License Agreement, entered into in 2019 and amended in June 2020 and December 2021 (“GSK Agreement”) with GlaxoSmithKline Intellectual Property (No. 5) Limited and Glaxo Group Limited (together, “GSK”). The Company and GSK mutually agreed to conclude research activities on an undisclosed target for hematological cancers in June 2022. As a result, the Company decreased the related estimated project costs, which resulted in an increase in the measure of proportional cumulative performance. On October 24, 2022, GSK provided notice to the Company of its decision to terminate the GSK Agreement. The termination is effective on December 24, 2022. This adjustment increased revenue by $35.3 million, decreased net loss by $35.3 million and resulted in a $0.14 reduction in the Company’s basic and diluted net loss per common share for the nine months ended September 30, 2022.
Concentrations of Credit Risk	Concentrations of Credit Risk and Off-balance Sheet RiskThe Company maintains its cash, cash equivalents and restricted cash with high quality, accredited financial institutions. These amounts, at times, may exceed federally insured limits. The Company also makes short-term investments in money market funds, U.S. Treasury securities, U.S. government agency securities and corporate debt securities, which can be subject to certain credit risk. However, the Company mitigates the risks by investing in high-grade instruments, limiting exposure to any one issuer or type of investment and monitoring the ongoing creditworthiness of the financial institutions and issuers. The Company has not experienced any credit losses in such accounts and does not believe it is exposed to significant risk on these funds.
Off-balance Sheet Risk	The Company has no off-balance sheet concentrations of credit risk, such as foreign currency exchange contracts, option contracts or other hedging arrangements.
Significant Accounting Policies	Significant Accounting Policies There have been no material changes to the significant accounting policies from the Annual Report on Form 10-K for the year ended December 31, 2021.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements None.

License, Collaboration, and S_2

License, Collaboration, and Success Payment Agreements (Tables)	9 Months Ended
	Sep. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Aggregate Potential Success Payments	The following table summarizes the aggregate potential success payments, which are payable to Fred Hutch in cash or cash equivalents, or at the Company’s discretion, publicly-tradeable shares of the Company’s common stock: Multiple of initial equity value at issuance 10x 20x 30x 40x 50x Per share common stock price required for payment $ 18.29 $ 36.58 $ 54.86 $ 73.15 $ 91.44 Aggregate success payment(s) (in millions) $ 10 $ 40 $ 90 $ 140 $ 200 The following table summarizes the aggregate potential success payments, which are payable to Stanford in cash or cash equivalents or, at the Company’s discretion, publicly-tradeable shares of the Company’s common stock: Multiple of initial equity value at issuance 10x 20x 30x 40x 50x Per share common stock price required for payment $ 18.29 $ 36.58 $ 54.86 $ 73.15 $ 91.44 Aggregate success payment(s) (in millions) $ 10 $ 40 $ 90 $ 140 $ 200

Cash Equivalents and Marketab_2

Cash Equivalents and Marketable Securities (Tables)	9 Months Ended
	Sep. 30, 2022
Cash and Cash Equivalents [Abstract]
Schedule of Fair Value and Amortized Cost of Cash Equivalents	The fair value and amortized cost of cash equivalents and marketable securities by major security type are as follows (in thousands): September 30, 2022 Amortized Cost Gross Gross Unrealized Losses Fair Value Money market funds $ 42,608 $ — $ — $ 42,608 U.S. Treasury securities 313,281 — (6,972) 306,309 U.S. government agency securities 147,357 2 (1,716) 145,643 Corporate debt securities 235,749 1 (1,311) 234,439 Total cash equivalents and marketable securities $ 738,995 $ 3 $ (9,999) $ 728,999 Classified as: Fair Value Cash equivalents $ 94,659 Marketable securities 531,821 Marketable securities, non-current 102,519 Total cash equivalents and marketable securities $ 728,999 December 31, 2021 Amortized Cost Gross Gross Unrealized Losses Fair Value Money market funds $ 206,245 $ — $ — $ 206,245 U.S. Treasury securities 290,909 2 (1,205) 289,706 U.S. government agency securities 93,864 2 (240) 93,626 Corporate debt securities 285,338 — (182) 285,156 Total cash equivalents and marketable securities $ 876,356 $ 4 $ (1,627) $ 874,733 Classified as: Fair Value Cash equivalents $ 270,236 Marketable securities 320,966 Marketable securities, non-current 283,531 Total cash equivalents and marketable securities $ 874,733
Schedule of Fair Value and Amortized Cost of Marketable Securities	The fair value and amortized cost of cash equivalents and marketable securities by major security type are as follows (in thousands): September 30, 2022 Amortized Cost Gross Gross Unrealized Losses Fair Value Money market funds $ 42,608 $ — $ — $ 42,608 U.S. Treasury securities 313,281 — (6,972) 306,309 U.S. government agency securities 147,357 2 (1,716) 145,643 Corporate debt securities 235,749 1 (1,311) 234,439 Total cash equivalents and marketable securities $ 738,995 $ 3 $ (9,999) $ 728,999 Classified as: Fair Value Cash equivalents $ 94,659 Marketable securities 531,821 Marketable securities, non-current 102,519 Total cash equivalents and marketable securities $ 728,999 December 31, 2021 Amortized Cost Gross Gross Unrealized Losses Fair Value Money market funds $ 206,245 $ — $ — $ 206,245 U.S. Treasury securities 290,909 2 (1,205) 289,706 U.S. government agency securities 93,864 2 (240) 93,626 Corporate debt securities 285,338 — (182) 285,156 Total cash equivalents and marketable securities $ 876,356 $ 4 $ (1,627) $ 874,733 Classified as: Fair Value Cash equivalents $ 270,236 Marketable securities 320,966 Marketable securities, non-current 283,531 Total cash equivalents and marketable securities $ 874,733

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2022
Fair Value Disclosures [Abstract]
Financial Assets and Liabilities Measured at Fair Value on Recurring Basis	The following table sets forth the fair value of the Company’s financial assets and liabilities measured at fair value on a recurring basis based on the three-tier fair value hierarchy (in thousands): September 30, 2022 Level 1 Level 2 Level 3 Total Financial assets: Money market funds $ 42,608 $ — $ — $ 42,608 U.S. Treasury securities — 306,309 — 306,309 U.S. government agency securities — 145,643 — 145,643 Corporate debt securities — 234,439 — 234,439 Total financial assets $ 42,608 $ 686,391 $ — $ 728,999 Financial liabilities: Success payment liabilities $ — $ — $ 11,663 $ 11,663 Total financial liabilities $ — $ — $ 11,663 $ 11,663 December 31, 2021 Level 1 Level 2 Level 3 Total Financial assets: Money market funds $ 206,245 $ — $ — $ 206,245 U.S. Treasury securities — 289,706 — 289,706 U.S. government agency securities — 93,626 — 93,626 Corporate debt securities — 285,156 — 285,156 Equity warrant investment — — 1,067 1,067 Total financial assets $ 206,245 $ 668,488 $ 1,067 $ 875,800 Financial liabilities: Success payment liabilities $ — $ — $ 9,486 $ 9,486 Total financial liabilities $ — $ — $ 9,486 $ 9,486
Summary of Estimated Fair Value of Success Payment Liability Assumptions	The following assumptions were incorporated into the calculation of the estimated fair value of the Fred Hutch success payment liability: September 30, December 31, Fair value of common stock $ 7.33 $ 7.74 Risk-free interest rate 3.66% - 4.26% 0.19% - 1.88% Expected volatility 80.0 % 75.0 % Expected term (in years) 0.71 - 5.22 0.46 - 5.97 The following assumptions were incorporated into the calculation of the estimated fair value of the Stanford success payment liability: September 30, December 31, Fair value of common stock $ 7.33 $ 7.74 Risk-free interest rate 3.66% - 4.26% 0.19% - 1.88% Expected volatility 80.0 % 75.0 % Expected term (in years) 0.71 - 7.00 0.46 - 7.75
Changes in the Estimated Fair Value of Level 3 Financial Assets	The following table sets forth a summary of the changes in the fair value of the Company’s Level 3 financial assets and liabilities (in thousands): Equity Warrant Success Payment Balance at December 31, 2021 $ 1,067 $ 9,486 Change in fair value (1) (1,067) 2,177 Balance at September 30, 2022 $ — $ 11,663 (1) The change in fair value associated with the equity warrant investment held is recorded in other (expense) income, net and the change in fair value associated with success payment liabilities is recorded in research and development expense.
Changes in the Estimated Fair Value of Level 3 Financial Liabilities	The following table sets forth a summary of the changes in the fair value of the Company’s Level 3 financial assets and liabilities (in thousands): Equity Warrant Success Payment Balance at December 31, 2021 $ 1,067 $ 9,486 Change in fair value (1) (1,067) 2,177 Balance at September 30, 2022 $ — $ 11,663 (1) The change in fair value associated with the equity warrant investment held is recorded in other (expense) income, net and the change in fair value associated with success payment liabilities is recorded in research and development expense.

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2022
Leases [Abstract]
Schedule of Future Minimum Operating Lease Commitments, Including Expected Lease Incentives to be Received	The following table summarizes the Company’s future minimum operating lease commitments, including expected lease incentives to be received, as of September 30, 2022 (in thousands): Year Ending December 31: 2022 (remaining three months) $ 1,822 2023 11,018 2024 11,347 2025 11,859 2026 12,209 Thereafter 48,094 Total undiscounted lease payments 96,349 Less: imputed interest (27,351) Less: tenant improvement allowances (1,523) Total operating lease liabilities $ 67,475 Reported as of September 30, 2022: Short-term portion of lease liabilities (included in accrued liabilities and other current liabilities) $ 2,839 Operating lease liabilities, non-current 64,636 Total $ 67,475
Schedule of Lease Assets and Liabilities	The following table summarizes the Company’s future minimum operating lease commitments, including expected lease incentives to be received, as of September 30, 2022 (in thousands): Year Ending December 31: 2022 (remaining three months) $ 1,822 2023 11,018 2024 11,347 2025 11,859 2026 12,209 Thereafter 48,094 Total undiscounted lease payments 96,349 Less: imputed interest (27,351) Less: tenant improvement allowances (1,523) Total operating lease liabilities $ 67,475 Reported as of September 30, 2022: Short-term portion of lease liabilities (included in accrued liabilities and other current liabilities) $ 2,839 Operating lease liabilities, non-current 64,636 Total $ 67,475

Stock-based Compensation (Table

Stock-based Compensation (Tables)	9 Months Ended
	Sep. 30, 2022
Share-based Payment Arrangement [Abstract]
Schedule of Stock-based Compensation Expense by Classification	Stock-based compensation expense by classification included within the condensed consolidated statements of operations and comprehensive loss was as follows (in thousands): Three Months Ended Nine Months Ended 2022 2021 2022 2021 Research and development $ 4,442 $ 2,673 $ 12,401 $ 12,615 General and administrative 14,681 10,369 51,160 28,408 Total stock-based compensation expense $ 19,123 $ 13,042 $ 63,561 $ 41,023
Summary of RSA Activity	A summary of the Company’s RSA activity was as follows: Number of Shares Weighted-Average Unvested shares as of December 31, 2021 2,600,002 $ 0.0001 Vested (2,600,002) $ 0.0001 Unvested shares as of September 30, 2022 — $ —
Summary of RSU Activity	A summary of the Company’s RSU activity was as follows: Restricted Stock Units Outstanding Weighted-Average Unvested RSUs as of December 31, 2021 — $ — RSUs granted 1,330,962 $ 5.98 RSUs vested (153,942) $ 5.98 RSUs forfeited or canceled (187,766) $ 5.98 Unvested RSUs as of September 30, 2022 989,254 $ 5.98
Summary of Stock Option Activity	A summary of the Company’s stock option activity was as follows: Number of Stock Options Weighted- Weighted- Aggregate Options outstanding as of December 31, 2021 41,775,179 $ 5.05 7.84 $ 142,076 Granted 9,931,442 $ 5.97 Exercised (3,512,765) $ 2.63 Canceled or forfeited (2,083,979) $ 6.07 Options outstanding as of September 30, 2022 46,109,877 $ 5.38 7.54 $ 120,296 Options exercisable as of September 30, 2022 26,446,733 $ 4.27 6.64 $ 94,486
Schedule of Assumptions Used in Black-Scholes Option-Pricing Model for Estimating Fair Value of Stock Options Granted	The fair value of stock options granted to employees, directors and consultants was estimated on the date of grant using the Black-Scholes option pricing model using the following weighted-average assumptions: Nine Months Ended 2022 2021 Risk-free interest rate 2.32 % 0.79 % Expected volatility 85.6 % 78.7 % Expected term (in years) 5.98 6.10 Expected dividend yield 0 % 0 %

Organization (Details)

Organization (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	9 Months Ended
	Jun. 30, 2021	Sep. 30, 2021
Description of Organization [Line Items]
Offering expenses		$ 33,198
Common Stock
Description of Organization [Line Items]
Issuance of common stock (in shares)		25,000,000
Conversion of preferred stock into common stock (in shares)		194,474,000
IPO | Convertible Preferred Stock
Description of Organization [Line Items]
Conversion of preferred stock into common stock (in shares)	194,474,431
IPO | Common Stock
Description of Organization [Line Items]
Issuance of common stock (in shares)	25,000,000
Common stock, par value (in dollars per share)	$ 17
Net proceeds from sale of stock, after underwriting discounts and commissions	$ 391,800
Payments of underwriting discounts and commissions	29,800
Offering expenses	3,400
IPO | Common Stock Including Additional Paid in Capital
Description of Organization [Line Items]
Converted preferred stock	$ 1,000,000

Basis of Presentation and Sig_3

Basis of Presentation and Significant Accounting Policies (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue	[1]	$ 3	$ 2,755	$ 36,297	$ 7,828
Net loss		$ (70,254)	$ (48,875)	$ (174,721)	$ (166,513)
Net loss per common share, basic (in dollars per share)		$ (0.28)	$ (0.20)	$ (0.71)	$ (1.66)
Net loss per common share, diluted (in dollars per share)		$ (0.28)	$ (0.20)	$ (0.71)	$ (1.66)
GSK | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Adjustment To Revenue Related To Change In Estimate
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue				$ 35,300
Net loss				$ 35,300
Net loss per common share, basic (in dollars per share)				$ 0.14
Net loss per common share, diluted (in dollars per share)				$ 0.14
[1]Including related-party revenue of zero and $2,640 for the three months ended September 30, 2022 and 2021, respectively, and $36,299 and $7,697 for the nine months ended September 30, 2022 and 2021, respectively.

License, Collaboration, and S_3

License, Collaboration, and Success Payment Agreements - Narrative (Details)		1 Months Ended		3 Months Ended			9 Months Ended
		Jun. 30, 2020 USD ($) $ / shares shares	May 31, 2019 $ / shares shares	Sep. 30, 2022 USD ($) performance_obligation $ / shares	Dec. 31, 2021 USD ($)	Sep. 30, 2021 USD ($) $ / shares	Sep. 30, 2022 USD ($) performance_obligation $ / shares	Sep. 30, 2021 USD ($) $ / shares	Oct. 01, 2022	Apr. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)	Oct. 31, 2020 USD ($) $ / shares	Sep. 30, 2020 USD ($)	Dec. 31, 2019 USD ($) collaboration_target representative payment	Dec. 31, 2018 USD ($) $ / shares
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development expense				$ 41,607,000		$ 31,433,000	$ 121,156,000	$ 119,408,000
Revenue	[1]			3,000		2,755,000	36,297,000	7,828,000
Net loss				$ (70,254,000)		$ (48,875,000)	$ (174,721,000)	$ (166,513,000)
Net loss per common share, basic (in dollars per share) | $ / shares				$ (0.28)		$ (0.20)	$ (0.71)	$ (1.66)
Net loss per common share, diluted (in dollars per share) | $ / shares				$ (0.28)		$ (0.20)	$ (0.71)	$ (1.66)
Impairment of other investments				$ 5,000,000		$ 0	$ 5,000,000	$ 0
Settled Litigation | Subsequent Event
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Ownership of fully diluted shares (as a percent)									80%
PACT
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Impairment of other investments					$ 36,400,000
Series A Convertible Preferred Stock
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Convertible preferred stock, par value (in dollars per share) | $ / shares												$ 1.83			$ 1.83
Fred Hutch | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Annual license maintenance payments															$ 50,000
Aggregate research payments due															$ 12,000,000
Term of collaborative arrangement for research															6 years
Research and development expense				400,000		1,100,000	1,400,000	3,100,000
Aggregate success payment(s) (in millions)				0			0
Term of success payment agreement															9 years
Trigger period from IPO date															1 year
Trigger period thereafter															2 years
Fair value of potential success payments due				7,700,000	8,500,000		7,700,000
Success payment liability				7,200,000	6,400,000		7,200,000
Success payment expenses				1,400,000		(800,000)	800,000	14,100,000
Fred Hutch | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Minimum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Multiple of initial equity value at issuance															10
Aggregate success payment(s) (in millions)															$ 10,000,000
Per share common stock price required for payment (in dollars per share) | $ / shares															$ 18.29
Fred Hutch | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Multiple of initial equity value at issuance															50
Aggregate success payment(s) (in millions)															$ 200,000,000
Per share common stock price required for payment (in dollars per share) | $ / shares															$ 91.44
Stanford | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Annual license maintenance payments														$ 50,000
Aggregate research payments due												$ 12,000,000
Term of collaborative arrangement for research												4 years
Research and development expense				800,000		800,000	2,300,000	2,300,000
Aggregate success payment(s) (in millions)				0			0
Term of success payment agreement												9 years
Trigger period from IPO date												1 year
Trigger period thereafter												2 years
Fair value of potential success payments due				8,900,000	9,900,000		8,900,000
Success payment liability				4,500,000	3,100,000		4,500,000
Success payment expenses				1,000,000		1,000,000	1,400,000	5,200,000
Stanford | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | License
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential milestone payments due														2,500,000
Stanford | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Minimum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Multiple of initial equity value at issuance												10
Aggregate success payment(s) (in millions)												$ 10,000,000
Per share common stock price required for payment (in dollars per share) | $ / shares												$ 18.29
Stanford | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Multiple of initial equity value at issuance												50
Aggregate success payment(s) (in millions)												$ 200,000,000
Per share common stock price required for payment (in dollars per share) | $ / shares												$ 91.44
Stanford | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Maximum | License
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential milestone payments due														$ 3,700,000
GSK | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contract liabilities				48,400,000	$ 84,700,000		48,400,000
Revenue recognized				0		2,600,000	36,300,000	7,700,000
GSK | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | License
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of initial collaboration targets | collaboration_target														2
Number of additional collaboration targets | collaboration_target														7
Number of representatives of JSC appointed by company | representative														3
Contract liabilities				$ 0			$ 0				$ 45,000,000			$ 45,000,000
Revenue, remaining performance obligation, variable consideration amount, number of one-time payments | payment														2
Stock Purchase Agreement portion of transaction price											58,600,000
Transaction price											$ 103,600,000
Number of performance obligations | performance_obligation				2			2
Revenue recognized				$ 0		$ 0	$ 0	$ 0
Contract assets				0			0
Capitalized contract costs				$ 0			0
GSK | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | License | Series AA Convertible Preferred Stock
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Stock sold under Stock Purchase Program (in shares) | shares			30,253,189
Price per share of stock sold under Stock Purchase Program (in dollars per share) | $ / shares			$ 6.78
Fair value per share of stock sold under Stock Purchase Program (in dollars per share) | $ / shares			$ 4.84
GSK | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Maximum | License
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential milestone payments, technology validation														$ 200,000,000
Potential milestone payments, within pipeline														400,000,000
Potential milestone payments, not within pipeline														$ 900,000,000
Variable consideration amount										$ 400,000,000
GSK | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Adjustment To Revenue Related To Change In Estimate
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue							35,300,000
Net loss							$ 35,300,000
Net loss per common share, basic (in dollars per share) | $ / shares							$ 0.14
Net loss per common share, diluted (in dollars per share) | $ / shares							$ 0.14
PACT | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payment		$ 50,000,000
Stock purchase agreement, stock purchased (in shares) | shares		17,806,901
Stock purchase agreement, purchase price per share (in dollars per share) | $ / shares		$ 2.81
Stock purchase agreement, fair value per share (in dollars per share) | $ / shares		$ 2.05
Additional purchase price consideration													$ 13,600,000
Total upfront payment paid													63,600,000
PACT | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Other Investment
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Strategic equity investment													$ 36,400,000
[1]Including related-party revenue of zero and $2,640 for the three months ended September 30, 2022 and 2021, respectively, and $36,299 and $7,697 for the nine months ended September 30, 2022 and 2021, respectively.

License, Collaboration, and S_4

License, Collaboration, and Success Payment Agreements - Schedule of Aggregate Potential Success Payments (Details) - Collaborative Arrangement, Transaction with Party to Collaborative Arrangement	Sep. 30, 2022 USD ($)	Oct. 31, 2020 USD ($) $ / shares	Dec. 31, 2018 USD ($) $ / shares
Fred Hutch
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Aggregate success payment(s) (in millions)	$ 0
Stanford
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Aggregate success payment(s) (in millions)	$ 0
Ten Times | Fred Hutch
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Multiple of initial equity value at issuance			10
Per share common stock price required for payment (in dollars per share) | $ / shares			$ 18.29
Aggregate success payment(s) (in millions)			$ 10,000,000
Ten Times | Stanford
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Multiple of initial equity value at issuance		10
Per share common stock price required for payment (in dollars per share) | $ / shares		$ 18.29
Aggregate success payment(s) (in millions)		$ 10,000,000
Twenty Times | Fred Hutch
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Multiple of initial equity value at issuance			20
Per share common stock price required for payment (in dollars per share) | $ / shares			$ 36.58
Aggregate success payment(s) (in millions)			$ 40,000,000
Twenty Times | Stanford
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Multiple of initial equity value at issuance		20
Per share common stock price required for payment (in dollars per share) | $ / shares		$ 36.58
Aggregate success payment(s) (in millions)		$ 40,000,000
Thirty Times | Fred Hutch
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Multiple of initial equity value at issuance			30
Per share common stock price required for payment (in dollars per share) | $ / shares			$ 54.86
Aggregate success payment(s) (in millions)			$ 90,000,000
Thirty Times | Stanford
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Multiple of initial equity value at issuance		30
Per share common stock price required for payment (in dollars per share) | $ / shares		$ 54.86
Aggregate success payment(s) (in millions)		$ 90,000,000
Forty Times | Fred Hutch
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Multiple of initial equity value at issuance			40
Per share common stock price required for payment (in dollars per share) | $ / shares			$ 73.15
Aggregate success payment(s) (in millions)			$ 140,000,000
Forty Times | Stanford
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Multiple of initial equity value at issuance		40
Per share common stock price required for payment (in dollars per share) | $ / shares		$ 73.15
Aggregate success payment(s) (in millions)		$ 140,000,000
Fifty Times | Fred Hutch
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Multiple of initial equity value at issuance			50
Per share common stock price required for payment (in dollars per share) | $ / shares			$ 91.44
Aggregate success payment(s) (in millions)			$ 200,000,000
Fifty Times | Stanford
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Multiple of initial equity value at issuance		50
Per share common stock price required for payment (in dollars per share) | $ / shares		$ 91.44
Aggregate success payment(s) (in millions)		$ 200,000,000

Cash Equivalents and Marketab_3

Cash Equivalents and Marketable Securities - Schedule of Fair Value and Amortized Cost of Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021
Marketable Securities [Line Items]
Amortized Cost	$ 116,311	$ 293,828	$ 393,504
Amortized Cost	738,995	876,356
Gross Unrealized Gains	3	4
Gross Unrealized Losses	(9,999)	(1,627)
Fair Value	728,999	874,733
Classified as:
Cash equivalents	94,659	270,236
Marketable securities	531,821	320,966
Marketable securities, non-current	102,519	283,531
Total cash equivalents and marketable securities	728,999	874,733
U.S. Treasury securities
Marketable Securities [Line Items]
Amortized Cost	313,281	290,909
Gross Unrealized Gains	0	2
Gross Unrealized Losses	(6,972)	(1,205)
Fair Value	306,309	289,706
U.S. government agency securities
Marketable Securities [Line Items]
Amortized Cost	147,357	93,864
Gross Unrealized Gains	2	2
Gross Unrealized Losses	(1,716)	(240)
Fair Value	145,643	93,626
Corporate debt securities
Marketable Securities [Line Items]
Amortized Cost	235,749	285,338
Gross Unrealized Gains	1	0
Gross Unrealized Losses	(1,311)	(182)
Fair Value	234,439	285,156
Money market funds
Marketable Securities [Line Items]
Amortized Cost	42,608	206,245
Fair Value	$ 42,608	$ 206,245

Cash Equivalents and Marketab_4

Cash Equivalents and Marketable Securities - Narrative (Details) - USD ($)	Sep. 30, 2022	Dec. 31, 2021
Marketable Securities [Line Items]
Fair value of securities held in a continuous unrealized loss position for less than twelve months	$ 507,300,000	$ 602,900,000
Fair value of securities held in a continuous unrealized loss position for greater than twelve months	$ 126,500,000	$ 0
Maximum
Marketable Securities [Line Items]
Maturity of marketable securities	2 years	2 years

Other Investments (Details)

Other Investments (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Nov. 30, 2020
Schedule of Investments [Line Items]
Other investments	$ 42,001	$ 47,001		$ 42,001
Impairment of other investments	5,000		$ 0	5,000	$ 0
Variable Interest Entity, Not Primary Beneficiary | Outpace Bio Inc
Schedule of Investments [Line Items]
Other investments	13,000	13,000		13,000		$ 13,000
Other Investment
Schedule of Investments [Line Items]
Other investments	5,000			$ 5,000
Impairment of other investments	$ 5,000
PACT
Schedule of Investments [Line Items]
Other investments		36,400
Impairment of other investments		$ 36,400

Fair Value Measurements - Finan

Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Financial assets:
Equity warrant investment		$ 1,067
Total financial assets	$ 728,999	875,800
Financial liabilities:
Success payment liabilities	11,663	9,486
Total financial liabilities	11,663	9,486
U.S. Treasury securities
Financial assets:
Marketable securities	306,309	289,706
U.S. government agency securities
Financial assets:
Marketable securities	145,643	93,626
Corporate debt securities
Financial assets:
Marketable securities	234,439	285,156
Money market funds
Financial assets:
Money market funds	42,608	206,245
Level 1
Financial assets:
Equity warrant investment		0
Total financial assets	42,608	206,245
Financial liabilities:
Success payment liabilities	0	0
Total financial liabilities	0	0
Level 1 | U.S. Treasury securities
Financial assets:
Marketable securities	0	0
Level 1 | U.S. government agency securities
Financial assets:
Marketable securities	0	0
Level 1 | Corporate debt securities
Financial assets:
Marketable securities	0	0
Level 1 | Money market funds
Financial assets:
Money market funds	42,608	206,245
Level 2
Financial assets:
Equity warrant investment		0
Total financial assets	686,391	668,488
Financial liabilities:
Success payment liabilities	0	0
Total financial liabilities	0	0
Level 2 | U.S. Treasury securities
Financial assets:
Marketable securities	306,309	289,706
Level 2 | U.S. government agency securities
Financial assets:
Marketable securities	145,643	93,626
Level 2 | Corporate debt securities
Financial assets:
Marketable securities	234,439	285,156
Level 2 | Money market funds
Financial assets:
Money market funds	0	0
Level 3
Financial assets:
Equity warrant investment		1,067
Total financial assets	0	1,067
Financial liabilities:
Success payment liabilities	11,663	9,486
Total financial liabilities	11,663	9,486
Level 3 | U.S. Treasury securities
Financial assets:
Marketable securities	0	0
Level 3 | U.S. government agency securities
Financial assets:
Marketable securities	0	0
Level 3 | Corporate debt securities
Financial assets:
Marketable securities	0	0
Level 3 | Money market funds
Financial assets:
Money market funds	$ 0	$ 0

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) $ in Thousands	Dec. 31, 2021 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity warrant investment	$ 1,067
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity warrant investment	$ 1,067

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Estimated Fair Value of Success Payment Liability Assumptions (Details)	Sep. 30, 2022 $ / shares	Dec. 31, 2021 $ / shares
Fred Hutch
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of common stock Series A convertible preferred stock	$ 7.33	$ 7.74
Fred Hutch | Risk-free interest rate | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Success payment liability, measurement input (as a percent)	3.66	0.19
Fred Hutch | Risk-free interest rate | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Success payment liability, measurement input (as a percent)	4.26	1.88
Fred Hutch | Expected volatility
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Success payment liability, measurement input (as a percent)	0.800	0.750
Fred Hutch | Expected term (in years) | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Success payment liability, measurement input (as a percent)	0.71	0.46
Fred Hutch | Expected term (in years) | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Success payment liability, measurement input (as a percent)	5.22	5.97
Stanford
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of common stock Series A convertible preferred stock	$ 7.33	$ 7.74
Stanford | Risk-free interest rate | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Success payment liability, measurement input (as a percent)	3.66	0.19
Stanford | Risk-free interest rate | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Success payment liability, measurement input (as a percent)	4.26	1.88
Stanford | Expected volatility
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Success payment liability, measurement input (as a percent)	0.800	0.750
Stanford | Expected term (in years) | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Success payment liability, measurement input (as a percent)	0.71	0.46
Stanford | Expected term (in years) | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Success payment liability, measurement input (as a percent)	7	7.75

Fair Value Measurements - Sum_2

Fair Value Measurements - Summary of Changes in Estimated Fair Value of Financial Liabilities (Details) - Level 3	9 Months Ended
	Sep. 30, 2022 USD ($)
Equity Warrant Investment
Equity Warrant Investment
Balance at December 31, 2021	$ 1,067,000
Changes in fair value	(1,067,000)
Balance at September 30, 2022	0
Success Payment Liabilities
Success Payment Liabilities
Balance at December 31, 2021	9,486,000
Change in fair value	2,177,000
Balance at September 30, 2022	$ 11,663,000

Leases - Summary of Operating L

Leases - Summary of Operating Lease Commitments Including Expected Lease Incentives to be Received (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Leases [Abstract]
2022 (remaining three months)	$ 1,822
2023	11,018
2024	11,347
2025	11,859
2026	12,209
Thereafter	48,094
Total undiscounted lease payments	96,349
Less: imputed interest	(27,351)
Less: tenant improvement allowances	(1,523)
Total operating lease liabilities	67,475
Operating Lease Liability
Short-term portion of lease liabilities (included in accrued liabilities and other current liabilities)	2,839
Operating lease liabilities, non-current	64,636	$ 66,650
Total	$ 67,475

Leases - Narrative (Details)

Leases - Narrative (Details) ft² in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($) ft²	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($) ft²	Dec. 31, 2021	May 31, 2021 ft²
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 2.3	$ 2.4	$ 7	$ 7.1
Variable lease cost	$ 1.3	1.4	$ 3.8	3.7
Weighted average remaining lease term of operating leases	8 years		8 years		8 years 9 months 18 days
Operating lease, weighted average discount rate (as a percent)	8.50%		8.50%		8.40%
South San Francisco, California
Lessee, Lease, Description [Line Items]
Rentable area | ft²						11
Sublease income	$ 0.2	$ 0.1	$ 0.6	$ 0.1
Affiliated Entity | Sublease with Sonoma
Lessee, Lease, Description [Line Items]
Rentable area | ft²		18		18
Sublease income	$ 0.5	$ 0.2	$ 1.4	$ 0.2
Tenant improvements		$ 4.6		$ 4.6

Convertible Preferred Stock (De

Convertible Preferred Stock (Details) - shares	Sep. 30, 2022	Dec. 31, 2021	Jun. 30, 2021
Equity [Abstract]
Outstanding shares of convertible preferred stock converted into shares of common stock (in shares)			194,474,431
Convertible preferred stock outstanding (in shares)	0	0

Stockholders' Equity (Details)

Stockholders' Equity (Details) - USD ($)	Aug. 04, 2022	Sep. 30, 2022	Dec. 31, 2021
Class of Stock [Line Items]
Preferred stock authorized (in shares)		10,000,000	10,000,000
Preferred stock, par value (in dollars per share)		$ 0.0001	$ 0.0001
Preferred stock outstanding (in shares)		0	0
Common stock authorized (in shares)		500,000,000	500,000,000
Common stock, par value (in dollars per share)		$ 0.0001	$ 0.0001
Common stock outstanding (in shares)		249,239,833	242,738,350
Goldman Sachs and BofA | At The Market Offering | Equity Distribution Agreement
Class of Stock [Line Items]
Aggregate offering amount	$ 200,000,000
Percentage of commission from each sale of shares	3%
RSAs
Class of Stock [Line Items]
Awards outstanding (in shares)		0	2,600,002

Stock-based Compensation - Narr

Stock-based Compensation - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		9 Months Ended		12 Months Ended
	Jan. 01, 2022	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2018	Jun. 30, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense		$ 19,123	$ 13,042	$ 63,561	$ 41,023
Total stock-based compensation cost related to unvested awards not yet recognized		$ 114,900		$ 114,900
Expected weighted-average period compensation cost to be recognized				2 years 5 months 23 days
Weighted average grant date fair value (in dollars per share)				$ 4.33	$ 6.55
IPO
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense					$ 2,600
2021 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common shares reserved for future issuance (in shares)							26,662,087
Award expiration period				10 years
Proportion of stock outstanding (as a percent)				5%
Number of additional shares authorized for issuance (in shares)	12,266,917
Increase in proportion of common shares reserved for future issuance (as a percent)	5%
Vesting period				4 years
Future issuance of common shares (in shares)		28,022,235		28,022,235
2021 Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award expiration period				10 years
2021 ESPP
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common shares reserved for future issuance (in shares)							2,470,000
Award expiration period				10 years
Proportion of stock outstanding (as a percent)				1%
Number of additional shares authorized for issuance (in shares)	2,453,383
Increase in proportion of common shares reserved for future issuance (as a percent)	1%
Purchase of common stock at discount (as a percent)		15%		15%
Employee purchase of shares, proportion of fair value (as a percent)				85%
Maximum number of shares to be purchased under ESPP (in shares)				4,940,000
Maximum offering period				27 months
Stock-based compensation (in shares)		0	0	283,574	0
2018 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award expiration period						10 years
Vesting period						4 years
Future issuance of common shares (in shares)		0		0

Stock-based Compensation - Sche

Stock-based Compensation - Schedule of Stock-Based Compensation Expense by Classification (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 19,123	$ 13,042	$ 63,561	$ 41,023
Research and development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	4,442	2,673	12,401	12,615
General and administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 14,681	$ 10,369	$ 51,160	$ 28,408

Stock-based Compensation - Summ

Stock-based Compensation - Summary of RSA Activity (Details) - RSAs	9 Months Ended
	Sep. 30, 2022 $ / shares shares
Number of Shares
Balance at beginning of period (in shares) | shares	2,600,002
Vested (in shares) | shares	(2,600,002)
Balance at end of period (in shares) | shares	0
Weighted-Average Value at Grant Date Per Share
Balance at beginning of period (in dollars per share) | $ / shares	$ 0.0001
Vested (in dollars per share) | $ / shares	0.0001
Balance at end of period (in dollars per share) | $ / shares	$ 0

Stock-based Compensation - Rest

Stock-based Compensation - Restricted Stock Units (Details) - RSUs	9 Months Ended
	Sep. 30, 2022 $ / shares shares
Number of Shares
Balance at beginning of period (in shares) | shares	0
Granted (in shares) | shares	1,330,962
Vested (in shares) | shares	(153,942)
Forfeited or canceled (in shares) | shares	(187,766)
Balance at end of period (in shares) | shares	989,254
Weighted-Average Value at Grant Date Per Share
Balance at beginning of period (in dollars per share) | $ / shares	$ 0
Granted (in dollars per share) | $ / shares	5.98
Vested (in dollars per share) | $ / shares	5.98
Forfeited or canceled (in dollars per share) | $ / shares	5.98
Balance at end of period (in dollars per share) | $ / shares	$ 5.98

Stock-based Compensation - Su_2

Stock-based Compensation - Summary of Stock Option Activity (Details) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2022 USD ($) $ / shares shares	Dec. 31, 2021 USD ($) $ / shares shares
Number of Stock Options
Beginning balance (in shares) | shares	41,775,179
Granted (in shares) | shares	9,931,442
Exercised (in shares) | shares	(3,512,765)
Canceled or forfeited (in shares) | shares	(2,083,979)
Ending balance (in shares) | shares	46,109,877	41,775,179
Exercisable (in shares) | shares	26,446,733
Weighted- Average Exercise Price Per Share
Beginning balance (in dollars per share) | $ / shares	$ 5.05
Granted (in dollars per share) | $ / shares	5.97
Exercised (in dollars per share) | $ / shares	2.63
Cancelled or forfeited (in dollars per share) | $ / shares	6.07
Ending balance (in dollars per share) | $ / shares	5.38	$ 5.05
Exercisable (in dollars per share) | $ / shares	$ 4.27
Weighted- Average Remaining Contractual Life (in years)
Options Outstanding	7 years 6 months 14 days	7 years 10 months 2 days
Options Exercisable	6 years 7 months 20 days
Aggregate Intrinsic Value (in thousands)
Options Outstanding | $	$ 120,296	$ 142,076
Options Exercisable | $	$ 94,486

Stock-based Compensation - Sc_2

Stock-based Compensation - Schedule of Assumptions Used in Black-Scholes Option-Pricing Model for Estimating Fair Value of Stock Options Granted (Details)	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
Risk-free interest rate (as a percent)	2.32%	0.79%
Expected volatility (as a percent)	85.60%	78.70%
Expected term (in years)	5 years 11 months 23 days	6 years 1 month 6 days
Expected dividend yield (as a percent)	0%	0%

Related-party Transactions (Det

Related-party Transactions (Details) ft² in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($) ft²	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($) ft²	Dec. 31, 2021 USD ($)
Related Party Transaction [Line Items]
Due to related parties, current	$ 11,191,000		$ 11,191,000		$ 4,988,000
Due to related parties, noncurrent	37,163,000		37,163,000		79,665,000
Related-Party revenue	0	$ 2,640,000	36,299,000	$ 7,697,000
Affiliated Entity | Sublease with Sonoma
Related Party Transaction [Line Items]
Rentable area | ft²		18		18
Tenant improvements		$ 4,600,000		$ 4,600,000
Due to related parties, current	500,000		500,000
Due to related parties, noncurrent	3,600,000		3,600,000
Related-Party revenue	700,000		2,000,000
Sublease income	$ 500,000	200,000	$ 1,400,000	200,000
Affiliated Entity | Sublease with Sonoma | Minimum | Lyell Immunopharma
Related Party Transaction [Line Items]
Ownership interest (as a percent)	5%		5%
Investor | GSK Agreement
Related Party Transaction [Line Items]
Due to related parties, current	$ 11,200,000		$ 11,200,000		5,000,000
Due to related parties, noncurrent	37,200,000		37,200,000		$ 79,700,000
Related-Party revenue	$ 0	$ 2,600,000	$ 36,300,000	$ 7,700,000
Investor | GSK Agreement | Minimum | Lyell Immunopharma | GSK
Related Party Transaction [Line Items]
Ownership interest (as a percent)	10%		10%

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2022	Oct. 01, 2022
Forecast
Subsequent Event [Line Items]
Estimated outstanding deferred revenue	$ 48.4
Settled Litigation | Subsequent Event
Subsequent Event [Line Items]
Ownership of fully diluted shares (as a percent)		80%