Arcus Biosciences (RCUS) 10-Q6 Nov 242024 Q3 Quarterly reportFinancial data

Company Profile

Cover

Cover - shares	9 Months Ended
Cover - shares	Sep. 30, 2024	Oct. 30, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2024
Document Transition Report	false
Entity File Number	001-38419
Entity Registrant Name	Arcus Biosciences, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-3898435
Entity Address, Address Line One	3928 Point Eden Way
Entity Address, City or Town	Hayward
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94545
City Area Code	510
Local Phone Number	694-6200
Title of 12(b) Security	Common Stock, Par Value $0.0001 Per Share
Trading Symbol	RCUS
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		91,511,609
Entity Central Index Key	0001724521
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Revenues:
Total revenues	$ 48	$ 32	$ 232	$ 86
Operating expenses:
Research and development (Includes $2, $22, $32 and $89 of net recoveries from a related party)	123	82	347	247
General and administrative	30	30	92	88
Impairment of long-lived assets	0	0	20	0
Total operating expenses	153	112	459	335
Loss from operations	(105)	(80)	(227)	(249)
Non-operating income (expense):
Interest and other income, net	14	12	40	30
Interest expense	(1)	(1)	(2)	(2)
Total non-operating income, net	13	11	38	28
Loss before income taxes	(92)	(69)	(189)	(221)
Income tax expense	0	(2)	0	(5)
Net loss	$ (92)	$ (71)	$ (189)	$ (226)
Net loss per share, basic (in dollars per share)	$ (1)	$ (0.94)	$ (2.11)	$ (3.07)
Net loss per share, diluted (in dollars per share)	$ (1)	$ (0.94)	$ (2.11)	$ (3.07)
Shares used to compute loss per share, basic (in shares)	91.4	74.6	89.6	73.6
Shares used to compute loss per share, diluted (in shares)	91.4	74.6	89.6	73.6
License and Development Services Revenue
Revenues:
Total revenues	$ 41	$ 22	$ 204	$ 58
Other Collaboration Revenue
Revenues:
Total revenues	$ 7	$ 10	$ 28	$ 28

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Revenue from contract with customer, excluding assessed tax	$ 48	$ 32	$ 232	$ 86
Related Party
Research and development expense, net of recoveries	2	22	32	89
License and Development Services Revenue
Revenue from contract with customer, excluding assessed tax	41	22	204	58
License and Development Services Revenue \| Related Party
Revenue from contract with customer, excluding assessed tax	23	18	179	54
Other Collaboration Revenue
Revenue from contract with customer, excluding assessed tax	7	10	28	28
Other Collaboration Revenue \| Related Party
Revenue from contract with customer, excluding assessed tax	$ 7	$ 10	$ 28	$ 28

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Income Statement [Abstract]
Net loss	$ (92)	$ (71)	$ (189)	$ (226)
Other comprehensive income	2	1	1	4
Comprehensive loss	$ (90)	$ (70)	$ (188)	$ (222)

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 201	$ 127
Marketable securities	888	632
Receivable from collaboration partners ($2 and $20 from a related party)	16	38
Prepaid expenses and other current assets	22	34
Total current assets	1,127	831
Long-term marketable securities	2	107
Property and equipment, net	48	51
Other noncurrent assets ($— and $6 from a related party)	75	106
Total assets	1,252	1,095
Current liabilities:
Accounts payable	13	17
Deferred revenue ($93 and $84 to a related party)	105	91
Other current liabilities	97	76
Total current liabilities	215	184
Deferred revenue, noncurrent ($262 and $291 to a related party)	289	307
Long-term debt	47	0
Other noncurrent liabilities	136	142
Commitments
Stockholders’ equity:
Common stock and additional paid-in capital: $0.0001 par value per share; 400.0 shares authorized; 91.5 shares in 2024 and 75.5 shares in 2023 issued and outstanding	1,602	1,311
Accumulated deficit	(1,038)	(849)
Accumulated other comprehensive loss	1	0
Total stockholders’ equity	565	462
Total liabilities and stockholders’ equity	$ 1,252	$ 1,095

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Millions, $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Receivable from collaboration partners, current	$ 16	$ 38
Other noncurrent assets	75	106
Deferred revenue, current	105	91
Deferred revenue, noncurrent	$ 289	$ 307
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	400	400
Common stock, shares issued (in shares)	91.5	75.5
Common stock, shares outstanding (in shares)	91.5	75.5
Related Party
Receivable from collaboration partners, current	$ 2	$ 20
Other noncurrent assets	0	6
Deferred revenue, current	93	84
Deferred revenue, noncurrent	$ 262	$ 291

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Stockholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Equity Award Programs	Common Stock	Common Stock Equity Award Programs	Common stock and additional paid-in capital	Common stock and additional paid-in capital Equity Award Programs	Accumulated deficit	Accumulated other comprehensive loss
Beginning balance, shares at Dec. 31, 2022			72.9
Beginning balance at Dec. 31, 2022	$ 657				$ 1,206		$ (542)	$ (7)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (in shares)				0.2
Issuance of common stock		$ 1				$ 1
Stock-based compensation	19				19
Other comprehensive income (loss)	3							3
Net loss	(80)						(80)
Ending balance, shares at Mar. 31, 2023			73.1
Ending balance at Mar. 31, 2023	600				1,226		(622)	(4)
Beginning balance, shares at Dec. 31, 2022			72.9
Beginning balance at Dec. 31, 2022	657				1,206		(542)	(7)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(226)
Ending balance, shares at Sep. 30, 2023			74.8
Ending balance at Sep. 30, 2023	520				1,291		(768)	(3)
Beginning balance, shares at Mar. 31, 2023			73.1
Beginning balance at Mar. 31, 2023	600				1,226		(622)	(4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (in shares)			1	0.4
Issuance of common stock	20	3			20	3
Stock-based compensation	18				18
Net loss	(75)						(75)
Ending balance, shares at Jun. 30, 2023			74.5
Ending balance at Jun. 30, 2023	566				1,267		(697)	(4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (in shares)			0.2	0.1
Issuance of common stock	5	1			5	1
Stock-based compensation	18				18
Other comprehensive income (loss)	1							1
Net loss	(71)						(71)
Ending balance, shares at Sep. 30, 2023			74.8
Ending balance at Sep. 30, 2023	$ 520				1,291		(768)	(3)
Beginning balance, shares at Dec. 31, 2023	75.5		75.5
Beginning balance at Dec. 31, 2023	$ 462				1,311		(849)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (in shares)			15.2	0.2
Issuance of common stock	228	2			228	2
Stock-based compensation	20				20
Other comprehensive income (loss)	(1)							(1)
Net loss	(4)						(4)
Ending balance, shares at Mar. 31, 2024			90.9
Ending balance at Mar. 31, 2024	$ 707				1,561		(853)	(1)
Beginning balance, shares at Dec. 31, 2023	75.5		75.5
Beginning balance at Dec. 31, 2023	$ 462				1,311		(849)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ (189)
Ending balance, shares at Sep. 30, 2024	91.5		91.5
Ending balance at Sep. 30, 2024	$ 565				1,602		(1,038)	1
Beginning balance, shares at Mar. 31, 2024			90.9
Beginning balance at Mar. 31, 2024	707				1,561		(853)	(1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (in shares)				0.4
Issuance of common stock		1				1
Stock-based compensation	20				20
Net loss	(93)						(93)
Ending balance, shares at Jun. 30, 2024			91.3
Ending balance at Jun. 30, 2024	635				1,582		(946)	(1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (in shares)				0.2
Issuance of common stock		$ 1				$ 1
Stock-based compensation	19				19
Other comprehensive income (loss)	2							2
Net loss	$ (92)						(92)
Ending balance, shares at Sep. 30, 2024	91.5		91.5
Ending balance at Sep. 30, 2024	$ 565				$ 1,602		$ (1,038)	$ 1

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Cash flow from operating activities
Net loss	$ (189)	$ (226)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	59	55
Depreciation and amortization	7	5
Noncash lease expense	5	6
Impairment of long-lived assets	20	0
Amortization of discounts on marketable securities	(19)	(13)
Other items, net	2	2
Changes in operating assets and liabilities:
Receivable from collaboration partners ($18 and $17 from a related party)	32	15
Other assets ($6 and ($4) from a related party)	16	(12)
Accounts payable	(2)	(3)
Deferred revenue (($20) and ($47) to a related party)	(14)	(51)
Other liabilities	13	4
Net cash used in operating activities	(70)	(218)
Cash flow from investing activities
Purchases of marketable securities	(871)	(673)
Proceeds from maturities of marketable securities	726	837
Proceeds from sales of marketable securities	15	20
Purchases of property and equipment	(5)	(18)
Net cash provided by (used in) investing activities	(135)	166
Cash flow from financing activities
Proceeds from issuance of common stock ($228 and $20 from a related party)	228	25
Proceeds from debt issuances, net	47	0
Proceeds from issuance of common stock pursuant to equity award plans	6	5
Payments of employee taxes related to net settlement of equity awards	(2)	0
Net cash provided by financing activities	279	30
Net increase (decrease) in cash, cash equivalents and restricted cash	74	(22)
Cash, cash equivalents and restricted cash at beginning of period	130	209
Cash, cash equivalents and restricted cash at end of period	204	187
Non-cash investing and financing activities:
Unpaid portion of property and equipment purchases included in Accounts payable and Other current liabilities	$ 0	$ 6

Condensed Consolidated Statem_6

Condensed Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Receivable from collaboration partners	$ 32	$ 15
Other assets	16	(12)
Deferred revenue	(14)	(51)
Proceeds from issuance of common stock	228	25
Related Party
Receivable from collaboration partners	18	17
Other assets	(6)	4
Deferred revenue	(20)	(47)
Proceeds from issuance of common stock	$ 228	$ 20

Organization, Liquidity and Cap

Organization, Liquidity and Capital Resources	9 Months Ended
Organization, Liquidity and Capital Resources	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization, Liquidity and Capital Resources	Organization, liquidity and capital resources Organization Arcus Biosciences, Inc. (referred to as "Arcus," "we," "our," "us," or the "Company") is a clinical-stage biopharmaceutical company focused on creating best-in-class therapies. Using our robust and highly efficient drug discovery capability, we have created a significant portfolio of investigational products which are in clinical development, with our most advanced molecule, an anti-TIGIT antibody, now in multiple Phase 3 registrational studies targeting lung and gastrointestinal ("GI") cancers. Our deep portfolio of novel small molecules and enabling antibodies allows us to create highly differentiated therapies, which we are developing to treat multiple large indications. We operate and manage our business as one reportable and operating segment, which is the business of developing and commercializing highly differentiated therapies that have a meaningful impact on patients. Liquidity and Capital Resources As of September 30, 2024, we had cash, cash equivalents and marketable securities of $1.1 billion, which we believe will be sufficient to fund our planned operations for a period of at least twelve months following the date of filing of this report.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
Summary of Significant Accounting Policies	Sep. 30, 2024
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of significant accounting policies Basis of Presentation These interim financial statements should be read in conjunction with the audited Consolidated Financial Statements and the related notes thereto for the year ended December 31, 2023 included in our Annual Report on Form 10-K filed with the Securities and Exchange Commission ("SEC") on February 21, 2024. There have been no significant changes to our summary of significant accounting policies as disclosed in that filing. These interim financial statements have been prepared in accordance with U.S. generally accepted accounting principles ("U.S. GAAP") for interim financial information and include all normal and recurring adjustments that management believes are necessary for a fair presentation of the periods presented. The Condensed Consolidated Balance Sheet as of December 31, 2023 has been derived from audited consolidated financial statements at that date but does not include all of the information required by U.S. GAAP for complete financial statements. Operating results for the nine months ended September 30, 2024 are not necessarily indicative of the results that may be expected for the year ending December 31, 2024 or for any future period. Use of Estimates The preparation of the Condensed Consolidated Financial Statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and related disclosures. We base our estimates on historical experience and on various market-specific and other relevant assumptions that we believe to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Estimates are assessed and updated each period to reflect current information. Actual results may differ materially from those estimates. Recent Accounting Pronouncements There have been no new accounting pronouncements issued or adopted during the period with a significant impact to our financial statements.

Related Party - Gilead Sciences

Related Party - Gilead Sciences, Inc.	9 Months Ended
Related Party - Gilead Sciences, Inc.	Sep. 30, 2024
Related Party Transactions [Abstract]
Related Party - Gilead Sciences, Inc.	Related party - Gilead Sciences, Inc. In 2020, we and Gilead entered into an Option, License and Collaboration Agreement (the "Gilead Collaboration Agreement"), Common Stock Purchase Agreement (the "Stock Purchase Agreement"), and Investor Rights Agreement (the "Investor Rights Agreement"). The Gilead Collaboration Agreement was amended in 2021 (the "First Gilead Collaboration Agreement Amendment"), in 2023 (the "Second Gilead Collaboration Agreement Amendment"), in January 2024 (the "Third Gilead Collaboration Agreement Amendment") and in May 2024 (the "Fourth Gilead Collaboration Agreement Amendment"). The Stock Purchase Agreement was amended in 2021 (the "First Stock Purchase Agreement Amendment"), in 2023 (“the "Second Stock Purchase Agreement Amendment"), and was amended and restated in January 2024 (the "Third Stock Purchase Agreement Amendment"). The Investor Rights Agreement was amended in 2022 (the "First Investor Rights Agreement Amendment") and was amended and restated in January 2024 (the "Second Investor Rights Agreement Amendment"). We refer to these agreements collectively as the Gilead Agreements. Stock Purchase and Investor Rights Agreements In June 2023, under the Second Stock Purchase Agreement Amendment, Gilead purchased 1.0 million shares of our common stock for total gross proceeds of $20 million. In January 2024, under the Third Stock Purchase Agreement Amendment, Gilead purchased 15.2 million shares of our common stock for total gross proceeds of $320 million, of which $87 million was determined to be a premium on the purchase of common stock and allocated to the performance obligations under the Third Gilead Collaboration Agreement Amendment, see Note 5, Revenues. Gilead has the right, at its option until July 2025, to purchase up to a maximum of 35% of the Company’s then-outstanding voting common stock, at a purchase price equal to the greater of a 20% premium to market (based on a trailing five-day average closing price at option exercise) or the $33.54 initial purchase price. Based on the value of our common stock at each contract closing, the right to purchase additional shares had no value. Under the Investor Rights Agreement entered into in 2020 and subsequently amended, Gilead has: the right to designate three members of our board of directors; registration rights for shares that it purchases; and pro rata participation rights in certain future financings. Gilead has exercised its rights to appoint all three board members and we have registered all shares purchased to date. As of September 30, 2024, Gilead held approximately 32.9% of our outstanding common stock arising from purchases in our May 2020 public offering and purchases under the Stock Purchase Agreement and the related amendments. Collaboration Agreements In 2020, we entered into the Gilead Collaboration Agreement, which gave Gilead an exclusive license to develop and commercialize zimberelimab (the anti PD-1 program) in certain markets and time-limited options to acquire exclusive licenses to develop and commercialize any of our then-current and future clinical programs arising during the 10-year collaboration term, contingent upon $100 million option continuation payments payable on each of the second, fourth, sixth and eighth anniversaries of the agreement. Upon closing of the transaction in July 2020, Gilead made an upfront payment of $175 million. In 2021, we entered into the First Gilead Collaboration Agreement Amendment pursuant to which Gilead exercised its option to three programs—providing Gilead with exclusive licenses to develop and commercialize domvanalimab and AB308 (collectively, the anti-TIGIT program), etrumadenant (the adenosine receptor antagonist program) and quemliclustat (the CD73 program), in certain markets—for a total payment of $725 million that was received in 2022. The amendment also (i) provided for a slight reduction in the royalties for these three programs, such that Gilead will pay us tiered royalties as a percentage of revenues ranging from the mid-teens to the low twenties; and (ii) removed the $100 million option continuation payment that was otherwise due on the second anniversary of the Gilead Collaboration Agreement. With respect to domvanalimab, we are also eligible to receive up to $500 million in potential U.S. regulatory approval milestones. Gilead's option, on a program-by-program basis, will expire after a prescribed period following the achievement of a clinical development milestone in such program and our delivery to Gilead of the requisite data package. Gilead may exercise its option to any program at any time prior to expiration of the option and will pay Arcus an option fee of $150 million per program. For each program that Gilead opts in to, both companies will co-develop and equally share global development costs, subject to certain opt-out rights that we have, caps on our spending and related subsequent adjustments, and certain other exceptions. For each program, provided we have not exercised our opt-out rights, we have the option to co-promote in the U.S. with equal sharing of related profits and losses. Gilead has the right to exclusively commercialize outside of the U.S., subject to the rights of our existing partners in any territories and will pay us tiered royalties as a percentage of revenues ranging from the high teens to the low twenties. Under the First Gilead Collaboration Agreement Amendment, Gilead also has option rights to two oncology research programs for which we will lead discovery and early development activities. With respect to these two research programs, Gilead has the right to exercise its option, on a program-by-program basis, either (i) upon our completion of certain IND-enabling activities for an option payment of $60 million or (ii) following the achievement of a clinical development milestone for an option payment of $150 million. In May 2023, we entered into the Second Gilead Collaboration Agreement Amendment pursuant to which we expanded our collaboration to provide Gilead with options to license up to four jointly selected research-stage programs that target inflammatory diseases for which we will lead discovery and early development activities. We will receive an upfront payment of $17.5 million for each initiated program and Gilead will have an option to license each program at two separate, prespecified time points. For the first two research programs, Gilead has the right to exercise its option, on a program-by-program basis, either (i) upon our completion of certain IND-enabling activities for an option payment of $45 million or (ii) following the achievement of a clinical development milestone for an option payment of $150 million. If Gilead exercises its option at the earlier time point for the first two programs, we would be eligible to receive up to $375 million in regulatory and commercial milestone payments as well as tiered royalties for each optioned program. For any other program option exercise by Gilead, the parties would have rights to co-develop and share global development costs and to co-commercialize and share profits in the U.S. for that program. We received a total upfront payment of $35 million for an initial two research programs in June 2023. Gilead’s options to the other two research programs, expires unless the programs are selected prior to May 2025, as amended under the Fourth Gilead Collaboration Agreement Amendment. In January 2024, we entered into the Third Gilead Collaboration Agreement Amendment. The Third Gilead Collaboration Agreement Amendment, among other things, (i) requires Gilead to pay the $100 million option continuation payment due on the fourth anniversary of the Gilead Collaboration Agreement, which was received in the third quarter 2024 (ii) provides that we will operationalize and fund a Phase 3 study we plan to initiate to evaluate quemliclustat in pancreatic cancer subject to Gilead’s right to reinstate the study as part of the parties’ joint development activities upon regulatory approval, (iii) provides that we will solely fund our share of PACIFIC-8, subject to Gilead’s right to reinstate PACIFIC-8 as part of the parties’ joint development activities for the TIGIT Program in the first quarter of 2026, and (iv) provides that we will fund certain other activities. All other terms of the existing collaboration agreements, remain unchanged. As of September 30, 2024, Gilead has licenses to domvanalimab, AB308, etrumadenant, quemliclustat and zimberelimab. For the three months ended September 30, 2024 and 2023, we recognized revenue under the Gilead Agreements of $30 million and $28 million, respectively, and net reimbursements from Gilead recognized as reductions in Research and Development ("R&D") expense of $2 million and $22 million, respectively. For the nine months ended September 30, 2024 and 2023, we recognized revenue under the Gilead Agreements of $207 million and $82 million, respectively, and net reimbursements from Gilead recognized as reductions in R&D expense of $32 million and $89 million, respectively. At September 30, 2024 and December 31, 2023, we had a net receivable of $2 million and $20 million, respectively, recorded in Receivable from collaboration partners on our Condensed Consolidated Balance Sheets. At December 31, 2023, we had $6 million recorded in Other noncurrent assets on our Condensed Consolidated Balance Sheets. For a more detailed discussion on revenues recognized under the Gilead Agreements, see Note 5, Revenues.

License and Collaborations

License and Collaborations	9 Months Ended
License and Collaborations	Sep. 30, 2024
License and Collaboration Agreements [Abstract]
License and Collaborations	License and collaborations We enter into licensing agreements, strategic collaborations and other similar arrangements with third parties for the development and commercialization of certain investigational products. These arrangements may be collaborative and involve two or more parties who are active participants in the operating activities of the collaboration and are exposed to significant risks and rewards depending on the commercial success of the activities. These arrangements may include: non-refundable upfront payments; payments for options to acquire certain rights; potential development and regulatory milestone payments and/or sales-based milestone payments; royalty payments; revenue or profit-sharing arrangements; expense reimbursements; and cost-sharing arrangements. Operating expenses for costs incurred pursuant to these arrangements are reported in their respective expense line items in the Condensed Consolidated Statements of Operations, net of any payments due to or reimbursements due from our collaboration partners, with such reimbursements being recognized at the time the party becomes obligated to pay. Our significant arrangements are discussed below. For a more detailed discussion on revenues recognized under these arrangements, see Note 5, Revenues. Gilead Collaboration See Note 3, Related party - Gilead Sciences, Inc. Taiho Collaboration In 2017, we entered into an agreement with Taiho Pharmaceutical Co., Ltd (“Taiho”) under which we granted them exclusive options to programs arising over a five-year period which ended in September 2022 for an upfront payment of $35 million. Upon an option exercise of a program, Taiho would obtain exclusive development and commercialization rights to investigational products under the program to Japan and certain other Asian countries (excluding China) (the "Taiho Territory"). For each option that Taiho exercises, they will be obligated to make a payment of $3 million to $15 million, depending on the development stage of the optioned program. Upon exercise, Taiho is solely responsible for continued development and commercialization in the Taiho Territory. In addition, for each optioned program we would be eligible to receive clinical and regulatory milestones of up to $130 million and commercial milestone payments of up to $145 million with the achievement of certain sales thresholds in the Taiho Territory. We will also receive royalties ranging from high single-digits to mid-teens on net sales of licensed products in the Taiho Territory. Royalties will be payable by product and country commencing on the first commercial sale and ending upon the later of: (a) 10 years; and (b) expiration of the last-to-expire valid claim of our patents covering the manufacture, use or sale. As of September 30, 2024, Taiho has licenses for the Taiho Territory to (i) etrumadenant (the adenosine receptor antagonist program); (ii) zimberelimab (the anti PD-1 program); (iii) domvanalimab and AB308 (the anti-TIGIT program); and (iv) quemliclustat (the CD73 program), for which Taiho exercised its option in July 2024 for an option payment of $15 million which was received in the third quarter 2024. During 2022, Taiho opted to participate in two global Phase 3 trials of domvanalimab and zimberelimab combinations, STAR-121 and STAR-221, and became obligated to reimburse us for their portion of the global study costs, and to make milestone payments contingent upon successfully satisfying the related clinical milestones. During the quarter ended September 30, 2023, the clinical milestones for domvanalimab and zimberelimab for the STAR-221 study were met and Taiho became obligated to pay us $28 million which has been fully received. In January 2024, the clinical milestones for domvanalimab and zimberelimab for the STAR-121 study were met and Taiho became obligated to pay us $26 million, of which $16 million was received in the quarter ending March 31, 2024 with the remaining $10 million due in the first quarter of 2025. In October 2024, Taiho opted to participate in the global Phase 3 trial of quemliclustat, PRISM-1, and became obligated to reimburse us for their portion of the global study costs, and to make milestone payments totaling $19 million contingent upon successfully satisfying the related clinical milestone. For the three months ended September 30, 2024 and 2023, we recognized revenue under this arrangement of $18 million and $4 million, and net reimbursements from Taiho of $3 million and $2 million, recognized as a reduction in R&D expense. For the nine months ended September 30, 2024 and 2023, we recognized revenue under this arrangement of $25 million and $4 million, and net reimbursements from Taiho of $10 million and $4 million, recognized as a reduction in R&D expense. At September 30, 2024 and December 31, 2023, we had $14 million and $18 million, respectively, related to these agreements recorded in Receivable from collaboration partners on our Condensed Consolidated Balance Sheets. AstraZeneca Collaboration In 2020, we entered into a collaboration with AstraZeneca to evaluate domvanalimab, our investigational anti-TIGIT antibody, in combination with AstraZeneca’s durvalumab in a registrational Phase 3 clinical trial in patients with unresectable Stage 3 non-small cell lung cancer ("NSCLC"), known as the PACIFIC-8 trial. The terms of this agreement were amended in January 2024. Under the collaboration, as amended, each company will retain existing rights to their respective molecules and any future commercial economics. AstraZeneca will conduct the trial, and each company will supply their respective investigational product to support the trial. We may incur milestones of up to $24 million upon the achievement of certain clinical trial progress milestones or under certain circumstances if the agreement is terminated early and we will reimburse AstraZeneca annually for a portion of the trial costs. The portion of the costs that we consider to be unavoidable are accrued as incurred and milestones that are deemed probable of occurring are accrued in advance of the achievement of the milestone. Prior to January 2024, the PACIFIC-8 trial formed part of the Arcus and Gilead joint development program for domvanalimab and our portion of the trial costs were shared with Gilead. At December 31, 2023, we had recognized amounts due from Gilead for these shared costs of $6 million, recorded in Other noncurrent assets on our Condensed Consolidated Balance Sheet. Under the Third Gilead Collaboration Agreement Amendment, we agreed to solely fund our share of PACIFIC-8, subject to Gilead’s right to reinstate PACIFIC-8 as part of the parties’ joint development activities for the TIGIT Program in the first quarter of 2026. For the nine months ended September 30, 2024, we incurred $6 million of R&D expense reflecting our additional share of incurred costs. For the three months ended September 30, 2024 and 2023, we recognized as R&D expense $4 million and $1 million, respectively under this arrangement. For the nine months ended September 30, 2024 and 2023, we recognized as R&D expense $10 million and $6 million, respectively under this arrangement. At September 30, 2024, we have recognized a total liability of $22 million related to our obligation to AstraZeneca, of which $10 million is recorded in Other current liabilities and $12 million is recorded in Other noncurrent liabilities on our Condensed Consolidated Balance Sheets. At December 31, 2023, we have recognized a liability of $11 million, which is recorded in Other noncurrent liabilities on our Condensed Consolidated Balance Sheets. WuXi Biologics License - anti-PD-1 In 2017, we entered into an agreement with WuXi Biologics Ireland Limited ("WuXi Biologics") which, as amended, provides us with exclusive rights to (i) develop, use and manufacture products that include an anti-PD-1 antibody, including zimberelimab, worldwide and (ii) commercialize any such products worldwide, except in Greater China. Under this agreement, as of September 30, 2024, we may incur (i) regulatory milestone payments of up to $50 million, (ii) commercialization milestone payments of up to $375 million, (iii) tiered royalties that range from the high single-digits to low teens on net sales of the licensed products and (iv) fees related to any sublicenses. For the three and nine months ended September 30, 2024 and 2023, we did not have any milestones or royalties due under this arrangement. WuXi Biologics License - anti-CD39 In 2020, we entered into an agreement with WuXi Biologics, under which we obtained the exclusive worldwide license to develop and commercialize anti-CD39 antibodies discovered under this arrangement. Under this agreement, as of September 30, 2024, we may incur additional clinical and regulatory milestone payments of up to $14 million and royalty payments in the low single digits on net sales of the licensed products under this agreement. For the three and nine months ended September 30, 2024, and the three months ended September 30, 2023, we did not have any development milestones due under this arrangement. For the nine months ended September 30, 2023, we incurred development milestones under this arrangement of $1 million, which were recognized as R&D expense. Abmuno License In 2016, we entered into an agreement (the "Abmuno Agreement") with Abmuno Therapeutics LLC ("Abmuno"), under which we obtained the exclusive worldwide license to develop, use, manufacture, and commercialize products that include an anti-TIGIT antibody, including domvanalimab. Under this agreement, as of September 30, 2024 we may incur additional clinical, regulatory and commercialization milestone payments of up to $88 million. For the three and nine months ended September 30, 2024 and 2023, we did not have any milestones due under this arrangement. Exelixis Collaboration In 2023, we entered into a clinical trial collaboration with Exelixis for STELLAR-009, a Phase 1b/2 trial to evaluate casdatifan, our investigational inhibitor of the transcription factor HIF-2⍺, in combination with Exelixis’s zanzalintinib, a next-generation tyrosine kinase inhibitor, in patients with clear cell renal cell carcinoma ("ccRCC"). Under the collaboration, each company will retain existing rights to their respective molecules and any future commercial economics. Exelixis will conduct the STELLAR-009 trial, and each company will supply their respective investigational product to support the trial. We will reimburse Exelixis for a portion of the trial costs. In August 2024, both parties agreed to terminate the agreement and wind down the STELLAR-009 trial. For the three months ended September 30, 2024 and 2023, we recognized R&D expense of $2 million and $1 million, respectively, under this arrangement. For the nine months ended September 30, 2024 and 2023, we recognized R&D expense of $5 million and $1 million, respectively, under this agreement.

Revenues

Revenues	9 Months Ended
Revenues	Sep. 30, 2024
Revenue from Contract with Customer [Abstract]
Revenues	Revenues The following table summarizes our revenues by collaboration, category of revenue, and the method of recognition (in millions): Three Months Ended September 30, Nine Months Ended September 30, Over time Point in time 2024 2023 2024 2023 Gilead Collaboration License and R&D services * $ 25 $ 20 $ 185 $ 57 Access rights * 5 8 22 25 Taiho Collaboration License revenue * 15 — 15 — R&D services * 3 4 10 4 Total revenues $ 48 $ 32 $ 232 $ 86 Revenues from Gilead accounted for 63% and 88% of Total revenues for the three months ended September 30, 2024 and 2023, respectively and 89% and 95% of Total revenues for the nine months ended September 30, 2024 and 2023, respectively. The following table summarizes the revenue recognized as a result of changes in the deferred revenue balance (in millions): Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Revenue recognized from amounts in deferred revenue at the beginning of the period $ 33 $ 28 $ 212 $ 79 At September 30, 2024 and December 31, 2023, we had $394 million and $398 million of deferred revenue remaining on our Condensed Consolidated Balance Sheets, respectively, allocated between current and noncurrent based on the expected timing of future recognition. Revenue from the Gilead Collaboration In 2021, we entered into the First Gilead Collaboration Agreement Amendment, which we determined represented a contract modification which was accounted for as a termination of the existing contract and the creation of a new contract. On January 29, 2024, we entered into the Third Gilead Collaboration Agreement Amendment, which we determined was a change in scope and price of the original contract and we accounted for this contract modification as both a modification of the existing contract and the creation of a new contract. Under the applicable accounting rules for such contract modifications, we did not adjust the accounting for completed performance obligations that were distinct from the modified goods or services. However, we adjusted revenue previously recognized to reflect the effect of the contract modification due to the updated estimated transaction price allocated to the partially satisfied performance obligations and the updated measure of progress as of the modification date. Accordingly, we allocated the transaction price to the remaining performance obligations (both from the existing contract and the modification) and recognized a cumulative catch-up to revenue of $107 million based on the updated transaction price and measure of progress for the partially satisfied performance obligations. This cumulative catch-up reduced net loss per share, basic and diluted, in the nine months ended September 30, 2024 by $1.19 (see Note 3, Related party - Gilead Sciences, Inc.). The following table summarizes the transaction price (in millions): Transaction price Amount Premium from Third Stock Purchase Agreement Amendment $ 87 Option continuation payment received in the third quarter of 2024 100 Deferred revenue as of January 29, 2024 335 Total transaction price $ 522 Our assessment of the updated transaction price for the Third Gilead Collaboration Agreement Amendment included an analysis of amounts we expected to receive, which at contract amendment consisted of: the $100 million option continuation payment that Gilead committed to and paid in the third quarter of 2024 for continued access to our pipeline; $87 million allocated from the premium from the Third Stock Purchase agreement; and $335 million deferred revenue remaining from the First Gilead Collaboration Agreement Amendment effective December 2021. We determined the entire $522 million to be the allocable transaction price as of the amendment closing date, due to the history of timely payments by Gilead. The following table summarizes the allocation of the transaction price to the performance obligations (in millions): Allocation to performance obligations Distinct Combined Amount Etrumadenant - License and R&D services * $ 210 Quemliclustat - License and R&D services * 168 Domvanalimab - R&D services * 33 Access rights * 57 Option continuation periods * 20 Rights to certain studies * 34 Total allocated transaction price $ 522 We accounted for each performance obligation as follows: Etrumadenant - License and R&D Services Under the Gilead Collaboration Agreement, Gilead obtained an option to the exclusive rights to our adenosine receptor program, etrumadenant, in exchange for an option payment of $250 million, if exercised. Effective December 2021, under the First Gilead Collaboration Agreement Amendment, Gilead exercised the option and obtained an exclusive license to etrumadenant and we were also obligated to perform further R&D services for Gilead related to etrumadenant. We determined that the license and R&D services were combined at inception of the agreement based on an evaluation of the delivery of the license, due to the early stage of the technology and the specialized nature of our know-how. We determined the standalone selling price of the license using a discounted cash flow method and the R&D services using an expected cost-plus margin approach. We recognize the amounts allocated to the combined license and services as the performance obligation is satisfied, calculated as an estimated percentage of completion based on management's estimated total effort for the program. Prior to the closing of the Third Gilead Collaboration Agreement Amendment, we had $129 million of deferred revenue on our Condensed Consolidated Balance Sheet related to this performance obligation. Effective January 29, 2024, under the Third Gilead Collaboration Agreement Amendment, this performance obligation was partially satisfied and there were no changes to the scope of the related R&D service obligation as a result of the amendment. We allocated the updated transaction price to this performance obligation based on the standalone selling price and adjusted revenue based on an updated measure of progress, which resulted in a cumulative catch-up of revenue of $14 million. We recognized revenue of $9 million and $21 million for the three months ended September 30, 2024 and 2023, respectively, and $36 million (including the cumulative catch-up) and $39 million for the nine months ended September 30, 2024 and 2023, respectively, within License and development services revenue in our Condensed Consolidated Statements of Operations related to this performance obligation. At September 30, 2024 and December 31, 2023, we had $176 million and $133 million, respectively, of deferred revenue remaining on our Condensed Consolidated Balance Sheets related to this performance obligation. Quemliclustat - License and R&D Services Under the Gilead Collaboration Agreement, Gilead obtained an option to the exclusive rights to our CD73 program, quemliclustat, in exchange for an option payment of $200 million, if exercised. Effective December 2021, under the First Gilead Collaboration Agreement Amendment, Gilead exercised the option and obtained an exclusive license to quemliclustat and we were also obligated to perform further R&D services for Gilead related to quemliclustat. We determined that the license and R&D services were combined at inception of the agreement based on an evaluation of the delivery of the license, due to the early stage of the technology and the specialized nature of our know-how. We determined the standalone selling price of the license using a discounted cash flow method and the R&D services using an expected cost-plus margin approach. We recognize the amounts allocated to the combined license and services as the performance obligation is satisfied, calculated as an estimated percentage of completion based on management's estimated total effort for the program. Prior to the closing of the Third Gilead Collaboration Agreement Amendment, we had $130 million of deferred revenue on our Condensed Consolidated Balance Sheet related to this performance obligation. Effective January 29, 2024, under the Third Gilead Collaboration Agreement Amendment, this performance obligation was partially satisfied and there was a reduction to the scope of the related R&D service obligation as a result of the amendment. Specifically, the amendment provides that we will independently initiate, operationalize and fund a Phase 3 study to evaluate quemliclustat in pancreatic cancer, which reduces our estimated obligation to perform further R&D services for Gilead related to quemliclustat under the collaboration. We allocated the updated transaction price to this performance obligation based on the standalone selling price and adjusted revenue based on an updated measure of progress which resulted in cumulative catch-up of revenue of $88 million. We recognized revenue of $13 million for the three months ended September 30, 2024 and a reversal of revenue of $4 million for the three months ended September 30, 2023 due to the changes in the total estimated effort to be incurred in the future to satisfy the performance obligations. We recognized revenue of $132 million (including the cumulative catch-up) and $11 million for the nine months ended September 30, 2024 and 2023, respectively, within License and development services revenue in our Condensed Consolidated Statements of Operations related to this performance obligation. At September 30, 2024 and December 31, 2023, we had $39 million and $132 million, respectively, of deferred revenue remaining on our Condensed Consolidated Balance Sheets related to this performance obligation. Domvanalimab - R&D Services Under the First Gilead Collaboration Agreement Amendment, we determined that we retain a separate performance obligation to perform further R&D services for Gilead related to domvanalimab. The standalone selling price of this obligation was determined using an expected cost-plus margin approach. We recognize the amounts allocated to these services as the performance obligation is satisfied, calculated as an estimated percentage of completion based on management's estimated total effort for the program. Prior to the closing of the Third Gilead Collaboration Agreement Amendment, we had $25 million of deferred revenue on our Condensed Consolidated Balance Sheet related to this performance obligation. Effective January 29, 2024, under the Third Gilead Collaboration Agreement Amendment, this performance obligation was partially satisfied and there were no significant changes to the scope of this obligation as a result of the amendment. We allocated the updated transaction price to this performance obligation based on the standalone selling price and adjusted revenue based on an updated measure of progress which resulted in cumulative catch-up of revenue of $5 million. We recognized revenue of $1 million and $1 million for the three months ended September 30, 2024 and 2023, respectively, and $11 million (including the cumulative catch-up) and $3 million for the nine months ended September 30, 2024 and 2023, respectively, within License and development services revenue in our Condensed Consolidated Statements of Operations related to this performance obligation. At September 30, 2024 and December 31, 2023, we had $23 million and $25 million, respectively, of deferred revenue remaining on our Condensed Consolidated Balance Sheets related to this performance obligation. Access Rights and Option Continuation Periods Under the First Gilead Collaboration Agreement Amendment, Gilead has exclusive access to our current programs as well as the future programs for a period of ten years, contingent upon option continuation payments totaling $300 million, consisting of a $100 million payment on each of the fourth, sixth, and eighth anniversaries of the Gilead Collaboration Agreement. Prior to the closing of the Third Gilead Collaboration Agreement Amendment, we had $51 million of deferred revenue on our Condensed Consolidated Balance Sheet related to these performance obligations. Effective January 29, 2024, under the Third Gilead Collaboration Agreement Amendment, Gilead agreed to pay the $100 million option continuation payment due on the fourth anniversary of the Gilead Collaboration Agreement, which occurred and was received in the third quarter of 2024, and we included this payment in the transaction price. By exercising this right Gilead’s exclusive access to our current programs as well as any future programs is extended to 2026. We determined that as of the closing date of January 29, 2024, Gilead is not obligated to make the remaining contingent payments totaling $200 million due on the sixth and eighth anniversaries of the Gilead Collaboration Agreement and accordingly, we have excluded these payments from the transaction price. Failure to pay the non-obligatory option continuation payments will result in Gilead’s loss of certain rights to access and obtain licenses to the programs arising from our R&D pipeline. The standalone selling price of the ongoing R&D pipeline access and the option continuation material rights were determined using an expected cost-plus margin approach, with the option continuation material rights probability-adjusted for the likelihood of exercise. We use a time-elapsed input method to measure progress toward satisfying the access rights performance obligation, which is the method we believe most faithfully depicts the Company's performance in transferring the promised services during the time period in which Gilead has access to our R&D pipeline. Accordingly, the revenue allocated to the initial four-year access rights performance obligation is being recognized using this input method over the remaining period through July 2024, and for the access rights continuation, over the two-year period commencing July 2024. For the remaining access rights option continuation periods commencing on the sixth, and eighth anniversaries of the agreement, if Gilead elects to exercise their option, we will recognize the revenue allocated to that option together with the $100 million continuation payment over the new minimum access period or immediately if the option lapses. We recognized revenue of $5 million and $8 million associated with the access rights performance obligation for each of the three months ended September 30, 2024 and 2023, respectively, and $22 million and $25 million associated with the access rights performance obligation for each of the nine months ended September 30, 2024 and 2023, respectively, within Other collaboration revenue in our Condensed Consolidated Statements of Operations related to these performance obligations. At September 30, 2024 and December 31, 2023, we had $58 million and $54 million, respectively, of deferred revenue on our Condensed Consolidated Balance Sheets related to these performance obligations. Rights to Certain Studies Effective January 29, 2024, under the Third Gilead Collaboration Agreement Amendment, we will solely fund, certain studies, but Gilead retains exclusive rights to reinstate into the collaboration each study at specified time-points for a payment. We have determined that these are material rights and we estimated the standalone selling price of these performance obligations using a discounted cash flow method probability-adjusted for the likelihood of exercise. We will recognize the amount allocated to each right if and when the related study is reinstated into the parties' co-development plans or if the option lapses. At September 30, 2024, we had $34 million of deferred revenue remaining on our Condensed Consolidated Balance Sheet related to these performance obligations. Inflammation Programs - R&D Services In addition to the amendments noted above, in May 2023, we entered into the Second Gilead Collaboration Agreement Amendment pursuant to which we expanded our collaboration to provide Gilead with options to license up to four jointly selected research-stage programs that target inflammatory diseases for which we will lead discovery and early development activities (see Note 3, Related party - Gilead Sciences, Inc., for more information). In June 2023, we received a total upfront payment of $35 million for an initial two jointly selected research-stage programs. We determined that the Second Gilead Collaboration Agreement Amendment represented a separate contract and, at the amendment closing date, we allocated the transaction price of $35 million to the performance obligations created as of the date of this amendment. The following table summarizes the allocation of the transaction price to the performance obligations (in millions): Allocation to performance obligations Distinct Amount Inflammation target 1 - R&D services * $ 18 Inflammation target 2 - R&D services * 17 Total allocated transaction price $ 35 We determined that we have separate performance obligations to perform R&D services for Gilead related to discovery and early development activities for each research program for which they have made an upfront payment. The standalone selling price of these obligations were determined using an expected cost-plus margin approach. We recognize the amounts allocated to these services as the performance obligation is satisfied, calculated as an estimated percentage of completion based on management's estimated total effort for the program. The options to acquire additional licenses or services did not result in additional performance obligations because they did not provide a material right at contract inception, primarily due to the very early stages of the programs. We recognized revenue of $2 million for the three months ended September 30, 2024 and 2023, and $6 million and $3 million for the nine months ended September 30, 2024 and 2023, respectively, within Other collaboration revenue in our Condensed Consolidated Statements of Operations related to these performance obligations. At September 30, 2024 and December 31, 2023, we had $25 million and $31 million, respectively, of deferred revenue remaining on our Condensed Consolidated Balance Sheets related to these performance obligations. Revenue from the Taiho Collaboration Quemliclustat - License In July 2024, Taiho exercised its option under the agreement we entered into in 2017 and obtained an exclusive license for quemliclustat (the CD73 program) for the Taiho Territory for an option payment of $15 million which was received in the third quarter 2024. We determined that this license was the only performance obligation and we recognized upon delivery the full $15 million of revenue in the quarter ended September 30, 2024 within License and development services revenue in our Condensed Consolidated Statements of Operations. Domvanalimab and Zimberelimab - R&D Services During 2022, Taiho opted to participate in two global Phase 3 trials of domvanalimab and zimberelimab combinations, STAR-121 and STAR-221, and became obligated to make certain milestone payments contingent upon successfully satisfying the related clinical milestones. During the quarter ended September 30, 2023, the clinical milestones for domvanalimab and zimberelimab for the STAR-221 study were met and Taiho became obligated to pay us $28 million which was fully received as of September 30, 2024. In January 2024, the clinical milestones for domvanalimab and zimberelimab for the STAR-121 study were met and Taiho became obligated to pay us $26 million of which $16 million has been received as of September 30, 2024 with the remaining $10 million due in the first quarter of 2025. We determined that we have separate performance obligations to perform R&D services for Taiho related to the global development activities for each study in support of the Taiho Territory and that the agreement for each study represented a separate contract at standalone selling price. The standalone selling price of these obligations were determined using an expected cost-plus margin approach. We recognize the amounts for these services as each performance obligation is satisfied, calculated as an estimated percentage of completion based on the estimated total effort for the programs. We recognized revenue of $3 million and $4 million for the three months ended September 30, 2024 and 2023, respectively, and $10 million and $4 million for the nine months ended September 30, 2024 and 2023, respectively, within License and development services revenue in our Condensed Consolidated Statements of Operations related to these performance obligations. At September 30, 2024 and December 31, 2023, we had $39 million and $23 million, respectively, of deferred revenue remaining on our Condensed Consolidated Balance Sheets related to these performance obligations, allocated between current and noncurrent based on the expected timing of future recognition. Capitalized Costs to Obtain Contracts We incurred $8 million of costs on January 29, 2024 to obtain the Third Gilead Collaboration Agreement Amendment, Third Stock Purchase Agreement Amendment and the Second Investor Rights Agreement Amendment, which consisted of consultant fees that were payable upon the successful completion of the agreements. We determined that $5 million of these costs were related to the Third Stock Purchase Agreement Amendment which were recognized as offering costs in additional paid-in capital. The remaining costs were combined with $3 million in capitalized costs that remained from the initial Gilead Collaboration Agreement and subsequent amendments, and the total was allocated to the various remaining performance obligations, to be recognized as the underlying performance obligations are satisfied and revenue is recognized. For each of the three months ended September 30, 2024 and 2023, expense related to these capitalized costs in was recognized in General and administrative ("G&A") expense was not significant. For the nine months ended September 30, 2024 and 2023, we recognized expense of $3 million and $1 million, respectively, related to these capitalized costs in G&A expense. At September 30, 2024 and December 31, 2023, we had $3 million in capitalized costs to obtain the contracts, allocated between Prepaid expenses and other current assets and Other noncurrent assets in our Condensed Consolidated Balance Sheets based on the expected timing of future recognition.

Income Taxes

Income Taxes	9 Months Ended
Income Taxes	Sep. 30, 2024
Income Tax Disclosure [Abstract]
Income Taxes	Income taxes The income tax provision or benefit for interim periods is determined using an estimate of our annual effective tax rate, adjusted for discrete items, if any, that are taken into consideration in the relevant period. Each quarter, we update the estimate of the annual effective tax rate, and if the estimated tax rate changes, we record a cumulative adjustment to the provision or benefit. We did not record a provision for income taxes for the three and nine months ended September 30, 2024 because of a forecasted full year net operating loss ("NOL"). The income tax expense was $2 million and $5 million for the three and nine months ended September 30, 2023, with an effective tax rate of (2.4%) and (2.2%), respectively. The year-over-year decrease in the income tax provision was due to a decrease in taxable income. For the year ended December 31, 2023, we had taxable income compared to book losses before income taxes due to the timing of recognition of deferred revenue for tax purposes and the effects of the mandatory capitalization and amortization of R&D expenses starting in 2022, as required by the 2017 Tax Cuts and Jobs Act. The effective tax rate differs from the U.S. statutory tax rate primarily due to the valuation allowances on our deferred tax assets and state income taxes. As of September 30, 2024 and December 31, 2023, we have provided a valuation allowance against U.S. federal and state deferred tax assets. We continue to evaluate the realizability of deferred tax assets and the related valuation allowance. If our assessment of the deferred tax assets or the corresponding valuation allowance were to change, we would record the related adjustment to income during the period in which we make the determination. We recognize interest and penalties associated with uncertain tax benefits as part of the income tax provision. To date, we have not recognized any interest and penalties, nor have we accrued for or made payments for interest and penalties. We have not been audited by the Internal Revenue Service, any state or foreign tax authority. We are subject to taxation in the U.S. and in Australia. Due to NOL and research credit carryforwards, all of our tax years, from 2015 to 2023, remain open to U.S. federal and California state tax examinations. In addition, our fiscal years from 2019 to 2023 are open to examination in Australia.

Net Loss Per Share

Net Loss Per Share	9 Months Ended
Net Loss Per Share	Sep. 30, 2024
Earnings Per Share [Abstract]
Net Loss Per Share	Net loss per share The following table summarizes potentially dilutive securities excluded from the computation of diluted net loss per share calculations because they would have been antidilutive (in millions): September 30, 2024 September 30, 2023 Common stock options issued and outstanding 15.5 13.7 Restricted stock units issued 3.0 1.9 Employee Stock Purchase Plan shares 0.2 0.2 Total potential dilutive securities 18.7 15.8 We have also excluded the effect of Gilead’s right to purchase additional shares of our common stock from the calculation as these rights had no intrinsic value at either September 30, 2024 or 2023.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
Stock-Based Compensation	Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-based compensation Stock-based compensation expense The following table reflects the components of stock-based compensation expense recognized in our Condensed Consolidated Statements of Operations (in millions): Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Research and development $ 9 $ 8 $ 29 $ 26 General and administrative 10 10 30 29 Total stock-based compensation $ 19 $ 18 $ 59 $ 55

Cash, Cash Equivalents and Mark

Cash, Cash Equivalents and Marketable Securities	9 Months Ended
Cash, Cash Equivalents and Marketable Securities	Sep. 30, 2024
Cash, Cash Equivalents and Marketable Securities [Abstract]
Cash, Cash Equivalents and Marketable Securities	Cash, cash equivalents and marketable securities The following table summarizes the amortized cost, gross unrealized gains and losses and the fair value of our cash, cash equivalents and marketable securities, all of which are considered available for sale, by type of securities (in millions): Types of securities as of September 30, 2024 Amortized Cost Unrealized Gain Unrealized Loss Fair Value Money market funds $ 134 $ — $ — $ 134 U.S. treasury securities 258 — — 258 Corporate securities and commercial paper 667 1 — 668 U.S. government agency securities 9 — — 9 Certificate of deposit 22 — — 22 Total cash, cash equivalents and marketable securities $ 1,090 $ 1 $ — $ 1,091 Types of securities as of December 31, 2023 Amortized Cost Unrealized Gain Unrealized Loss Fair Value Money market funds $ 85 $ — $ — $ 85 U.S. treasury securities 213 1 (1) 213 Corporate securities and commercial paper 471 — — 471 U.S. government agency securities 90 — — 90 Certificate of deposit 7 — — 7 Total cash, cash equivalents and marketable securities $ 866 $ 1 $ (1) $ 866 The following table summarizes the fair values of our cash, cash equivalents and marketable securities by location in the Condensed Consolidated Balance Sheets and contractual maturity (in millions): Location in Condensed Consolidated Balance Sheets Contractual Maturity September 30, 2024 December 31, 2023 Cash and cash equivalents — $ 201 $ 127 Marketable securities Within one year 888 632 Long-term marketable securities Between one and three years 2 107 Total cash, cash equivalents and marketable securities $ 1,091 $ 866 Realized gains or losses recognized on the sale of available-for-sale marketable securities were not material for the three and nine months ended September 30, 2024 and 2023. Realized gains and losses are included in Interest and other income, net, in the Condensed Consolidated Statements of Operations. The cost of a security sold is determined using the specific-identification method. We limit the credit risk associated with our investments by placing them with banks and institutions we believe are highly credit worthy and investing in highly rated investments. We held a total of 21 and 105 positions in securities which were in unrealized loss positions as of September 30, 2024 and December 31, 2023, respectively. We do not intend to sell our securities with unrealized loss positions and have concluded we will not be required to sell the securities before recovery of the amortized cost for the investment at maturity. No credit related losses have been recognized for any of the periods presented. The following table provides a reconciliation of cash, cash equivalents, and restricted cash within the Condensed Consolidated Balance Sheets to the total shown in the Condensed Consolidated Statements of Cash Flows (in millions): As of September 30, 2024 2023 Cash and cash equivalents $ 201 $ 184 Restricted cash (included in Other noncurrent assets) 3 3 Total cash, cash equivalents and restricted cash $ 204 $ 187 Restricted cash at September 30, 2024 and 2023 represents cash balances held as security in connection with our facility lease agreements.

Condensed Consolidated Balanc_3

Condensed Consolidated Balance Sheet Components	9 Months Ended
Condensed Consolidated Balance Sheet Components	Sep. 30, 2024
Balance Sheet Related Disclosures [Abstract]
Condensed Consolidated Balance Sheet Components	Condensed consolidated balance sheet components Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consisted of the following (in millions): September 30, 2024 December 31, 2023 Prepaid expenses and other assets $ 17 $ 30 Accrued interest receivable 5 4 Total prepaid expenses and other current assets $ 22 $ 34 Other Current Liabilities Other current liabilities consisted of the following (in millions): September 30, 2024 December 31, 2023 Accrued research and development $ 57 $ 36 Accrued personnel expenses 27 26 Current portion of lease liabilities 11 11 Other 2 3 Total other current liabilities $ 97 $ 76

Long-term Debt

Long-term Debt	9 Months Ended
Long-term Debt	Sep. 30, 2024
Debt Disclosure [Abstract]
Long-term Debt	Long-term deb t The following table summarizes our borrowings (in millions): September 30, 2024 December 31, 2023 Long-term debt, non-current (Contractual maturity 2029) $ 50 $ — Unamortized discounts and issuance costs (3) — Total long-term debt $ 47 $ — On August 27, 2024, we and Hercules Capital, Inc. (“Hercules”) entered into a loan and security agreement (the "Hercules Agreement"), under which Hercules agreed to lend us up to $250 million in term loans in various tranches subject to minimum draw requirements for each tranche. Under the terms of this agreement, $50 million was drawn at closing and an additional $100 million is committed and fully available at our sole option in minimum increments of $25 million. A second tranche of $100 million will be available subject to future approval by Hercules. The Hercules Agreement has an initial maturity date of September 1, 2029 which is extendable by 12 months, at our discretion subject to the achievement of certain regulatory milestones related to our product candidates. Repayment of the principal amount will be in 13 monthly installments commencing September 1, 2028, if not extended. The term loans have an interest only period for the first 48 months from the agreement date and bear interest at a rate equal to the greater of (i) 10.45% or (ii) the prime rate The Hercules Agreement contains customary affirmative and negative covenants, including covenants that limit or restrict our ability to incur liens, incur indebtedness, make investments, pay dividends, merge or consolidate, dispose of assets, and enter into transactions with affiliates, subject to customary exceptions. We are also required to maintain a minimum cash balance of 50% of the funded amount if our market capitalization were to fall below a certain threshold which will be reduced in the event of certain regulatory approvals of our product candidates. We do not have covenant requirements associated with this agreement until October 1, 2026. The Hercules Agreement is secured by a first priority security interest in substantially all of our assets, excluding intellectual property. The Hercules Agreement also contains customary events of default terms, including payment defaults, breaches of covenants, bankruptcy and insolvency events, cross-defaults to other indebtedness, material adverse events, and the occurrence of a change of control. Upon the occurrence of an event of default, Hercules may declare all outstanding obligations under the Hercules Agreement to be immediately due and payable and exercise any or all of its rights and remedies, including foreclosure on the collateral securing the term loans. The aggregate future minimum payments including principal payments and the end of term charge, due under the Hercules Agreement, are as follows (in millions): Maturity Date Amount 2028 $ 15 2029 39 Total payments $ 54 During the three and nine months ended September 30, 2024, we recognized $1 million of interest expense, including amortization of the debt discount and issuance costs which was at an effective interest rate of 13.39%. As of September 30, 2024, we had borrowed $50 million under the Hercules Agreement and had $200 million of additional borrowing capacity, of which $100 million is subject to additional approval by Hercules.

Leases

Leases	9 Months Ended
Leases	Sep. 30, 2024
Leases [Abstract]
Leases	Leases The following table summarizes our cash and non-cash information related to our operating leases (in millions): Nine Months Ended September 30, 2024 2023 Cash paid for amounts included in measurement of lease liabilities $ 12 $ 12 Cash received from tenant improvement allowances $ — $ 8 Recognition of tenant improvement allowance receivable included in Other current liabilities $ — $ 4 In the first quarter of 2024, we evaluated our plans for a portion of our office space that we expected to sublease, and identified indicators of impairment to certain right-of-use assets associated with the leased space where the asset value was determined to be non-recoverable based upon a discounted cash flow analysis, resulting in an impairment charge of $20 million for the three months ended March 31, 2024 and the nine months ended September 30, 2024. In the second quarter of 2024, we entered into a sublease for a portion of our office space which is expected to commence by the end of 2024 or early 2025, and extends through 2031. As of September 30, 2024 and December 31, 2023, we have provided deposits for letters of credit totaling $3 million to secure our obligations under our leases, which are included in Other noncurrent assets on the Condensed Consolidated Balance Sheets.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
Stockholders' Equity	Sep. 30, 2024
Stockholders' Equity Note [Abstract]
Stockholders' Equity	Stockholders' equity Common Stock Gilead Stock Purchase Agreement On June 27, 2023, under the Second Stock Purchase Agreement, Gilead purchased 1.0 million shares of our common stock at the closing day purchase price of $19.26 per share for total gross proceeds of $20 million. On January 29, 2024, under the Third Stock Purchase Agreement Amendment, Gilead purchased 15.2 million shares of our common stock at a price of $21.00 per share for total gross proceeds of $320 million. Of the $320 million equity investment, $87 million was determined to be a premium on the purchase of common stock and allocated to the performance obligations created by the Third Gilead Collaboration Agreement Amendment, see Note 5, Revenues. Net proceeds from Gilead's equity investment were $228 million after allocating the premium and deducting direct offering expenses of $5 million. At-the-Market Facility In August 2023, we issued and sold 0.2 million shares of our common stock under this agreement for total net proceeds of $5 million.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
Fair Value Measurements	Sep. 30, 2024
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair value measurements We determine the fair value of financial and non-financial assets and liabilities using the fair value hierarchy, which establishes three levels of inputs that may be used to measure fair value, as follows: • Level 1 inputs include unadjusted quoted prices in active markets for identical assets or liabilities; • Level 2 inputs include observable inputs other than Level 1 inputs, such as quoted prices for similar assets or liabilities; quoted prices for identical or similar assets or liabilities in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the asset or liability; and • Level 3 inputs include unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the underlying asset or liability. Our Level 3 assets and liabilities include those whose fair value measurements are determined using pricing models, discounted cash flow methodologies or similar valuation techniques and significant management judgment or estimation. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The following tables summarize the types of assets and liabilities measured at fair value on a recurring basis by level within the fair value hierarchy (in millions): Fair value measurement as of September 30, 2024 Level 1 Level 2 Level 3 Total Assets Money market funds $ 134 $ — $ — $ 134 U.S. treasury securities — 258 — 258 Corporate securities and commercial paper — 668 — 668 U.S. government agency obligations — 9 — 9 Certificate of deposit — 22 — 22 Total assets measured at fair value $ 134 $ 957 $ — $ 1,091 Liabilities Liability for sale of future royalties $ — $ — $ 21 $ 21 Total liabilities measured at fair value $ — $ — $ 21 $ 21 Fair value measurement as of December 31, 2023 Level 1 Level 2 Level 3 Total Assets Money market funds $ 85 $ — $ — $ 85 U.S. treasury securities — 213 — 213 Corporate securities and commercial paper — 471 — 471 U.S. government agency obligations — 90 — 90 Certificate of deposit — 7 — 7 Total assets measured at fair value $ 85 $ 781 $ — $ 866 Liabilities Liability for sale of future royalties $ — $ — $ 19 $ 19 Total liabilities measured at fair value $ — $ — $ 19 $ 19 Liability for sale of future royalties In 2021, we entered into an agreement with BVF Partners L.P. ("BVF"), under which BVF funded the discovery and development of compounds for the treatment of inflammatory diseases (the "BVF Program") for $15 million in non-refundable payments which were paid in 2021 and 2022. In return, we are obligated to: perform R&D activities in the BVF Program; make contingent payments upon the achievement of certain clinical and regulatory milestones of up to $73 million or $160 million depending on whether the BVF Program is solely developed by us or with Gilead if they opt-in under the Gilead Collaboration Agreement; and pay mid- to high-single digit royalties on any net product sales generated by the BVF Program. We account for the agreement with BVF as a liability primarily because we have significant continuing involvement in generating the cash flows due to BVF. The liability is recorded at fair value by using probability-adjusted discounted cash flows and is revalued each reporting period until the related contingencies have been resolved. The fair value measurement is based on significant unobservable inputs that are reviewed quarterly by management and include, as applicable, estimated probabilities and the timing of achieving specified development, regulatory and commercial milestones as well as estimated annual sales. Significant changes that increase or decrease the probabilities of achieving the related development, regulatory and commercial events or that shorten or lengthen the time required to achieve such events or that increase or decrease estimated annual sales would result in corresponding increases or decreases in the fair values of the obligations, as applicable. Changes in the fair value of this liability related to interest accretion are recognized in Non-operating income (expense) in the Condensed Consolidated Statements of Operations. During the second quarter of 2023, new preclinical information from our BVF Program led to revised assumptions which decreased the estimated probabilities of success and delayed the projected timing of achieving specified development, regulatory and commercial milestones and commercial sales. These changes in estimates are accounted for prospectively and resulted in a decrease in the imputed effective interest rate on the unamortized portion of the liability to 10.1% commencing with the quarter ended June 30, 2023, compared to 20.6% for the quarters ended March 31, 2023 and prior. The impact of this change on the non-cash interest expense for the nine months ended September 30, 2024 was not material when compared to the prior period. The liability for sale of future royalties is reported in Other noncurrent liabilities in the Condensed Consolidated Balance Sheets and changes were as follows (in millions): Nine Months Ended September 30, 2024 2023 Beginning balance $ 19 $ 17 Interest accretion 2 2 Ending balance $ 21 $ 19 Long-term debt As of September 30, 2024, the estimated fair value of our long-term debt approximated the carrying amount. The fair value of the long-term debt was estimated for disclosure purposes only and was determined based on other inputs that are observable, and thus categorized as Level 2 in the fair value hierarchy.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Millions	3 Months Ended						9 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Millions	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Pay vs Performance Disclosure
Net loss	$ (92)	$ (93)	$ (4)	$ (71)	$ (75)	$ (80)	$ (189)	$ (226)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended	9 Months Ended
Insider Trading Arrangements	Sep. 30, 2024 shares	Sep. 30, 2024 shares
Trading Arrangements, by Individual
Material Terms of Trading Arrangement		The adoption, modification or termination of contracts, instructions or written plans for the purchase or sale of our securities by our Section 16 officers and directors for the three months ended September 30, 2024, which are intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act, were as follows: Name and Title Action Date Total Shares to be Sold Expiration Date Juan Jaen President Adoption August 12, 2024 265,993 November 14, 2025 Jennifer Jarrett Chief Operating Officer Adoption September 3, 2024 90,263 June 13, 2025
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Juan Jaen [Member]
Trading Arrangements, by Individual
Name	Juan Jaen
Title	President
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	August 12, 2024
Expiration Date	November 14, 2025
Arrangement Duration	459 days
Aggregate Available	265,993	265,993
Jennifer Jarrett [Member]
Trading Arrangements, by Individual
Name	Jennifer Jarrett
Title	Chief Operating Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	September 3, 2024
Expiration Date	June 13, 2025
Arrangement Duration	283 days
Aggregate Available	90,263	90,263

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
Summary of Significant Accounting Policies (Policies)	Sep. 30, 2024
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation These interim financial statements should be read in conjunction with the audited Consolidated Financial Statements and the related notes thereto for the year ended December 31, 2023 included in our Annual Report on Form 10-K filed with the Securities and Exchange Commission ("SEC") on February 21, 2024. There have been no significant changes to our summary of significant accounting policies as disclosed in that filing. These interim financial statements have been prepared in accordance with U.S. generally accepted accounting principles ("U.S. GAAP") for interim financial information and include all normal and recurring adjustments that management believes are necessary for a fair presentation of the periods presented. The Condensed Consolidated Balance Sheet as of December 31, 2023 has been derived from audited consolidated financial statements at that date but does not include all of the information required by U.S. GAAP for complete financial statements.
Use of Estimates	Use of Estimates The preparation of the Condensed Consolidated Financial Statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and related disclosures. We base our estimates on historical experience and on various market-specific and other relevant assumptions that we believe to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Estimates are assessed and updated each period to reflect current information. Actual results may differ materially from those estimates.
Recent Accounting Pronouncements	Recent Accounting Pronouncements There have been no new accounting pronouncements issued or adopted during the period with a significant impact to our financial statements.

Revenues (Tables)

Revenues (Tables)	9 Months Ended
Revenues (Tables)	Sep. 30, 2024
Revenue from Contract with Customer [Abstract]
Summary of Revenues by Collaboration, Category of Revenue and Method of Recognition	The following table summarizes our revenues by collaboration, category of revenue, and the method of recognition (in millions): Three Months Ended September 30, Nine Months Ended September 30, Over time Point in time 2024 2023 2024 2023 Gilead Collaboration License and R&D services * $ 25 $ 20 $ 185 $ 57 Access rights * 5 8 22 25 Taiho Collaboration License revenue * 15 — 15 — R&D services * 3 4 10 4 Total revenues $ 48 $ 32 $ 232 $ 86
Summary of Revenue Recognized as a Result of Changes in Deferred Revenue	The following table summarizes the revenue recognized as a result of changes in the deferred revenue balance (in millions): Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Revenue recognized from amounts in deferred revenue at the beginning of the period $ 33 $ 28 $ 212 $ 79
Summary of Transaction Price and Allocation of Transaction Price to the Performance Obligations	The following table summarizes the transaction price (in millions): Transaction price Amount Premium from Third Stock Purchase Agreement Amendment $ 87 Option continuation payment received in the third quarter of 2024 100 Deferred revenue as of January 29, 2024 335 Total transaction price $ 522 The following table summarizes the allocation of the transaction price to the performance obligations (in millions): Allocation to performance obligations Distinct Combined Amount Etrumadenant - License and R&D services * $ 210 Quemliclustat - License and R&D services * 168 Domvanalimab - R&D services * 33 Access rights * 57 Option continuation periods * 20 Rights to certain studies * 34 Total allocated transaction price $ 522 The following table summarizes the allocation of the transaction price to the performance obligations (in millions): Allocation to performance obligations Distinct Amount Inflammation target 1 - R&D services * $ 18 Inflammation target 2 - R&D services * 17 Total allocated transaction price $ 35

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	9 Months Ended
Net Loss Per Share (Tables)	Sep. 30, 2024
Earnings Per Share [Abstract]
Summary of Outstanding Potentially Dilutive Securities Excluded from Computation of Diluted Net Loss Per Share	The following table summarizes potentially dilutive securities excluded from the computation of diluted net loss per share calculations because they would have been antidilutive (in millions): September 30, 2024 September 30, 2023 Common stock options issued and outstanding 15.5 13.7 Restricted stock units issued 3.0 1.9 Employee Stock Purchase Plan shares 0.2 0.2 Total potential dilutive securities 18.7 15.8

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
Stock-Based Compensation (Tables)	Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]
Summary of Stock-Based Compensation Expense	The following table reflects the components of stock-based compensation expense recognized in our Condensed Consolidated Statements of Operations (in millions): Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Research and development $ 9 $ 8 $ 29 $ 26 General and administrative 10 10 30 29 Total stock-based compensation $ 19 $ 18 $ 59 $ 55

Cash, Cash Equivalents and Ma_2

Cash, Cash Equivalents and Marketable Securities (Tables)	9 Months Ended
Cash, Cash Equivalents and Marketable Securities (Tables)	Sep. 30, 2024
Cash, Cash Equivalents and Marketable Securities [Abstract]
Schedule of Amortized Cost, Gross Unrealized Gains and Losses and Fair Value of Our Cash, Cash Equivalents and Marketable Securities Considered as Available for Sale by Type of Securities	The following table summarizes the amortized cost, gross unrealized gains and losses and the fair value of our cash, cash equivalents and marketable securities, all of which are considered available for sale, by type of securities (in millions): Types of securities as of September 30, 2024 Amortized Cost Unrealized Gain Unrealized Loss Fair Value Money market funds $ 134 $ — $ — $ 134 U.S. treasury securities 258 — — 258 Corporate securities and commercial paper 667 1 — 668 U.S. government agency securities 9 — — 9 Certificate of deposit 22 — — 22 Total cash, cash equivalents and marketable securities $ 1,090 $ 1 $ — $ 1,091 Types of securities as of December 31, 2023 Amortized Cost Unrealized Gain Unrealized Loss Fair Value Money market funds $ 85 $ — $ — $ 85 U.S. treasury securities 213 1 (1) 213 Corporate securities and commercial paper 471 — — 471 U.S. government agency securities 90 — — 90 Certificate of deposit 7 — — 7 Total cash, cash equivalents and marketable securities $ 866 $ 1 $ (1) $ 866
Schedule of Fair Values of Our Cash, Cash Equivalents and Marketable Securities by Location in Condensed Consolidated Balance Sheets and Contractual Maturity	The following table summarizes the fair values of our cash, cash equivalents and marketable securities by location in the Condensed Consolidated Balance Sheets and contractual maturity (in millions): Location in Condensed Consolidated Balance Sheets Contractual Maturity September 30, 2024 December 31, 2023 Cash and cash equivalents — $ 201 $ 127 Marketable securities Within one year 888 632 Long-term marketable securities Between one and three years 2 107 Total cash, cash equivalents and marketable securities $ 1,091 $ 866
Reconciliation of Cash, Cash Equivalents and Restricted Cash	The following table provides a reconciliation of cash, cash equivalents, and restricted cash within the Condensed Consolidated Balance Sheets to the total shown in the Condensed Consolidated Statements of Cash Flows (in millions): As of September 30, 2024 2023 Cash and cash equivalents $ 201 $ 184 Restricted cash (included in Other noncurrent assets) 3 3 Total cash, cash equivalents and restricted cash $ 204 $ 187
Schedule of Cash and Cash Equivalents	The following table provides a reconciliation of cash, cash equivalents, and restricted cash within the Condensed Consolidated Balance Sheets to the total shown in the Condensed Consolidated Statements of Cash Flows (in millions): As of September 30, 2024 2023 Cash and cash equivalents $ 201 $ 184 Restricted cash (included in Other noncurrent assets) 3 3 Total cash, cash equivalents and restricted cash $ 204 $ 187

Condensed Consolidated Balanc_4

Condensed Consolidated Balance Sheet Components (Tables)	9 Months Ended
Condensed Consolidated Balance Sheet Components (Tables)	Sep. 30, 2024
Balance Sheet Related Disclosures [Abstract]
Summary of Prepaid and Other Current Assets	Prepaid expenses and other current assets consisted of the following (in millions): September 30, 2024 December 31, 2023 Prepaid expenses and other assets $ 17 $ 30 Accrued interest receivable 5 4 Total prepaid expenses and other current assets $ 22 $ 34
Summary of Other Current Liabilities	Other current liabilities consisted of the following (in millions): September 30, 2024 December 31, 2023 Accrued research and development $ 57 $ 36 Accrued personnel expenses 27 26 Current portion of lease liabilities 11 11 Other 2 3 Total other current liabilities $ 97 $ 76

Long-term Debt (Tables)

Long-term Debt (Tables)	9 Months Ended
Long-term Debt (Tables)	Sep. 30, 2024
Debt Disclosure [Abstract]
Schedule of Long-Term Debt Instruments	The following table summarizes our borrowings (in millions): September 30, 2024 December 31, 2023 Long-term debt, non-current (Contractual maturity 2029) $ 50 $ — Unamortized discounts and issuance costs (3) — Total long-term debt $ 47 $ —
Schedule of Maturities of Long-Term Debt	The aggregate future minimum payments including principal payments and the end of term charge, due under the Hercules Agreement, are as follows (in millions): Maturity Date Amount 2028 $ 15 2029 39 Total payments $ 54

Leases (Tables)

Leases (Tables)	9 Months Ended
Leases (Tables)	Sep. 30, 2024
Leases [Abstract]
Summary of Cash and Non-cash Information Related to Operating Leases	The following table summarizes our cash and non-cash information related to our operating leases (in millions): Nine Months Ended September 30, 2024 2023 Cash paid for amounts included in measurement of lease liabilities $ 12 $ 12 Cash received from tenant improvement allowances $ — $ 8 Recognition of tenant improvement allowance receivable included in Other current liabilities $ — $ 4

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
Fair Value Measurements (Tables)	Sep. 30, 2024
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis	The following tables summarize the types of assets and liabilities measured at fair value on a recurring basis by level within the fair value hierarchy (in millions): Fair value measurement as of September 30, 2024 Level 1 Level 2 Level 3 Total Assets Money market funds $ 134 $ — $ — $ 134 U.S. treasury securities — 258 — 258 Corporate securities and commercial paper — 668 — 668 U.S. government agency obligations — 9 — 9 Certificate of deposit — 22 — 22 Total assets measured at fair value $ 134 $ 957 $ — $ 1,091 Liabilities Liability for sale of future royalties $ — $ — $ 21 $ 21 Total liabilities measured at fair value $ — $ — $ 21 $ 21 Fair value measurement as of December 31, 2023 Level 1 Level 2 Level 3 Total Assets Money market funds $ 85 $ — $ — $ 85 U.S. treasury securities — 213 — 213 Corporate securities and commercial paper — 471 — 471 U.S. government agency obligations — 90 — 90 Certificate of deposit — 7 — 7 Total assets measured at fair value $ 85 $ 781 $ — $ 866 Liabilities Liability for sale of future royalties $ — $ — $ 19 $ 19 Total liabilities measured at fair value $ — $ — $ 19 $ 19
Summary of Changes of Liabilities for Sale of Future Royalties	The liability for sale of future royalties is reported in Other noncurrent liabilities in the Condensed Consolidated Balance Sheets and changes were as follows (in millions): Nine Months Ended September 30, 2024 2023 Beginning balance $ 19 $ 17 Interest accretion 2 2 Ending balance $ 21 $ 19

Organization, Liquidity and C_2

Organization, Liquidity and Capital Resources - Additional Information (Details) $ in Billions	9 Months Ended
	Sep. 30, 2024 USD ($) segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of reportable segments	1
Number of operating segments	1
Cash and investments \| $	$ 1.1

Related Party - Gilead Scienc_2

Related Party - Gilead Sciences, Inc. - Additional Information (Details) $ / shares in Units, shares in Millions, $ in Millions	1 Months Ended				3 Months Ended				9 Months Ended		12 Months Ended
	Jan. 31, 2024 USD ($) shares	Jun. 30, 2023 USD ($) program shares	May 31, 2023 USD ($) program	Jul. 31, 2020 USD ($)	Sep. 30, 2024 USD ($) $ / shares	Mar. 31, 2024 USD ($)	Sep. 30, 2023 USD ($)	Jun. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) $ / shares	Sep. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($) program	Dec. 31, 2020 USD ($)	Dec. 31, 2023 USD ($)
Related Party Transaction [Line Items]
Common stock share value						$ 228	$ 5	$ 20
Contract with customer, liability, revenue recognized					$ 33		28		$ 212	$ 79
Receivable from collaboration partners, current					16				16					$ 38
Other noncurrent assets					$ 75				$ 75					106
Related Party
Related Party Transaction [Line Items]
Percentage of outstanding common stock held					32.90%				32.90%
Receivable from collaboration partners, current					$ 2				$ 2					20
Other noncurrent assets					0				0					$ 6
Related Party \| Research and Development
Related Party Transaction [Line Items]
Reimbursement from related party for shared costs					$ 2		22		$ 32	89
Purchase Agreement \| Related Party
Related Party Transaction [Line Items]
Common stock shares issued (in shares) \| shares	15.2	1
Common stock share value		$ 20
Funds received for stock purchase agreement	$ 320
Purchase price of common stock allocation to performance obligation	$ 87
Percentage of premium purchase price of common stock									20%
Trailing days average closing price									5 days
Weighted average closing price of our common stock on grant date (in dollars per share) \| $ / shares					$ 33.54				$ 33.54
Purchase Agreement \| Related Party \| Maximum
Related Party Transaction [Line Items]
Right to purchase additional outstanding voting common stock percentage					35%				35%
Gilead Collaboration Agreement
Related Party Transaction [Line Items]
Option payment upon completion of certain IND-enabling activities												$ 60
Option payment upon achievement of certain development milestones												150
Gilead Collaboration Agreement \| Related Party
Related Party Transaction [Line Items]
Collaboration term for current and future clinical programs													10 years
Option continuation payment due upon sixth anniversary of agreement													$ 100
Upfront cash payment				$ 175
Option fee per program for all other programs entering clinical development to exercise option												$ 150
Number of research programs \| program												2
Contract with customer, liability, revenue recognized					$ 30		$ 28		$ 207	$ 82
Gilead Collaboration Agreement \| Related Party \| Maximum
Related Party Transaction [Line Items]
Potential regulatory approval milestones payment receivable related to domvanalimab												$ 500
Amended Gilead Collaboration Agreement
Related Party Transaction [Line Items]
Number of exercise option to programs \| program												3
Option payments received											$ 725
Removal of option continuation payment under agreement												$ 100
Option payment upon achievement of certain development milestones			$ 150
Number of programs, eligible to receive regulatory and commercial milestone payments \| program			2
Amended Gilead Collaboration Agreement \| Related Party
Related Party Transaction [Line Items]
Upfront cash payment		$ 35	$ 17.5
Number of research programs \| program		2
Option payment upon completion of certain IND-enabling activities			45
Amended Gilead Collaboration Agreement \| Related Party \| Maximum
Related Party Transaction [Line Items]
Regulatory and commercial milestone payments received			$ 375

License and Collaborations - Ad

License and Collaborations - Additional Information (Details) - USD ($) $ in Millions	1 Months Ended			3 Months Ended			9 Months Ended		12 Months Ended
	Oct. 31, 2024	Jul. 31, 2024	Jan. 31, 2024	Mar. 31, 2025	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2020	Dec. 31, 2017	Dec. 31, 2023
License And Collaboration Agreements [Line Items]
Revenue recognized from amounts in deferred revenue at the beginning of the period					$ 33	$ 28	$ 212	$ 79
Total revenues					48	32	232	86
Receivable from collaboration partners, current					16		16				$ 38
Other noncurrent assets					75		75				106
Other current liabilities					97		97				76
Other noncurrent liabilities					136		136				142
Research and development expense					123	82	347	247
Taiho Collaboration Agreement
License And Collaboration Agreements [Line Items]
Total revenues					3	4	10	4
Receivable from collaboration partners, current					14		14				18
Taiho Collaboration Agreement \| Subsequent Event
License And Collaboration Agreements [Line Items]
Milestone payments	$ 19
AstraZeneca Agreement
License And Collaboration Agreements [Line Items]
Milestone payments									$ 24
Development cost recorded within research and development expenses					4	1	10	6
Other liabilities					22		22
Other current liabilities					10		10
Other noncurrent liabilities					12		12				11
Gilead Collaboration Agreement
License And Collaboration Agreements [Line Items]
Other noncurrent assets											$ 6
Development cost recorded within research and development expenses							6
Exelixis Collaboration
License And Collaboration Agreements [Line Items]
Research and development expense					2	1	5	1
Taiho Pharmaceutical Co., Ltd \| Taiho Agreement
License And Collaboration Agreements [Line Items]
Option period										5 years
Non refundable and non creditable cash payments										$ 35
Payment for option exercise		$ 15			15
Royalties payable term										10 years
Total revenues					18	4	25	4
Reimbursement of research and development expense					3	2	10	4
Taiho Pharmaceutical Co., Ltd \| Taiho Agreement \| Minimum
License And Collaboration Agreements [Line Items]
Payment for option exercise										$ 3
Taiho Pharmaceutical Co., Ltd \| Taiho Agreement \| Maximum
License And Collaboration Agreements [Line Items]
Payment for option exercise										15
Additional clinical and regulatory milestone payments receivable										130
Contingent milestone payments receivable										$ 145
STAR-221 Development Activities \| Taiho Collaboration Agreement
License And Collaboration Agreements [Line Items]
Payment for option exercise							28
STAR-121 Development Activities \| Taiho Collaboration Agreement
License And Collaboration Agreements [Line Items]
Payment for option exercise			$ 26
Revenue recognized from amounts in deferred revenue at the beginning of the period							16
STAR-121 Development Activities \| Taiho Collaboration Agreement \| Forecast
License And Collaboration Agreements [Line Items]
Revenue recognized from amounts in deferred revenue at the beginning of the period				$ 10
WuXi Biologics License Agreement \| anti-CD39 \| Research and Development
License And Collaboration Agreements [Line Items]
Development milestone expense					$ 0	$ 0	0	$ 1
WuXi Biologics License Agreement \| Maximum \| anti-PD-1
License And Collaboration Agreements [Line Items]
Clinical regulatory milestone payments							50
Clinical, regulatory and commercialization milestone payments							375
WuXi Biologics License Agreement \| Maximum \| anti-CD39
License And Collaboration Agreements [Line Items]
Additional clinical, regulatory and commercialization milestone payments							14
Abmuno License Agreement
License And Collaboration Agreements [Line Items]
Additional clinical, regulatory and commercialization milestone payments							$ 88

Revenues - Summary of Revenues

Revenues - Summary of Revenues by Collaboration, Category of Revenue and Method of Recognition (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
License And Collaboration Agreements [Line Items]
Revenue from contract with customer, excluding assessed tax	$ 48	$ 32	$ 232	$ 86
License and R&D services \| Gilead Collaboration \| Over time
License And Collaboration Agreements [Line Items]
Revenue from contract with customer, excluding assessed tax	25	20	185	57
Access rights \| Gilead Collaboration \| Over time
License And Collaboration Agreements [Line Items]
Revenue from contract with customer, excluding assessed tax	5	8	22	25
License revenue \| Taiho Collaboration \| Point in time
License And Collaboration Agreements [Line Items]
Revenue from contract with customer, excluding assessed tax	15	0	15	0
R&D services \| Taiho Collaboration \| Over time
License And Collaboration Agreements [Line Items]
Revenue from contract with customer, excluding assessed tax	$ 3	$ 4	$ 10	$ 4

Revenues - Additional Informati

Revenues - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions		1 Months Ended		3 Months Ended			9 Months Ended
	Jan. 29, 2024	Jul. 31, 2024	Jan. 31, 2024	Mar. 31, 2025	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Jun. 30, 2023
Disaggregation of Revenue [Line Items]
Contract with customer, liability					$ 394		$ 394		$ 398
Contract with customer, liability, cumulative catch-up adjustment to revenue, change in measure of progress and change in estimate of transaction price	$ 107
Contract with customer, liability, cumulative catch-up adjustment to revenue, earnings per share, basic (in dollars per share)							$ 1.19
Contract with customer, liability, cumulative catch-up adjustment to revenue, earnings per share, diluted (in dollars per share)							$ 1.19
Option continuation payment received in the third quarter of 2024	100
Premium from Third Stock Purchase Agreement Amendment	87
Deferred revenue as of January 29, 2024	335
Allocation of transaction price	522
Total revenues					48	$ 32	$ 232	$ 86
Revenue recognized from amounts in deferred revenue at the beginning of the period					33	28	212	79
Capitalized contract cost, amortization							3	1
Cost sharing receivable					3		3		3
R&D Activities for Domvanalimab
Disaggregation of Revenue [Line Items]
Revenue recognized from amounts in deferred revenue at the beginning of the period							25
Access Rights and Option Continuation Periods
Disaggregation of Revenue [Line Items]
Total revenues					5	8	22	25
Taiho Collaboration Agreement
Disaggregation of Revenue [Line Items]
Contract with customer, liability					39		39		23
Total revenues					3	4	10	4
Third Gilead Collaboration Agreement Amendment, Third Stock Purchase Agreement Amendment and the Second Investor Rights Agreement Amendment
Disaggregation of Revenue [Line Items]
Capitalized contract cost, gross	8
Third Stock Purchase Agreement Amendment
Disaggregation of Revenue [Line Items]
Capitalized contract cost, gross					5		5
Initial Gilead Collaboration Agreement and Subsequent Amendments
Disaggregation of Revenue [Line Items]
Capitalized contract cost, gross					3		3
Gilead \| Etrumadenant License and Research and Development Services Agreement
Disaggregation of Revenue [Line Items]
Contract with customer, liability	129				176		176		133
Contract with customer liability revenue recognized excluding opening balance							250
Contract with customer, liability, cumulative catch-up adjustment to revenue, change in measure of progress	14
Total revenues					9	21	36	39
Gilead \| Quemliclustat, License and R&D services
Disaggregation of Revenue [Line Items]
Contract with customer, liability	130				39		39		132
Contract with customer liability revenue recognized excluding opening balance							200
Contract with customer, liability, cumulative catch-up adjustment to revenue, change in measure of progress	88
Total revenues					13	(4)	132	11
Gilead \| R&D Activities for Domvanalimab
Disaggregation of Revenue [Line Items]
Contract with customer, liability					23		23		25
Total revenues					1	1	11	3
Contract with customer, liability, cumulative catch-up adjustment to revenue, change in estimate of transaction price	5
Gilead \| Access Rights and Option Continuation Periods
Disaggregation of Revenue [Line Items]
Contract with customer, liability	51				58		$ 58		54
Current and future programs exclusive access period							10 years
Contingent milestone payments receivable	200				300		$ 300
Option continuation payment receivable upon sixth anniversary of agreement	$ 100
Gilead \| Rights to Certain Studies
Disaggregation of Revenue [Line Items]
Contract with customer, liability					34		34
Gilead \| R&D Activities for Inflammation Programs
Disaggregation of Revenue [Line Items]
Contract with customer, liability					25		25		$ 31
Total revenues					$ 2	$ 2	$ 6	$ 3
Gilead \| Revenue Benchmark \| Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Percentage of revenues					63%	88%	89%	95%
STAR-221 Development Activities \| Taiho Collaboration Agreement
Disaggregation of Revenue [Line Items]
Contract with customer, liability										$ 35
Payment for option exercise							$ 28
STAR-121 Development Activities \| Taiho Collaboration Agreement
Disaggregation of Revenue [Line Items]
Revenue recognized from amounts in deferred revenue at the beginning of the period							16
Payment for option exercise			$ 26
STAR-121 Development Activities \| Taiho Collaboration Agreement \| Forecast
Disaggregation of Revenue [Line Items]
Revenue recognized from amounts in deferred revenue at the beginning of the period				$ 10
Taiho Pharmaceutical Co., Ltd \| Taiho Agreement
Disaggregation of Revenue [Line Items]
Total revenues					$ 18	$ 4	$ 25	$ 4
Payment for option exercise		$ 15			$ 15

Revenues - Summary of Revenue R

Revenues - Summary of Revenue Recognized as a Result of Changes in Deferred Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Revenue from Contract with Customer [Abstract]
Revenue recognized from amounts in deferred revenue at the beginning of the period	$ 33	$ 28	$ 212	$ 79

Revenues - Summary of Transacti

Revenues - Summary of Transaction Price and Allocation of Transaction Price to the Performance Obligations (Details) - USD ($) $ in Millions		9 Months Ended
	Jan. 29, 2024	Sep. 30, 2024
Transaction price
Premium from Third Stock Purchase Agreement Amendment	$ 87
Option continuation payment received in the third quarter of 2024	100
Deferred revenue as of January 29, 2024	335
Total transaction price	522
Allocation to performance obligations
Etrumadenant - License and R&D services	210
Quemliclustat - License and R&D services	168
Domvanalimab - R&D services	33
Access rights	57
Option continuation periods	20
Rights to certain studies	34
Total allocated transaction price	$ 522	$ 35
Inflammation target 1 - R&D services
Allocation to performance obligations
Total allocated transaction price		18
Inflammation target 2 - R&D services
Allocation to performance obligations
Total allocated transaction price		$ 17

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Income Tax Disclosure [Abstract]
Income tax expense	$ 0	$ 2	$ 0	$ 5
Effective tax rate		(2.40%)		(2.20%)

Net Loss Per Share - Summary of

Net Loss Per Share - Summary of Outstanding Potentially Dilutive Securities Excluded from Computation of Diluted Net Loss Per Share (Details) - shares shares in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share (in shares)	18.7	15.8
Common stock options issued and outstanding
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share (in shares)	15.5	13.7
Restricted stock units issued
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share (in shares)	3	1.9
Employee Stock Purchase Plan shares
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share (in shares)	0.2	0.2

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock-Based Compensation Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 19	$ 18	$ 59	$ 55
Research and development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	9	8	29	26
General and administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 10	$ 10	$ 30	$ 29

Cash, Cash Equivalents and Ma_3

Cash, Cash Equivalents and Marketable Securities - Schedule of Amortized Cost, Gross Unrealized Gains and Losses and Fair Value of Our Cash, Cash Equivalents and Marketable Securities Considered as Available for Sale by Type of Securities (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	$ 1,090	$ 866
Unrealized Gain	1	1
Unrealized Loss	0	(1)
Fair Value	1,091	866
Money market funds
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	134	85
Unrealized Gain	0	0
Unrealized Loss	0	0
Fair Value	134	85
U.S. treasury securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	258	213
Unrealized Gain	0	1
Unrealized Loss	0	(1)
Fair Value	258	213
Corporate securities and commercial paper
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	667	471
Unrealized Gain	1	0
Unrealized Loss	0	0
Fair Value	668	471
U.S. government agency securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	9	90
Unrealized Gain	0	0
Unrealized Loss	0	0
Fair Value	9	90
Certificate of deposit
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	22	7
Unrealized Gain	0	0
Unrealized Loss	0	0
Fair Value	$ 22	$ 7

Cash, Cash Equivalents and Ma_4

Cash, Cash Equivalents and Marketable Securities - Schedule of Fair Values of Our Cash, Cash Equivalents and Marketable Securities by Location in Condensed Consolidated Balance Sheets and Contractual Maturity (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Cash, Cash Equivalents and Marketable Securities [Abstract]
Cash and cash equivalents	$ 201	$ 127
Marketable securities	888	632
Long-term marketable securities	2	107
Total cash, cash equivalents and marketable securities	$ 1,091	$ 866

Cash, Cash Equivalents and Ma_5

Cash, Cash Equivalents and Marketable Securities - Additional Information (Details)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024 USD ($) position	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) position	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) position
Cash, Cash Equivalents and Marketable Securities [Abstract]
Number of positions in securities in unrealized loss \| position	21		21		105
Credit related losses \| $	$ 0	$ 0	$ 0	$ 0	$ 0

Cash, Cash Equivalents and Ma_6

Cash, Cash Equivalents and Marketable Securities - Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022
Cash, Cash Equivalents and Marketable Securities [Abstract]
Cash and cash equivalents	$ 201	$ 127	$ 184
Restricted cash (included in Other noncurrent assets)	3		3
Total cash, cash equivalents and restricted cash	$ 204	$ 130	$ 187	$ 209
Restricted Cash, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other noncurrent assets ($— and $6 from a related party)		Other noncurrent assets ($— and $6 from a related party)

Condensed Consolidated Balanc_5

Condensed Consolidated Balance Sheet Components - Summary of Prepaid and Other Current Assets (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Balance Sheet Related Disclosures [Abstract]
Prepaid expenses and other assets	$ 17	$ 30
Accrued interest receivable	5	4
Total prepaid expenses and other current assets	$ 22	$ 34

Condensed Consolidated Balanc_6

Condensed Consolidated Balance Sheet Components - Summary of Other Current Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Balance Sheet Related Disclosures [Abstract]
Accrued research and development	$ 57	$ 36
Accrued personnel expenses	27	26
Current portion of lease liabilities	11	11
Other	2	3
Total other current liabilities	$ 97	$ 76

Long-term Debt - Schedule of Lo

Long-term Debt - Schedule of Long-Term Debt Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Debt Disclosure [Abstract]
Long-term debt, non-current (Contractual maturity 2029)	$ 50	$ 0
Unamortized discounts and issuance costs	(3)	0
Total long-term debt	$ 47	$ 0

Long-term Debt - Narrative (Det

Long-term Debt - Narrative (Details) - USD ($) $ in Millions		3 Months Ended	9 Months Ended
	Aug. 27, 2024	Sep. 30, 2024	Sep. 30, 2024
Debt Instrument [Line Items]
Interest expense, debt		$ 1	$ 1
Debt instrument, interest rate, effective percentage		13.39%	13.39%
Hercules Agreement \| Secured Debt
Debt Instrument [Line Items]
Debt instrument, face amount	$ 250	$ 50	$ 50
Proceeds from issuance of secured debt	50
Debt Instrument, additional committed amount	100
Debt Instrument, minimum increments amount	25
Debt instrument, face amount, contingently available	$ 100
Debt instrument, term, extension period	12 months
Debt instrument, periodic payment, principal, term	13 months
Debt instrument, periodic payment, interest, term	48 months
Debt instrument, interest rate, stated percentage	10.45%
Debt instrument, basis spread on variable rate	1.95%
Debt Instrument, variable interest rate, Type [Extensible Enumeration]	Prime Rate [Member]
Debt instrument, upfront facility fees, amount	$ 1
Debt instrument, term charge, percentage	7.75%
Debt instrument, cash balance requirement, minimum, percentage	50%
Debt instrument, unused borrowing capacity, amount		$ 200	$ 200
Debt instrument, face amount, contingently issuable	$ 100
Hercules Agreement \| Secured Debt \| Prior to First Anniversary of the Funding Date
Debt Instrument [Line Items]
Debt instrument, repayment, percentage	3%
Hercules Agreement \| Secured Debt \| Between the First and Second Anniversary of the Funding Date
Debt Instrument [Line Items]
Debt instrument, repayment, percentage	2%
Hercules Agreement \| Secured Debt \| Thereafter of the Funding Date
Debt Instrument [Line Items]
Debt instrument, repayment, percentage	1%

Long-term Debt - Schedule of Ma

Long-term Debt - Schedule of Maturities of Long-Term Debt (Details) - Hercules Agreement $ in Millions	Sep. 30, 2024 USD ($)
Debt Instrument [Line Items]
2028	$ 15
2029	39
Total payments	$ 54

Leases - Summary of Cash and No

Leases - Summary of Cash and Non-cash Information Related to Operating Leases (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Leases [Abstract]
Cash paid for amounts included in measurement of lease liabilities	$ 12	$ 12
Cash received from tenant improvement allowances	0	8
Recognition of tenant improvement allowance receivable included in Other current liabilities	$ 0	$ 4

Leases - Additional Information

Leases - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Leases [Abstract]
Impairment of long-lived assets	$ 0	$ 20	$ 0	$ 20	$ 0
Deposits for letters of credit	$ 3			$ 3		$ 3

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions			1 Months Ended	3 Months Ended
	Jan. 29, 2024	Jun. 27, 2023	Aug. 31, 2023	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Sep. 30, 2024
Class of Stock [Line Items]
Common stock share value				$ 228	$ 5	$ 20
At-the-Market Facility
Class of Stock [Line Items]
Sale of stock, number of shares issued in transaction (in shares)			0.2
Sale of stock, consideration received on transaction			$ 5
Third Stock Purchase Agreement Amendment
Class of Stock [Line Items]
Contract with customer, asset, before allowance for credit loss							$ 228
Capitalized contract cost, gross							$ 5
Gilead \| Second Stock Purchase Agreement
Class of Stock [Line Items]
Common stock shares issued (in shares)		1
Shares issued, price per share (in dollars per share)		$ 19.26
Common stock share value		$ 20
Gilead \| Third Stock Purchase Agreement Amendment
Class of Stock [Line Items]
Common stock shares issued (in shares)	15.2
Shares issued, price per share (in dollars per share)	$ 21
Common stock share value	$ 320
Premiums earned, net	$ 87

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair Value On Recurring Basis - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	$ 1,091	$ 866
Total liabilities measured at fair value	21	19
Liability for sale of future royalties
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total liabilities measured at fair value	21	19
Money market funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	134	85
U.S. treasury securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	258	213
Corporate securities and commercial paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	668	471
U.S. government agency obligations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	9
U.S. government agency securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value		90
Certificate of deposit
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	22	7
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	134	85
Total liabilities measured at fair value	0	0
Level 1 \| Liability for sale of future royalties
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total liabilities measured at fair value	0	0
Level 1 \| Money market funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	134	85
Level 1 \| U.S. treasury securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	0	0
Level 1 \| Corporate securities and commercial paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	0	0
Level 1 \| U.S. government agency obligations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	0
Level 1 \| U.S. government agency securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value		0
Level 1 \| Certificate of deposit
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	0	0
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	957	781
Total liabilities measured at fair value	0	0
Level 2 \| Liability for sale of future royalties
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total liabilities measured at fair value	0	0
Level 2 \| Money market funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	0	0
Level 2 \| U.S. treasury securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	258	213
Level 2 \| Corporate securities and commercial paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	668	471
Level 2 \| U.S. government agency obligations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	9
Level 2 \| U.S. government agency securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value		90
Level 2 \| Certificate of deposit
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	22	7
Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	0	0
Total liabilities measured at fair value	21	19
Level 3 \| Liability for sale of future royalties
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total liabilities measured at fair value	21	19
Level 3 \| Money market funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	0	0
Level 3 \| U.S. treasury securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	0	0
Level 3 \| Corporate securities and commercial paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	0	0
Level 3 \| U.S. government agency obligations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	0
Level 3 \| U.S. government agency securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value		0
Level 3 \| Certificate of deposit
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	$ 0	$ 0

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - BVF Partners L.P. - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022	Dec. 31, 2021
BVF Agreement
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Non-refundable payments received				$ 15	$ 15
Imputed effective rate of interest on unamortized portion of liability	10.10%	20.60%	20.60%
BVF Agreement \| Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Contingent payments upon achievement of certain clinical and regulatory milestones					73
Gilead Collaboration Agreement \| Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Contingent payments upon achievement of certain clinical and regulatory milestones					$ 160

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Changes of Liabilities for Sale of Future Royalties (Details) - BVF Partners L.P. - BVF Agreement - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 19	$ 17
Interest accretion	2	2
Ending balance	$ 21	$ 19