Revenues - Summary of Revenues by Collaboration, Category of Revenue and Method of Recognition (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025
License And Collaboration Agreements [Line Items]
Total revenues	$ 17	$ 28
Total revenues from collaborations	10	20
Total revenues from a customer	7	8
License and development services
License And Collaboration Agreements [Line Items]
Total revenues	12	20
License and development services \| Gilead Collaboration \| Over time
License And Collaboration Agreements [Line Items]
Total revenues	8	20
License and development services \| Taiho Collaboration \| Over time
License And Collaboration Agreements [Line Items]
Total revenues	2
R&D services \| Gilead Collaboration \| Over time
License And Collaboration Agreements [Line Items]
Total revenues	2	2
Access rights \| Gilead Collaboration \| Over time
License And Collaboration Agreements [Line Items]
Total revenues	3	6
Other \| Gilead Collaboration \| Over time
License And Collaboration Agreements [Line Items]
Total revenues	$ 2	0
License \| Taiho Collaboration \| Over time
License And Collaboration Agreements [Line Items]
Total revenues		$ 0

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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