Research and Development Funding Expense	6 Months Ended
Jun. 30, 2025
Research and Development [Abstract]
Research and Development Funding Expense	Research and Development Funding Expense R&D funding expense consists of development-stage funding payments that we have made to counterparties to acquire royalties or milestones on product candidates. The payments can be made upfront, as milestones upon the achievement of certain predefined criteria, or over time as the related product candidates undergo clinical trials. In the first quarter of 2025, we entered into an R&D funding arrangement with Biogen to provide $250 million over six quarters, including $50 million upfront for the development of litifilimab. We did not enter into ongoing R&D funding arrangements in 2024. We recognized R&D funding expense of $300.5 million and $351.0 million in the second quarter and first six months of 2025, respectively, primarily related to an upfront payment of $250.0 million to acquire royalties on daraxonrasib and the R&D funding arrangement for litifilimab. We recognized R&D funding expense of $0.5 million and $1.0 million in the second quarter and first six months of 2024, respectively, related to ongoing development-stage funding payments. As of June 30, 2025, we had an unfunded commitment of $150 million related to the R&D funding arrangement with Biogen for litifilimab.

R&D funding expense consists of development-stage funding payments that we have made to counterparties to acquire royalties or milestones on product candidates. The payments can be made upfront, as milestones upon the achievement of certain predefined criteria, or over time as the related product candidates undergo clinical trials. In the first quarter of 2025, we entered into an R&D funding arrangement with Biogen to provide $250 million over six quarters, including $50 million upfront for the development of litifilimab. We did not enter into ongoing R&D funding arrangements in 2024.

We recognized R&D funding expense of $300.5 million and $351.0 million in the second quarter and first six months of 2025, respectively, primarily related to an upfront payment of $250.0 million to acquire royalties on daraxonrasib and the R&D funding arrangement for litifilimab. We recognized R&D funding expense of $0.5 million and $1.0 million in the second quarter and first six months of 2024, respectively, related to ongoing development-stage funding payments.

As of June 30, 2025, we had an unfunded commitment of $150 million related to the R&D funding arrangement with Biogen for litifilimab.