Research and Development Funding Expense - R&D Funding Arrangements (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Mar. 31, 2026
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total Commitments	$ 825,000		$ 825,000
Unfunded Commitments	502,649		502,649
Research and development funding expense	97,851	$ 300,500	137,641	$ 351,000
Johnson & Johnson \| JNJ‑4804
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total Commitments	500,000		500,000
Unfunded Commitments	437,500		437,500
Teva Pharmaceuticals \| TEV-408
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total Commitments	75,000		75,000
Unfunded Commitments	65,149		65,149
Research and development commitment					$ 500,000
Teva Pharmaceuticals \| Phase 2b, TEV-408
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and development commitment					75,000
R&D funding expense, accrued portion	14,300		14,300
Teva Pharmaceuticals \| Phase 3, TEV-408
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and development commitment					$ 425,000
Biogen \| Litifilimab
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total Commitments	250,000		250,000
Unfunded Commitments	$ 0		$ 0