Segment Reporting - Schedule of Segment Reporting Information, by Segment (Details) - USD ($) $ in Thousands		12 Months Ended
	Sep. 09, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Segment revenue		$ 74,205	$ 86,180	$ 1,615,797
Less: Segment expenses
Cost of sales		845	2,765	146,319
Research and development
Selling, general and administrative		119,031	174,441	161,762
Restructuring, long-lived assets impairment and related charges		34,995	13,559	0
Net (loss) income		(521,960)	(615,117)	515,837
Sanofi Agreement
Research and development
IPR&D	$ 102,836	102,800
Reportable Segment
Segment Reporting Information [Line Items]
Segment revenue		74,205	86,180	1,615,797
Less: Segment expenses
Cost of sales		845	2,765	146,319
Research and development
Contract manufacturing		40,081	114,262	47,960
Clinical costs		57,624	121,422	118,849
Personnel		162,960	189,418	157,167
Licenses, collaborations and contingent consideration		129,846	30,215	54,087
Other R&D		115,988	124,403	96,585
Selling, general and administrative		119,031	174,441	161,762
Restructuring, long-lived assets impairment and related charges		34,995	13,559	0
Plus: Other segment items		65,205	69,188	(317,231)
Net (loss) income		$ (521,960)	$ (615,117)	$ 515,837