Segment reporting - Summary of Segment Loss Including Segment Expenses (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting [Abstract]
Research and laboratory		$ 51,133	$ 85,197	$ 105,482
Technical operations and manufacturing		39,713	52,359	55,621
Clinical development		35,389	27,370	22,093
Facility costs		49,429	54,778	49,186
Support functions		45,587	54,355	51,390
Stock-based compensation		37,678	35,533	36,397
Portfolio prioritization costs		5,840	5,203	8,704
Other	[1]	16,835	27,327	28,573
Research and development related success payments and contingent consideration		(8,881)	(48,981)	(84,882)
Total operating expenses		272,723	293,141	272,564
Loss from operations		(272,723)	(293,141)	(272,564)
Interest income, net		10,471	9,938	3,762
Other expense, net		(4,507)	(52)	(674)
Net loss		$ (266,759)	$ (283,255)	$ (269,476)
Segment reporting, other segment item, composition, description		Other segment expenses includes licensing costs, consulting fees, business taxes, insurance costs, impairment of certain lab equipment and leasehold improvements for the years ended December 31, 2024 and 2023, and costs incurred for the early termination of the Fremont lease for the year ended December 31, 2023.

[1] (1) Other segment expenses includes licensing costs, consulting fees, business taxes, insurance costs, impairment of certain lab equipment and leasehold improvements for the years ended December 31, 2024 and 2023, and costs incurred for the early termination of the Fremont lease for the year ended December 31, 2023.