Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Statement of Comprehensive Income [Abstract]
Revenue	[1]	$ 61	$ 130	$ 84,683
Operating expenses:
Research and development		171,603	182,945	159,188
General and administrative		52,041	66,983	117,307
Other operating income, net		(3,309)	(2,790)	(4,754)
Acquired in-process research and development		87,184	0	0
Impairment of long-lived assets		51,297	0	0
Total operating expenses		358,816	247,138	271,741
Loss from operations		(358,755)	(247,008)	(187,058)
Interest income, net		24,068	23,453	7,053
Other income, net		4,694	1,846	1,887
Impairment of other investments		(13,001)	(12,923)	(5,000)
Total other income, net		15,761	12,376	3,940
Net loss		(342,994)	(234,632)	(183,118)
Other comprehensive loss:
Net unrealized gain (loss) on marketable securities		385	7,505	(5,976)
Comprehensive loss		$ (342,609)	$ (227,127)	$ (189,094)
Net loss per common share, basic (in dollars per share)		$ (1.31)	$ (0.93)	$ (0.74)
Net loss per common share, diluted (in dollars per share)		$ (1.31)	$ (0.93)	$ (0.74)
Weighted-average shares used to compute net loss per common share, basic (in shares)		261,480	250,983	247,080
Weighted-average shares used to compute net loss per common share, diluted (in shares)		261,480	250,983	247,080

[1] Includes related-party revenue of zero for both the years ended December 31, 2024 and 2023 and $84,653 for the year ended December 31, 2022.