Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Comprehensive Income [Abstract]
Revenues	[1]	$ 84,683	$ 10,650	$ 7,756
Operating expenses:
Research and development		159,188	138,693	182,243
General and administrative		117,307	89,057	46,881
Other operating income, net		(4,754)	(2,324)	(9,431)
Total operating expenses		271,741	225,426	219,693
Loss from operations		(187,058)	(214,776)	(211,937)
Interest income, net		7,053	1,165	5,939
Other income (expense), net		1,887	(161)	1,526
Impairment of other investments		(5,000)	(36,447)	0
Total other income (loss), net		3,940	(35,443)	7,465
Net loss		(183,118)	(250,219)	(204,472)
Other comprehensive loss:
Net unrealized loss on marketable securities		(5,976)	(1,879)	(198)
Comprehensive loss		(189,094)	(252,098)	(204,670)
Net loss attributed to common stockholders:
Net loss		(183,118)	(250,219)	(204,472)
Deemed dividends upon repurchase of convertible preferred stock		0	0	(3,582)
Net loss attributed to common stockholders		$ (183,118)	$ (250,219)	$ (208,054)
Net loss per common share, basic (in dollars per share)		$ (0.74)	$ (1.84)	$ (15.69)
Net loss per common share, diluted (in dollars per share)		$ (0.74)	$ (1.84)	$ (15.69)
Weighted-average shares used to compute net loss per common share, basic (in shares)		247,080	135,918	13,258
Weighted-average shares used to compute net loss per common share, diluted (in shares)		247,080	135,918	13,258

[1] Includes related-party revenue of $84,653, $10,509 and $7,756 for the years ended December 31, 2022, 2021 and 2020, respectively.