Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Total revenue	$ 133,617	$ 207,085	$ 21,098
Type of Revenue [Extensible List]	Collaboration Revenue [Member]	Collaboration Revenue [Member]	Collaboration Revenue [Member]
Operating expenses:
Research and development	$ 210,418	$ 189,407	$ 156,869
General and administrative	61,033	55,038	59,403
Total operating expenses	271,451	244,445	216,272
Loss from operations	(137,834)	(37,360)	(195,174)
Other income, net	7,778	1,031	4,946
Loss before income taxes	(130,056)	(36,329)	(190,228)
Income tax expense	3,254	0	0
Net loss	(133,310)	(36,329)	(190,228)
Unrealized gain (loss) on marketable securities	(3,632)	(1,557)	472
Comprehensive loss	$ (136,942)	$ (37,886)	$ (189,756)
Net loss per share, basic	$ (1.62)	$ (0.45)	$ (2.45)
Net loss per share, diluted	$ (1.62)	$ (0.45)	$ (2.45)
Shares used in computing net loss per share, basic	82,467,587	80,416,936	77,758,806
Shares used in computing net loss per share, diluted	82,467,587	80,416,936	77,758,806