CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenues:
Total revenues	$ 1,173	$ 2,713	$ 9,068	$ 5,762
Operating expenses:
Cost of revenue	0	0	1,000	141
Research and development	23,695	12,240	70,172	46,948
General and administrative	19,714	7,634	56,969	21,810
Total operating expenses	43,409	19,874	128,141	68,899
Loss from operations	(42,236)	(17,161)	(119,073)	(63,137)
Interest expense	(1,216)	(1,202)	(3,518)	(3,785)
Other (expense) income, net	(134)	255	664	1,485
Loss before provision for income taxes	(43,586)	(18,108)	(121,927)	(65,437)
Provision for income taxes	1	0	4	0
Net loss	$ (43,587)	$ (18,108)	$ (121,931)	$ (65,437)
Net loss per share - basic (in dollars per share)	$ (0.42)	$ (0.20)	$ (1.21)	$ (0.73)
Net loss per share - diluted (in dollars per share)	$ (0.42)	$ (0.20)	$ (1.21)	$ (0.73)
Shares used in computing net loss per share - basic	104,144,606	89,365,798	100,480,156	89,109,772
Shares used in computing net loss per share - diluted	104,144,606	89,365,798	100,480,156	89,109,772
Comprehensive loss:
Net loss	$ (43,587)	$ (18,108)	$ (121,931)	$ (65,437)
Unrealized (losses) gains on available-for-sale securities	(1)	(227)	7	70
Comprehensive loss	(43,588)	(18,335)	(121,924)	(65,367)
Collaborative development revenue
Revenues:
Total revenues	886	1,356	3,650	3,656
Product supply revenue
Revenues:
Total revenues	285	1,357	411	1,400
Licensing revenue
Revenues:
Total revenues	$ 2	$ 0	$ 5,007	$ 706