Condensed Statements of Operations and Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Income Statement [Abstract]
Revenue	$ 1,249	$ 2,174
Operating expenses:
Research and development	(20,881)	(18,527)
General and administrative	(8,579)	(6,566)
Total operating expenses	(29,460)	(25,093)
Loss from operations	(28,211)	(22,919)
Interest and other income (expense), net	111	63
Net loss	$ (28,100)	$ (22,856)
Net loss per share:
Basic (USD per share)	$ (0.78)	$ (0.64)
Diluted (USD per share)	$ (0.78)	$ (0.64)
Shares used in computing net loss per share:
Basic (in shares)	36,116,440	35,645,205
Diluted (in shares)	36,116,440	35,645,205
Comprehensive loss:
Net loss	$ (28,100)	$ (22,856)
Net unrealized (loss) gain on short-term investments	(749)	14
Total other comprehensive (loss) income	(749)	14
Comprehensive loss	$ (28,849)	$ (22,842)