Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Revenue — related party		$ 41,817	$ 57,052
Operating expenses:
Research and development		(66,193)	(47,353)
General and administrative		(17,269)	(10,930)
Total operating expenses		(83,462)	(58,283)
Loss from operations		(41,645)	(1,231)
Interest income		478	816
Other expense, net		(366)	(216)
Net loss		(41,533)	(631)
Accretion to redemption value and dividends on redeemable convertible preferred stock		0	(6,225)
Net loss attributable to common stockholders		$ (41,533)	$ (6,856)
Net loss per share, attributable to common stockholders:
Basic		$ (1.95)	$ (4.22)
Diluted		$ (1.95)	$ (4.22)
Shares used in computing net loss per share attributable to common stockholders:
Basic		21,344,236	1,623,358
Diluted		21,344,236	1,623,358
Comprehensive loss:
Net loss		$ (41,533)	$ (631)
Other comprehensive loss:
Net unrealized loss on short-term investments	[1]	(31)	(1)
Total other comprehensive loss		(31)	(1)
Comprehensive loss		$ (41,564)	$ (632)

[1] Tax effect is nil for all periods presented.