Net Loss per Common Share - Schedule of Computation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Net loss	$ (30,696)	$ (42,571)	$ (37,215)	$ (18,817)	$ (7,743)	$ (5,149)	$ (110,482)	$ (31,709)
Weighted-average shares outstanding	44,797			4,465			43,722	4,465
Less: weighted-average unvested restricted shares and shares subject to repurchase	(136)			(280)			(159)	(318)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted	44,661			4,185			43,563	4,147
Net loss per share attributable to common stockholders, basic and diluted	$ (0.69)			$ (4.50)			$ (2.54)	$ (7.65)