Net Loss Per Share - Schedule of Computation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ 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
Numerator:
Net loss	$ (18,554)	$ (18,370)	$ (13,723)	$ (11,785)	$ (8,040)	$ (7,849)	$ (50,647)	$ (27,674)
Cumulative dividends on redeemable convertible preferred stock				(2,185)			(1,228)	(3,755)
Net loss attributable to common stockholders	$ (18,554)			$ (13,970)			$ (51,875)	$ (31,429)
Denominator:
Weighted-average number of common shares outstanding, basic and diluted	36,934,311			228,144			32,067,535	176,726
Net loss per share attributable to common stockholders, basic and diluted	$ (0.50)			$ (61.23)			$ (1.62)	$ (177.84)