Net Loss per Share Attributable to Common Stockholders - Summary of Computation of Basic and Diluted Net Loss per Share Attributable to Common Stockholders (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Numerator:
Net loss	$ (194,592)	$ (78,326)
Accretion of redeemable convertible preferred stock to redemption value, including dividends on preferred stock	(1,277)	(12,714)
Net loss attributable to common stockholders	$ (195,869)	$ (91,040)
Denominator:
Weighted average number of common shares, basic and diluted	46,733,221	6,479,591
Net loss per common share attributable to common stockholders, basic and diluted	$ (4.19)	$ (14.05)