Net Loss per Share - Summary of Basic and Diluted Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Numerator:
Net loss	$ (299,964)	$ (266,489)	$ (192,256)
Denominator:
Weighted average common shares outstanding—basic and diluted (in shares)	58,084,325	55,780,982	42,869,058
Net loss per share—basic and diluted (in dollars per share)	$ (5.16)	$ (4.78)	$ (4.48)