Net Loss per Share - Schedule of basic and diluted net loss per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Numerator:
Net loss attributable to common stockholders ($ in thousands)	$ (26,757)	$ (10,630)	$ (171,644)	$ (36,417)
Denominator:
Weighted average common shares outstanding — basic (in shares)	127,166,524	8,888,099	109,988,189	8,882,040
Weighted average common shares outstanding - diluted (in shares)	127,166,524	8,888,099	109,988,189	8,882,040
Net loss per share attributable to common stockholders — basic (in dollars per share)	$ (0.21)	$ (1.20)	$ (1.56)	$ (4.10)
Net loss per share attributable to common stockholders - diluted (in dollars per share)	$ (0.21)	$ (1.20)	$ (1.56)	$ (4.10)