Basic and Diluted Net Loss per Share - 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 attributable to common stockholders	$ (15,941)	$ (9,153)	$ (51,404)	$ (5,871)	$ (981)	$ (6,033)	$ (76,498)	$ (12,885)
Denominator:
Weighted average shares outstanding, basic (in shares)	200,038,761			35,614,598			181,867,522	35,345,972
Weighted average shares outstanding, diluted (in shares)	200,038,761			35,614,598			181,867,522	35,345,972
Basic net loss per share (in dollars per share)	$ (0.08)			$ (0.16)			$ (0.42)	$ (0.36)
Diluted net loss per share (in dollars per share)	$ (0.08)			$ (0.16)			$ (0.42)	$ (0.36)
Common Class A
Numerator:
Net loss attributable to common stockholders	$ (15,273)			$ (4,727)			$ (73,219)	$ (10,355)
Denominator:
Weighted average shares outstanding, basic (in shares)	191,661,138			28,673,246			174,072,957	28,404,620
Weighted average shares outstanding, diluted (in shares)	191,661,138			28,673,246			174,072,957	28,404,620
Basic net loss per share (in dollars per share)	$ (0.08)			$ (0.16)			$ (0.42)	$ (0.36)
Diluted net loss per share (in dollars per share)	$ (0.08)			$ (0.16)			$ (0.42)	$ (0.36)
Common Class V
Numerator:
Net loss attributable to common stockholders	$ (668)						$ (3,279)
Denominator:
Weighted average shares outstanding, basic (in shares)	8,377,623						7,794,565
Weighted average shares outstanding, diluted (in shares)	8,377,623						7,794,565
Basic net loss per share (in dollars per share)	$ (0.08)						$ (0.42)
Diluted net loss per share (in dollars per share)	$ (0.08)						$ (0.42)
Common Class F
Numerator:
Net loss attributable to common stockholders				$ (1,144)				$ (2,530)
Denominator:
Weighted average shares outstanding, basic (in shares)				6,941,352				6,941,352
Weighted average shares outstanding, diluted (in shares)				6,941,352				6,941,352
Basic net loss per share (in dollars per share)				$ (0.16)				$ (0.36)
Diluted net loss per share (in dollars per share)				$ (0.16)				$ (0.36)