Net Income (Loss) Per Share - Computation of Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended												9 Months Ended
		Sep. 30, 2021		Jun. 30, 2021	[2]	Mar. 31, 2021	[2]	Sep. 30, 2020		Jun. 30, 2020	[2]	Mar. 31, 2020	[2]	Sep. 30, 2021		Sep. 30, 2020
Numerator:
Net income (loss) – basic		$ 50,781	[1]	$ (79,595)		$ (53,592)		$ (42,851)	[2]	$ (20,157)		$ (15,522)		$ (82,406)	[1]	$ (78,530)	[1]
Decrease in fair value of public and private common stock warrant liabilities		(113,601)						0						(81,898)		0
Net loss – diluted	[1]	$ (62,820)						$ (42,851)						$ (164,304)		$ (78,530)
Denominator:
Weighted average common shares outstanding - basic (in shares)	[1]	395,053,445						298,713,456						379,450,553		288,958,713
Incremental common shares from assumed exercise of private warrants (in shares)		976,686						0						6,001,253		0
Weighted average common shares outstanding - diluted (in shares)	[1]	396,030,131						298,713,456						385,451,806		288,958,713
Net income (loss) per share attributable to common stockholders - basic (in dollars per share)	[1]	$ 0.13						$ (0.14)						$ (0.22)		$ (0.27)
Net loss per share attributable to common stockholders - diluted (in dollars per share)	[1]	$ (0.16)						$ (0.14)						$ (0.43)		$ (0.27)

[1] Retroactively restated for the reverse recapitalization as described in Notes 1 and 3.

[2] Retroactively restated for the reverse recapitalization as described in Notes 1 and 3.