Unaudited Condensed Consolidated Statements of Changes in Redeemable Convertible Preferred Stock and Stockholders' Deficit - USD ($) $ in Thousands	Total	Series D	Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2020			76,494,000	24,696,000
Beginning balance at Dec. 31, 2020	$ (138,902)		$ 182,599	$ 1	$ 13,233	$ 0	$ (152,136)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Series D preferred stock (in shares)		2,256,000
Issuance of Series D preferred stock		$ 13,721
Issuance of Series D preferred stock - related party		2,466,000
Issuance of Series D preferred stock - related party		$ 15,000
Issuance Costs - Series D		$ (1,290)
Issuance of restricted stock awards - related party (in shares)				6,917,000
Issuance of restricted stock awards - related party	$ 40,237			$ 1	40,236
Issuance of Common Stock upon exercise of options (in shares)	12,796,353			619,000
Issuance of Common Stock upon exercise of options	$ 864			$ 1	863
Stock-based compensation expense - options	5,283				5,283
Other comprehensive gain/loss	0
Net loss	(65,171)						(65,171)
Ending balance (in shares) at Mar. 31, 2021			81,216,000	32,232,000
Ending balance at Mar. 31, 2021	(157,689)		$ 210,030	$ 3	59,615	0	(217,307)
Beginning balance (in shares) at Dec. 31, 2020			76,494,000	24,696,000
Beginning balance at Dec. 31, 2020	$ (138,902)		$ 182,599	$ 1	13,233	0	(152,136)
Ending balance (in shares) at Dec. 31, 2021	162,105,399		0	162,105,000
Ending balance at Dec. 31, 2021	$ 282,136		$ 0	$ 16	710,638	213	(428,731)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Common Stock upon exercise of options (in shares)	139,423			139,000
Issuance of Common Stock upon exercise of options	$ 144				144
Stock-based compensation expense - options	16,485				16,485
Other comprehensive gain/loss	88					88
Net loss	$ (48,149)						(48,149)
Ending balance (in shares) at Mar. 31, 2022	162,244,822		0	162,244,000
Ending balance at Mar. 31, 2022	$ 250,704		$ 0	$ 16	$ 727,267	$ 301	$ (476,880)