Stockholders’ Equity - Option Activity (Details) - Employee, excluding CEO - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Shares
Beginning balance (in shares)	10,401
Granted (in shares)	5,585
Exercised (including early exercised options vested during the period) (in shares)	(793)
Forfeited and expired (in shares)	(334)
Ending balance (in shares)	14,859	10,401
Exercisable at the end of the period (in shares)	8,066
Weighted Average Exercise Price
Beginning balance (in dollars per share)	$ 4.01
Granted (in dollars per share)	5.01
Exercised (including early exercised options vested during the period) (in dollars per share)	1.20
Forfeited and expired (in dollars per share)	5.58
Ending balance (in dollars per share)	4.51	$ 4.01
Exercisable at the end of the period (in dollars per share)	$ 3.10
Weighted Average Contractual Period (in Years)
Outstanding balance (in years)	8 years 6 months 18 days	7 years 8 months 23 days
Exercisable at the end of the period (in years)	7 years 6 months 7 days
Aggregate Intrinsic Value
Outstanding balance	$ 26,306	$ 37,868
Exercisable at the end of the period	$ 24,213