STOCK-BASED AWARDS - Schedule of Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Number of Options
Balance - beginning of period (in shares)	64,119,902
Options granted (in shares)	0
Options exercised (in shares)	(12,103,110)
Options canceled (in shares)	(1,316,554)
Balance - end of period (in shares)	50,700,238	64,119,902
Weighted Average Exercise Price
Balance - beginning of period (in dollars per share)	$ 1.14	$ 1.08
Options granted (in dollars per share)	0
Options exercised (in dollars per share)	0.76
Options canceled (in dollars per share)	1.60
Balance - end of period (in dollars per share)	$ 1.14	$ 1.08
Additional Disclosures
Options outstanding, weighted average remaining contractual term	7 years 3 days	6 years 7 months 6 days
Options outstanding, intrinsic value	$ 1,231,047	$ 2,370,666
Options vested and exercisable, number of options (in shares)	33,233,881
Options vested and exercisable, weighted average exercise price (in dollars per share)	$ 0.90
Options vested and exercisable, weighted average remaining contractual term	6 years 3 months 25 days
Options vested and exercisable, intrinsic value	$ 814,996