STOCK-BASED COMPENSATION - Schedule of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Options
Outstanding, beginning balance (in shares)	3,752,744
Granted (in shares)	1,996,644
Exercised (in shares)	(110,621)
Canceled or forfeited (in shares)	(734,928)
Outstanding, ending balance (in shares)	4,903,839	3,752,744
Options vested or expected to vest (in shares)	4,903,839
Options exercisable (in shares)	1,791,964
Weighted Average Exercise Price
Outstanding, beginning balance (in dollars per share)	$ 15.71
Granted (in dollars per share)	21.61
Exercised (in dollars per share)	6.02
Cancelled or forfeited (in dollars per share)	22.24
Outstanding, ending balance (in dollars per share)	17.38	$ 15.71
Options vested or expected to vest (in dollars per share)	17.38
Options exercisable (in dollars per share)	$ 14.27
Weighted Average Remaining Life and Intrinsic Value
Options outstanding, remaining life	7 years 7 months 6 days	9 years
Options vested or expected to vest, remaining life	7 years 7 months 6 days
Options exercisable, remaining life	6 years 4 months 24 days
Options outstanding, intrinsic value	$ 847	$ 62,842
Options vested or expected to vest, intrinsic value	847
Options exercisable, intrinsic value	$ 583