NET LOSS PER SHARE - Potentially dilutive securities (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	16,863,218	23,851,390
Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	8,193,012	4,252,258
Convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	8,670,206	19,599,132