SHARE-BASED COMPENSATION - Stock option activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2020	Dec. 31, 2021
Options
Outstanding at beginning of period (in shares)			6,687,128
Granted (in shares)	425,000	209,000	425,000
Exercised (in shares)			(16,000)
Forfeited, shares (in shares)			(160,167)
Outstanding at end of period (in shares)	6,935,961		6,935,961		6,687,128
Exercisable at end of period (in shares)	4,350,315		4,350,315
Weighted average exercise price
Outstanding at beginning of period (in dollars per share)			$ 22.43
Granted (in dollars per share)			9.51
Exercised (in dollars per share)			2.00
Forfeited (in dollars per share)			31.03
Outstanding at end of period (in dollars per share)	$ 21.48		21.48		$ 22.43
Exercisable at end of period (in dollars per share)	$ 18.19		$ 18.19
Aggregate intrinsic value and Weighted average remaining contractual life (years)
Outstanding (in dollars)	$ 25,565		$ 25,565		$ 26,412
Exercisable (in dollars)	$ 23,232		$ 23,232
Outstanding (in years)			6 years 10 months 13 days		7 years 2 months 15 days
Exercisable (in years)			5 years 8 months 8 days
Weighted average grant-date fair value of stock options granted (in dollars per share)	$ 6.28	$ 32.44	$ 6.28	$ 32.44
Senior executives and certain other employees under retention program
Options
Granted (in shares)	255,000
Employees not included under retention program
Options
Granted (in shares)	170,000