STOCK-BASED COMPENSATION - SUMMARY OF TIME-BASED STOCK OPTIONS (Details) - Time-based stock options - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Number of Shares Underlying Stock Options
Beginning outstanding balance (in shares)	967
Granted (in shares)	456
Canceled or expired (in shares)	(53)
Ending outstanding balance (in shares)	1,370	967
Number of shares underlying stock options, Vested and expected to vest (in shares)	1,178
Number of shares underlying stock options, Exercisable (in shares)	344
Weighted Average Exercise Price Per Share
Beginning outstanding balance (in dollars per share)	$ 8.55
Granted (in dollars per share)	7.58
Canceled or expired (in dollars per share)	9.73
Ending outstanding balance (in dollars per share)	8.18	$ 8.55
Weighted average exercise price, Vested and expected to vest (in dollars per share)	8.23
Weighted average exercise price, Exercisable (in dollars per share)	$ 8.89
Weighted average remaining contractual life, Outstanding	5 years 10 months 2 days	5 years 7 months 17 days
Weighted average remaining contractual life, Vested and expected to vest	5 years 9 months 10 days
Weighted average remaining contractual life, Exercisable	4 years 9 months 3 days
Aggregate intrinsic value, Outstanding	$ 0	$ 16
Aggregate intrinsic value, Vested and expected to vest	0
Aggregate intrinsic value, Exercisable	$ 0