STOCK BASED COMPENSATION - Restricted Stock Units (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Weighted Average Remaining Contractual Life
Restricted stock units	2 years 3 months 29 days
Aggregate Intrinsic Value
Restricted stock units	$ 1,158
Restricted Stock Units
Restricted Stock Units
Vesting period	5 years
Restricted Stock Units
Restricted stock units at the beginning of the period (in shares)	161,000	80,000
Awarded (in shares)	10,000	81,000
Released (in shares)	0	0
Forfeited (in shares)	(6,000)
Restricted stock units at the end of the period (in shares)	165,000	161,000	80,000
Weighted-Average Grant Date Fair Value
Restricted stock units at the beginning of the period (in dollars per share)	$ 3.16	$ 1.00
Awarded (in dollars per share)	11.20	5.29
Forfeited (in dollars per share)	6.00
Restricted stock units at the end of the period (in dollars per share)	3.54	$ 3.16	$ 1.00
Weighted Average Remaining Contractual Life
Restricted stock units		3 years 3 months 18 days	3 years 7 months 6 days
Aggregate Intrinsic Value
Restricted stock units		$ 921	$ 528
Stock price	$ 7.02	$ 5.71
Vested (in shares)	0	0
Restricted Stock Units | First installment
Restricted Stock Units
Vesting (as a percent)	50.00%
Restricted Stock Units | Second installment
Restricted Stock Units
Vesting (as a percent)	50.00%