STOCK BASED COMPENSATION - Restricted Stock Units (Details) - Restricted Stock Units - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Restricted Stock Units
Vesting period	5 years
Restricted Stock Units
Restricted stock units at the beginning of the period (in shares)	161
Awarded (in shares)	10
Released (in shares)	0
Forfeited (in shares)	(6)
Restricted stock units at the end of the period (in shares)	165	161
Weighted-Average Grant Date Fair Value
Restricted stock units at the beginning of the period (in dollars per share)	$ 3.16
Awarded (in dollars per share)	11.20
Forfeited (in dollars per share)	6.00
Restricted stock units at the end of the period (in dollars per share)	$ 3.54	$ 3.16
Weighted Average Remaining Contractual Life
Restricted stock units	2 years 7 months 2 days	3 years 3 months 18 days
Aggregate Intrinsic Value
Restricted stock units	$ 1,650	$ 921
Stock price	$ 10.00	$ 5.71
First installment
Restricted Stock Units
Vesting (as a percent)	50.00%
Second installment
Restricted Stock Units
Vesting (as a percent)	50.00%