STOCK OPTIONS - SUMMARY OF OPTION ACTIVITY - (Details) - Stock Options - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Summary of option activity - Shares
Outstanding at the beginning of year (in shares)	3,253,310
Granted (in shares)	333,250
Forfeited (in shares)	(257,570)
Exercised (in shares)	(135,205)
Outstanding at the end of period (in shares)	3,193,785	3,253,310
Vested at the end of period (in shares)	1,811,996
Vested and expected to vest at the end of period (in shares)	2,741,045
Summary of option activity - Weighted Average Exercise Price
Outstanding at the beginning of year (in dollars per shares)	$ 7.47
Granted (in dollars per shares)	6.27
Forfeited (in dollars per shares)	8.47
Exercised (in dollars per shares)	1.41
Outstanding at the end of period (in dollars per shares)	7.52	$ 7.47
Vested at the end of period (in dollars per share)	7.54
Vested and expected to vest at the end of period (in dollars per share)	$ 7.52
Option activity disclosures
Weighted Average Remaining Contractual Term - Outstanding	6 years 11 months 5 days
Weighted Average Remaining Contractual Term - Vested	6 years 3 months 26 days
Weighted Average Remaining Contractual Term - Vested and expected to vest	6 years 9 months 22 days
Aggregate Intrinsic Value - Outstanding (in dollars)	$ 571
Aggregate Intrinsic Value - Vested (in dollars)	563
Aggregate Intrinsic Value - Vested and expected to vest (in dollars)	$ 568
Stock Option
Weighted average grant-date fair value of options granted	$ 5.23	$ 7.37	$ 6.15
Total fair value of options vested	$ 5,179	$ 5,144	$ 2,329
Total unrecognized compensation expense, related to non-vested share-based compensation arrangements	$ 5,630
Period for unrecognized compensation expense is estimated to be recognized	2 years 4 months 13 days