STOCK-BASED COMPENSATION - SUMMARY OF STOCK OPTIONS (Details)	6 Months Ended
	Jun. 30, 2018 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, beginning of period (in shares) | shares	4,860,157
Granted (in shares) | shares	117,000
Exercised (in shares) | shares	(37,250)
Canceled and forfeited (in shares) | shares	(57,500)
Outstanding, end of period (in shares) | shares	4,882,407
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Outstanding, beginning of period (in dollars per share) | $ / shares	$ 3.00
Granted (in dollars per share) | $ / shares	2.95
Exercised (in dollars per share) | $ / shares	2.23
Canceled and forfeited (in dollars per shares) | $ / shares	6.55
Outstanding, end of period (in dollars per share) | $ / shares	$ 2.94