STOCK BASED COMPENSATION - Non-vested Options Outstanding and Exercisable (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares
Stock options granted (in shares)	375	338	645
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value
Stock options granted (in dollars per share)	$ 1.90	$ 2.99	$ 2.36
Amended and Restated Equity Incentive Plan and Non-related Plan Options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares
Balance at the beginning of the period (in shares)	1,479,000
Stock options granted (in shares)	375,000
Stock options cancelled/forfeited (in shares)	(248,000)
Stock options vested (in shares)	(915,000)
Balance at the end of the period (in shares)	691,000	1,479,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value
Balance at the beginning of the period (in dollars per share)	$ 1.24
Stock options granted (in dollars per share)	0.88
Stock options cancelled/forfeited (in dollars per share)	2.25
Stock options vested (in dollars per share)	0.80
Balance at the end of the period (in dollars per share)	$ 1.28	$ 1.24