STOCK-BASED COMPENSATION - Non-Cash Stock-Based Compensation Expense (Details) - Service-Based Stock Options - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total non-cash stock-based compensation expense	$ 755	$ 654	$ 2,053	$ 1,973
Cost of goods sold
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total non-cash stock-based compensation expense	119	117	316	330
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total non-cash stock-based compensation expense	177	133	391	392
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total non-cash stock-based compensation expense	$ 459	$ 404	$ 1,346	$ 1,251