STOCKHOLDERS' EQUITY AND SHARE-BASED COMPENSATION EXPENSE - Share-based compensation expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Recognized share-based compensation expense [Abstract]
Total stock-based compensation expense	$ 14,985	$ 12,411	$ 7,727
Costs of product sales [Member]
Recognized share-based compensation expense [Abstract]
Total stock-based compensation expense	2,620	2,500	1,002
Research and development [Member]
Recognized share-based compensation expense [Abstract]
Total stock-based compensation expense	1,951	2,266	1,331
Selling, general and administrative [Member]
Recognized share-based compensation expense [Abstract]
Total stock-based compensation expense	$ 10,414	$ 7,645	$ 5,394