INTANGIBLE ASSETS - Amortization Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 13,231	$ 5,278	$ 324
Research and development expenses
Finite-Lived Intangible Assets [Line Items]
Amortization expense	697	823	324
Selling, general and administrative expenses
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 12,534	$ 4,455	$ 0