ACCRUED EXPENSES (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Government rebates payable	$ 7,099	$ 6,967
Compensation related costs	4,170	7,441
Accrued royalties and contingent consideration	5,124	5,766
Research and development	8,845	7,311
Selling, general and administrative	2,630	3,333
Miscellaneous accrued	2,324	2,490
Accrued expenses	$ 30,192	$ 33,308