FAIR VALUE MEASUREMENTS - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Business Acquisition [Line Items]
Fair value of convertible debt	$ 63,400
Change in fair value of contingent consideration	3,627	$ 3,344
Increase from revaluation of contingent consideration	(4,245)	(914)
Product Rights Chenodal
Business Acquisition [Line Items]
Increase from revaluation of contingent consideration		1,400
Acquired Product Rights Cholbam
Business Acquisition [Line Items]
Increase from revaluation of contingent consideration	1,800	1,100
Acquired Product Rights L-UDCA
Business Acquisition [Line Items]
Increase from revaluation of contingent consideration	$ 1,000	$ 800