REVENUE RECOGNITION (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, excluding assessed tax	$ 48,430	$ 44,707	$ 96,199	$ 84,277
Bile acid products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, excluding assessed tax	21,573	20,929	43,854	39,319
Tiopronin products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, excluding assessed tax	$ 26,857	$ 23,778	$ 52,345	$ 44,958
Geographic Concentration Risk | Revenue from Contract with Customer | United States
Disaggregation of Revenue [Line Items]
Concentration risk, percentage			95.00%