ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Product Shipments and Accounts Receivable, By Distributor (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Customer concentration risk | Consolidated revenue
Concentration Risk [Line Items]
Total	100.00%	100.00%	100.00%
Credit concentration risk | Accounts Receivable related to product sales
Concentration Risk [Line Items]
Total	100.00%	100.00%	100.00%
McKesson Corporation | Customer concentration risk | Consolidated revenue
Concentration Risk [Line Items]
Total	14.00%	36.00%	36.00%
McKesson Corporation | Credit concentration risk | Accounts Receivable related to product sales
Concentration Risk [Line Items]
Total	28.00%	41.00%	39.00%
AmerisourceBergen Corporation | Customer concentration risk | Consolidated revenue
Concentration Risk [Line Items]
Total	13.00%	27.00%	27.00%
AmerisourceBergen Corporation | Credit concentration risk | Accounts Receivable related to product sales
Concentration Risk [Line Items]
Total	28.00%	27.00%	33.00%
Cardinal Health | Customer concentration risk | Consolidated revenue
Concentration Risk [Line Items]
Total	11.00%	26.00%	25.00%
Cardinal Health | Credit concentration risk | Accounts Receivable related to product sales
Concentration Risk [Line Items]
Total	32.00%	23.00%	20.00%
Collegium | Customer concentration risk | Consolidated revenue
Concentration Risk [Line Items]
Total	55.00%	0.00%	0.00%
Collegium | Credit concentration risk | Accounts Receivable related to product sales
Concentration Risk [Line Items]
Total	0.00%	0.00%	0.00%
All others | Customer concentration risk | Consolidated revenue
Concentration Risk [Line Items]
Total	7.00%	11.00%	12.00%
All others | Credit concentration risk | Accounts Receivable related to product sales
Concentration Risk [Line Items]
Total	12.00%	9.00%	8.00%