SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Customers Who Represent 10% or More of Total Revenues or Accounts Receivable Balances (Details) - facility	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue from Contract with Customer | Customer Concentration Risk | McKesson Corporation
Concentrations and Significant Customer Information
Concentration risk, including less than and more than 10% (percent)	36.00%	26.00%	24.00%
Revenue from Contract with Customer | Customer Concentration Risk | AmerisourceBergen Drug Corporation
Concentrations and Significant Customer Information
Concentration risk, including less than and more than 10% (percent)	28.00%	27.00%	26.00%
Revenue from Contract with Customer | Customer Concentration Risk | Cardinal Health
Concentrations and Significant Customer Information
Concentration risk, including less than and more than 10% (percent)	13.00%	10.00%	10.00%
Accounts Receivable | Customer Concentration Risk | Three Customers
Concentrations and Significant Customer Information
Concentration risk, including less than and more than 10% (percent)	85.00%
Accounts Receivable | Customer Concentration Risk | Two Customers
Concentrations and Significant Customer Information
Concentration risk, including less than and more than 10% (percent)		73.00%
Feraheme
Concentrations and Significant Customer Information
Number of production facilities	2