Basis of Presentation and Summary of Significant Accounting Policies - Concentration and Significant Customer Information (Details) - facility	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Sales Revenue, Goods, Net | Customer Concentration Risk | AmerisourceBergen Drug Corporation
Concentrations and Significant Customer Information
Concentration risk	24.00%	28.00%	26.00%	26.00%
Sales Revenue, Goods, Net | Customer Concentration Risk | McKesson Corporation
Concentrations and Significant Customer Information
Concentration risk	25.00%	26.00%	26.00%	23.00%
Accounts Receivable | Customer Concentration Risk | Four customers
Concentrations and Significant Customer Information
Concentration risk			74.00%
Accounts Receivable | Customer Concentration Risk | Two customers
Concentrations and Significant Customer Information
Concentration risk					57.00%
Feraheme
Concentrations and Significant Customer Information
Number of production facilities			2