Basis of Presentation and Summary of Significant Accounting Policies - Concentration and Significant Customer Information (Details)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Sales Revenue, Net | Customer Concentration Risk | AmerisourceBergen Drug Corporation
Concentrations and Significant Customer Information
Concentration risk (as a percent)	19.00%	22.00%	21.00%	23.00%
Sales Revenue, Net | Customer Concentration Risk | McKesson Corporation
Concentrations and Significant Customer Information
Concentration risk (as a percent)	21.00%	10.00%	18.00%	10.00%
Sales Revenue, Net | Customer Concentration Risk | Caremark LLC (Specialty Pharmacy)
Concentrations and Significant Customer Information
Concentration risk (as a percent)	0.00%	10.00%	0.00%	10.00%
Accounts Receivable | Credit Concentration Risk | AmerisourceBergen Drug Corporation
Concentrations and Significant Customer Information
Concentration risk (as a percent)			22.00%		13.00%
Accounts Receivable | Credit Concentration Risk | McKesson Corporation
Concentrations and Significant Customer Information
Concentration risk (as a percent)			21.00%		32.00%