Summary of Significant Accounting Policies - Customers Who Represent 10% or More Of Total Revenues Or Accounts Receivable Balances (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Sales Revenue, Net | Customer Concentration Risk | AmerisourceBergen Drug Corporation
Concentrations and Significant Customer Information
Concentration risk, including more than 10% (percent)	22.00%	25.00%	34.00%
Sales Revenue, Net | Customer Concentration Risk | McKesson Corporation
Concentrations and Significant Customer Information
Concentration risk, including more than 10% (percent)	11.00%	11.00%	21.00%
Sales Revenue, Net | Customer Concentration Risk | Cardinal Health, Inc.
Concentrations and Significant Customer Information
Concentration risk, including more than 10% (percent)			15.00%
Sales Revenue, Net | Customer Concentration Risk | Takeda Pharmaceuticals Company Limited
Concentrations and Significant Customer Information
Concentration risk, including more than 10% (percent)	0.00%	12.00%	11.00%
Sales Revenue, Net | Geographic Concentration Risk
Concentrations and Significant Customer Information
Approximate percentage of revenues from customers outside the U.S. (percent)		12.00%
Accounts Receivable | Credit Concentration Risk | AmerisourceBergen Drug Corporation
Concentrations and Significant Customer Information
Concentration risk, including more than 10% (percent)	13.00%	43.00%
Accounts Receivable | Credit Concentration Risk | McKesson Corporation
Concentrations and Significant Customer Information
Concentration risk, including more than 10% (percent)	32.00%	10.00%