Fair Value Measurements - Fair Value Inputs, Liabilities, Quantitative Information (Details) $ in Thousands	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Contingent Consideration
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Contingent consideration liability	$ 82,236	$ 10,956	$ 683
Revenue-based Payments | Contingent Consideration
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Contingent consideration liability	10,661	10,956
Supply chain milestone | Contingent Consideration
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Contingent consideration liability	13,593
Revenue milestones
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Contingent consideration liability	57,982
Other Payments
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Contingent consideration asset	$ 607
Other Payments | Contingent Consideration
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Contingent consideration asset		$ 760
Measurement Input, Discount Rate | Revenue-based Payments | Minimum | Discounted Cash Flow | Fair Value, Inputs, Level 3
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Unobservable inputs, contingent liability	0.099	0.099
Measurement Input, Discount Rate | Revenue-based Payments | Maximum | Discounted Cash Flow | Fair Value, Inputs, Level 3
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Unobservable inputs, contingent liability	0.25	0.15
Measurement Input, Discount Rate | Supply chain milestone | Contingent Consideration | Discounted Cash Flow | Fair Value, Inputs, Level 3
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Unobservable inputs, contingent liability	0.053
Measurement Input, Discount Rate | Revenue milestones | Minimum | Discounted Cash Flow | Fair Value, Inputs, Level 3
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Unobservable inputs, contingent liability	0.03
Measurement Input, Discount Rate | Revenue milestones | Maximum | Discounted Cash Flow | Fair Value, Inputs, Level 3
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Unobservable inputs, contingent liability	0.13
Measurement Input, Discount Rate | Other Payments | Discounted Cash Flow | Fair Value, Inputs, Level 3
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Unobservable inputs, contingent receivable asset	0.10
Measurement Input, Discount Rate | Other Payments | Contingent Consideration | Discounted Cash Flow | Fair Value, Inputs, Level 3
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Unobservable inputs, contingent receivable asset		0.10
Milestone Payment Probability | Supply chain milestone | Contingent Consideration | Discounted Cash Flow | Fair Value, Inputs, Level 3
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Unobservable inputs, contingent liability	0.95
Milestone Payment Probability | Other Payments | Discounted Cash Flow | Fair Value, Inputs, Level 3
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Unobservable inputs, contingent receivable asset	0.67
Milestone Payment Probability | Other Payments | Contingent Consideration | Discounted Cash Flow | Fair Value, Inputs, Level 3
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Unobservable inputs, contingent receivable asset		0.75