Fair Value Measurements - Narrative (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current portion of contingent consideration	$ 25,600,000	$ 32,300,000
Brabant Pharma Limited
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Potential contingent payment, minimum	0
Potential contingent payment, maximum	75,000,000.0
Current portion of contingent consideration	25,600,000
Business Combination, Contingent Consideration, Liability	$ 38,200,000
Warrants From July 2011 Debt Financing [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of common stock that can be purchased (shares)	28,125
Exercise price of warrants (in usd per share)	$ 72.00

For contingent consideration arrangements recognized in connection with a business combination, this element represents an estimate of the high-end of the potential range (undiscounted) of the consideration which may be paid.

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For contingent consideration arrangements and indemnification assets recognized in connection with a business combination, this element represents an estimate of the low-end of the potential range (undiscounted) of the consideration which may be paid.

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Amount of liability recognized arising from contingent consideration in a business combination.

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Exercise price per share or per unit of warrants or rights outstanding.

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