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Fair Value Measurements - Additional Information (Details) - Reported Value Measurement - Convertible Debt - Level 2 - USD ($)
$ in Millions
Dec. 31, 2019
Dec. 31, 2018
Convertible Senior Notes due 2023    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, fair value $ 310.3 $ 279.1
Convertible Senior Notes due 2026    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, fair value $ 522.2