Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Narrative (Details)

v3.21.1
Fair Value Measurements - Narrative (Details) - USD ($)
$ in Millions
Mar. 31, 2021
Dec. 31, 2020
Convertible Notes due 2023    
Fair Value Measurements    
Debt instrument, fair value disclosure $ 419.7 $ 460.8
Convertible Notes due 2023 | Carrying Value    
Fair Value Measurements    
Convertible notes 340.5 316.6
Convertible Notes due 2025    
Fair Value Measurements    
Debt instrument, fair value disclosure 519.1 540.8
Convertible Notes due 2025 | Carrying Value    
Fair Value Measurements    
Convertible notes $ 504.7 $ 439.9