Summary of Significant Accounting Policies - Convertible Senior Notes (Details) - Convertible Debt - USD ($)	1 Months Ended
	Nov. 30, 2020	Dec. 31, 2021	May 31, 2021	Nov. 15, 2020	Jun. 30, 2019	Jun. 01, 2019	Feb. 28, 2018	Feb. 15, 2018
Convertible Senior Notes Due June 2026
Debt Instrument [Line Items]
Principal amount					$ 316,300,000	$ 316,250,000
Convertible Notes Due November 2025
Debt Instrument [Line Items]
Principal amount	$ 350,000,000			$ 350,000,000
Amount issued due to exchange	210,700,000
Additional principal amount issued	139,300,000
Convertible Senior Notes Due February 2023
Debt Instrument [Line Items]
Principal amount		$ 10,900,000					$ 230,000,000	$ 230,000,000
Extinguishment of Debt, Amount	181,900,000
Amount issued due to exchange	$ 210,700,000
Repurchased principal amount			$ 37,100,000