Debt - Schedule of Convertible Senior Notes (Details) - Convertible Debt - USD ($)	Mar. 31, 2021	Dec. 31, 2020	Aug. 31, 2019	May 31, 2018
2027 Notes
Liability component:
Principal	$ 1,150,000,000	$ 1,150,000,000	$ 1,150,000,000.0
Less: debt discount and issuance costs, net of amortization	(189,600,000)	(196,359,000)
Net carrying amount	960,400,000	953,641,000
Equity component:	220,529,000	220,529,000
2025 Notes
Liability component:
Principal	1,150,000,000	1,150,000,000		$ 1,150,000,000.0
Less: debt discount and issuance costs, net of amortization	(186,571,000)	(196,934,000)
Net carrying amount	963,429,000	953,066,000
Equity component:	$ 285,225,000	$ 285,225,000