Debt - Reconciliation of Convertible Debt (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Sep. 30, 2019
Debt Instrument [Line Items]
Carrying value	$ 234,527,000	$ 210,373,000
Convertible Senior Notes Due 2024 | Convertible debt
Debt Instrument [Line Items]
Gross proceeds	316,250,000	316,250,000		$ 316,250,000
Unamortized debt discount	(78,395,000)	(101,565,000)
Unamortized issuance costs	(3,328,000)	(4,312,000)	$ (5,500,000)
Carrying value	$ 234,527,000	$ 210,373,000