Convertible Senior Notes - Expenses and Interest (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Amortization of debt issuance costs and discount on convertible senior notes	$ 3,018	$ 17,061	$ 9,006
3.75% Convertible Senior Notes
Debt Instrument [Line Items]
Interest expense	7,446
Amortization of debt issuance costs and discount on convertible senior notes	1,670
Total	$ 9,116
Effective interest rate (as a percent)	4.50%