Debt - Outstanding Convertible Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Liability component:
Total long-term debt	$ 289,334	$ 277,034
Convertible Debt | 2022 Convertible Notes
Liability component:
Principal	320,000
Less: debt discount and issuance costs, net	30,666
Total long-term debt	289,334	$ 277,034
Gross equity component	$ 72,576