Convertible Senior Notes - Summary of Fair Value and Carrying Value of Convertible Senior Notes (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
0% Convertible Senior Notes Due 2026 | Fair Value
Debt Instrument [Line Items]
Convertible senior notes	$ 383,400
0% Convertible Senior Notes Due 2026 | Carrying Value
Debt Instrument [Line Items]
Convertible senior notes	267,878
0.125% Convertible Senior Notes Due 2024 | Fair Value
Debt Instrument [Line Items]
Convertible senior notes	616,500	$ 663,615
0.125% Convertible Senior Notes Due 2024 | Carrying Value
Debt Instrument [Line Items]
Convertible senior notes	378,373	369,032
1.50% Convertible Senior Notes Due 2022 | Fair Value
Debt Instrument [Line Items]
Convertible senior notes	1,224	265,488
1.50% Convertible Senior Notes Due 2022 | Carrying Value
Debt Instrument [Line Items]
Convertible senior notes	$ 282	$ 72,482