Convertible Senior Notes - Summary of Total Interest Expense Recognized Related To Convertible Senior Notes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
0% Convertible Senior Notes Due 2026
Debt Instrument [Line Items]
Amortization of debt discount and transaction costs	$ 4,886		$ 10,740
0.125% Convertible Senior Notes Due 2024
Debt Instrument [Line Items]
Amortization of debt discount and transaction costs	4,759	$ 4,521	14,100	$ 13,393
Total interest expense	4,900	4,662	14,522	13,815
0.125% Convertible Senior Notes Due 2024 | 0.125% coupon
Debt Instrument [Line Items]
Interest expense	141	141	422	422
1.50% Convertible Senior Notes Due 2022
Debt Instrument [Line Items]
Amortization of debt discount and transaction costs	4	1,057	630	3,134
Total interest expense	6	1,399	740	4,166
1.50% Convertible Senior Notes Due 2022 | 1.50% Coupon
Debt Instrument [Line Items]
Interest expense	$ 2	$ 342	$ 110	$ 1,032