Convertible Senior Notes - Summary of Total Interest Expense Recognized Related To Convertible Senior Notes (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
0% Convertible Senior Notes Due 2026
Debt Instrument [Line Items]
Amortization of debt discount and transaction costs	$ 4,798		$ 5,854
0.125% Convertible Senior Notes Due 2024
Debt Instrument [Line Items]
Amortization of debt discount and transaction costs	4,702	$ 4,466	9,341	$ 8,872
Total interest expense	4,842	4,606	9,622	9,153
0.125% Convertible Senior Notes Due 2024 \| 0.125% coupon
Debt Instrument [Line Items]
Interest expense	140	140	281	281
1.50% Convertible Senior Notes Due 2022
Debt Instrument [Line Items]
Amortization of debt discount and transaction costs	8	1,047	626	2,077
Total interest expense	10	1,392	734	2,767
1.50% Convertible Senior Notes Due 2022 \| 1.50% Coupon
Debt Instrument [Line Items]
Interest expense	$ 2	$ 345	$ 108	$ 690

Amount of amortization expense attributable to debt discount (premium) and debt issuance costs.

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