Convertible Senior Notes - Summary of Total Interest Expense Recognized Related To Convertible Senior Notes (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
0.125% Convertible Senior Notes Due 2024
Debt Instrument [Line Items]
Amortization of debt discount and transaction costs	$ 827
Total interest expense	854
0.125% Convertible Senior Notes Due 2024 \| 0.125% coupon
Debt Instrument [Line Items]
Interest expense	27
1.50% Convertible Senior Notes Due 2022
Debt Instrument [Line Items]
Amortization of debt discount and transaction costs	4,884	$ 4,616
Total interest expense	6,593	6,341
1.50% Convertible Senior Notes Due 2022 \| 1.50% Coupon
Debt Instrument [Line Items]
Interest expense	$ 1,709	$ 1,725

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

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