Convertible Senior Notes - Summary of the Components of Interest Expense (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Amortization of discount on convertible senior notes	$ 4,766	$ 0	$ 0
Amortization of debt issuance costs	1,597	$ 2,204	$ 2,292
Convertible Senior Notes \| Convertible Debt
Debt Instrument [Line Items]
Contractual coupon interest	379
Amortization of discount on convertible senior notes	4,766
Amortization of debt issuance costs	$ 600

Amount of noncash expense included in interest expense to amortize debt discount and premium associated with the related debt instruments. Excludes amortization of financing costs. Alternate captions include noncash interest expense.

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Amount of amortization expense attributable to debt issuance costs.

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