Debt - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020	Jul. 17, 2020
Long-term debt
Amortization of debt issuance costs	$ 452	$ 256
Effective interest rate of the liability component	10.60%		11.00%
Convertible debt \| 3.00% Convertible senior notes due 2022
Long-term debt
Contractual interest expense	$ 1,110	1,119
Amortization of debt issuance costs	175	111
Amortization of debt discount		2,225
Total	$ 1,285	$ 3,455
Effective interest rate of the liability component	3.50%	11.00%
Convertible debt \| 1.50% Convertible senior notes due 2026
Long-term debt
Contractual interest expense	$ 1,069	$ 1,076
Amortization of debt issuance costs	277	124
Amortization of debt discount		3,234
Total	$ 1,346	$ 4,434
Effective interest rate of the liability component	1.90%	10.20%

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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Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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Amount of the cost of borrowed funds accounted for as interest expense for debt.

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Represents the portion of interest incurred in the period on debt arrangements that was charged against earnings, excluding amortization of debt discount (premium) and financing costs.

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