Current and Long-Term Debt - Convertible Notes Interest Expense (Details) - Convertible Senior Notes 1.00 percent due December 2020 - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Long-Term Debt
Cash interest per contractual coupon rate	$ 719	$ 719
Amortization of note discount	2,929	2,780
Amortization of debt issuance costs	228	206
Total interest expense related to Convertible Notes	$ 3,876	$ 3,705

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

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