Convertible Subordinated Notes Convertible Subordinated Notes (Liability and Equity Components) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Accumulated Amortization, Debt Issuance Costs	$ 4,442	$ 4,138
Principal amount	90,764
Unamortized discount of liability component	(319)
Debt Issuance Costs, Net	1,618	955
Convertible subordinated notes due 2021	5,971	5,732
Convertible subordinated notes
Debt Instrument [Line Items]
Accumulated Amortization, Debt Issuance Costs	130	106
Principal amount	6,319	6,346
Unamortized discount of liability component	(319)	(560)
Debt Issuance Costs, Net	29	54
Convertible subordinated notes due 2021	5,971	5,732
Carrying value of the equity component	$ 789	$ 789

Amount of accumulated amortization of debt issuance costs.

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The portion of the carrying value of convertible subordinated debt as of the balance sheet date that is scheduled to be repaid after one year or beyond the normal operating cycle if longer. This form of debt can be exchanged for a specified amount of another security, typically the entity's common stock, at the option of the issuer or the holder, and places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets.

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The carrying amount of the equity component of convertible debt which may be settled in cash upon conversion.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount, after accumulated amortization, of debt discount.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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