Convertible Senior Notes - Balance of Convertible Notes (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Nov. 15, 2018
Debt Instrument
Total Convertible Notes, net	$ 160,746	$ 158,213
Convertible Debt \| Convertible Notes
Debt Instrument
Convertible Notes initially issued	210,000	210,000	$ 210,000
Unamortized discount	(45,329)	(47,660)
Unamortized issuance costs attributable to principal amount	(3,925)	(4,127)
Total Convertible Notes, net	160,746	$ 158,213
Fair value of outstanding Convertible Notes	$ 190,100

Face (par) amount of debt instrument at time of issuance.

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Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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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 (premium).

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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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Carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion. Senior note holders are paid off in full before any payments are made to junior note holders.

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