Convertible Notes and Credit Facilities - Convertible Roll Forwards 2024 Notes (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Sep. 27, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Carrying amount	$ 88,629		$ 114,808
Convertible Note due 2024 [Member]
Debt Instrument [Line Items]
Principal amount	115,500	$ 115,500
Less: Debt discount, net of amortization	(23,652)
Less: Debt issuance costs, net of amortization	(3,219)
Carrying amount	$ 88,629
Remaining amortization period (years)	4 years 7 months 31 days
Effective interest rate on liability component	7.95%

Carrying amount of long-term convertible debt as of the balance sheet date, net of the amount due in the next twelve months or greater than the normal operating cycle, if longer. The debt is convertible into another form of financial instrument, typically the entity's common stock.

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Remaining amortization period for discount on the liability component of convertible debt which may be settled in cash upon conversion, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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

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- Definition

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

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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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No definition available.

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Amount, after accumulated amortization, of debt discount.

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The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

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