Long Term Debt - Interest Expense Related to Convertible Senior Notes (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Debt Instrument [Line Items]
Non-cash amortization of debt discount			$ 1,867	$ 127
1.50% Convertible Senior Notes
Debt Instrument [Line Items]
Coupon interest	$ 625	$ 0	625	0
Non-cash amortization of debt discount	1,740	0	1,740	0
Amortization of deferred financing costs	204	0	204	0
Convertible senior notes interest expense	$ 2,569	$ 0	$ 2,569	$ 0

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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