Including the current and noncurrent portions, carrying value as of the balance sheet date of a written promise to pay a note, initially due after one year or beyond the operating cycle if longer, which can be exchanged for a specified amount of one or more securities (typically common stock), at the option of the issuer or the holder.

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Convertible Senior Notes (Details) $ in Thousands	3 Months Ended	6 Months Ended
Convertible Senior Notes (Details) $ in Thousands	Sep. 30, 2018 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Debt Instrument, Redemption [Line Items]
Convertible senior notes		$ 270,437		$ 269,634
Convertible Debt, 2017 Issuance [Member]
Debt Instrument, Redemption [Line Items]
Proceeds from convertible senior notes	$ 139,500
Convertible senior notes conversion ratio		0.0507073
Convertible Debt, 2017 Issuance [Member] \| Convertible Debt [Member]
Debt Instrument, Redemption [Line Items]
Convertible senior notes interest rate per annum		5.625%
Convertible Debt, 2017 Issuance [Member] \| Convertible Debt [Member] \| Private Placement [Member]
Debt Instrument, Redemption [Line Items]
Convertible senior notes aggregate principal amount		$ 125,000
Convertible Debt, 2017 Issuance [Member] \| Convertible Debt [Member] \| Over-Allotment Option [Member]
Debt Instrument, Redemption [Line Items]
Convertible senior notes aggregate principal amount		$ 18,800
Convertible Debt, 2018 Issuance [Member]
Debt Instrument, Redemption [Line Items]
Proceeds from convertible senior notes			$ 127,700
Convertible senior notes conversion ratio		0.0488496
Convertible Debt, 2018 Issuance [Member] \| Convertible Debt [Member]
Debt Instrument, Redemption [Line Items]
Convertible senior notes interest rate per annum		6.375%
Convertible Debt, 2018 Issuance [Member] \| Convertible Debt [Member] \| Private Placement [Member]
Debt Instrument, Redemption [Line Items]
Convertible senior notes aggregate principal amount		$ 131,600