Debt - Equity and Liability Components of the Notes (Details) - USD ($)	Dec. 31, 2019	Apr. 15, 2019
Debt Instrument [Line Items]
Less: Issuance costs	$ (1,100,000)
Convertible Debt
Debt Instrument [Line Items]
Principal amount of 2024 Notes outstanding	80,000,000	$ 80,000,000.0
Unamortized discount (including unamortized debt issuance cost)	(18,955,000)
Total notes payable	61,045,000
Equity component of notes	17,624,000
Less: Deferred tax liability	(4,065,000)
Less: Issuance costs	(1,094,000)
Capital in excess of Par Value	$ 12,465,000