Debt (Details) - Convertible Debt - USD ($) $ in Thousands		Sep. 30, 2020	Dec. 31, 2019
Debt (Details) - Convertible Debt [Line Items]
Long-term Debt, Gross		$ 38,401	$ 52,658
4.875% Convertible Senior Notes Due 2020 [Member]
Debt (Details) - Convertible Debt [Line Items]
Long-term Debt, Gross		0	1,905
3.25% Convertible Senior Notes Due 2023 [Member]
Debt (Details) - Convertible Debt [Line Items]
Long-term Debt, Gross	[1]	$ 38,401	$ 50,753

[1] The amounts presented for the 3.25% convertible senior notes due 2023 within the table represent the fair value as of September 30, 2020 and December 31, 2019 (see Note 16 - Fair Value Measurements). The principal amount of these notes totaled $29.6 million and $37.6 million as of September 30, 2020 and December 31, 2019, respectively. The accrued, but unpaid, payment-in-kind interest is $1.0 million and $0.4 million as of September 30, 2020 and December 31, 2019, respectively.