Long-term Debt - Interest Expense on Note (Details) - Senior Notes [Member] - Convertible Senior Notes Due 2023 - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Coupon interest	$ 3,414	$ 1,043
Amortization of debt discount	3,773	1,111
Amortization of debt issuance costs	824	252
Total interest expense recognized	$ 8,011	$ 2,406