Note 10 - Non-recourse Long-term Debt, Net - Summary of Royalty-backed Loan (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Current portion of debt, net	$ 7,240		$ 7,117
Long-term debt, net	30,166		31,910
Royalty-backed Loan [Member]
Outstanding principal balance, current portion	7,456		7,349
Unamortized debt discount, current portion	(216)		(232)
Current portion of debt, net	7,240		7,117
Outstanding principal balance, long-term portion	30,381		32,170
Unamortized debt discount, long-term portion	(215)		(260)
Long-term debt, net	30,166		$ 31,910
Interest expense	939	$ 1,077
Non-cash interest expense	61	71
Total interest expense included in interest (expense) income, net	$ 1,000	$ 1,148