Note 9 - Non-recourse Long-term Debt, Net - Summary of Royalty-backed Loan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current portion of debt, net	$ 7,117	$ 5,419
Long-term debt, net	31,910	39,180
Royalty-backed Loan [Member]
Outstanding principal balance, current portion	7,349	5,688
Unamortized debt discount, current portion	(232)	(269)
Current portion of debt, net	7,117	5,419
Outstanding principal balance, long-term portion	32,170	39,674
Unamortized debt discount, long-term portion	(260)	(494)
Long-term debt, net	31,910	39,180
Interest expense	4,131	4,660
Non-cash interest expense	271	302
Total interest expense included in interest (expense) income, net	$ 4,402	$ 4,962	$ 5,100