Note 3 - Summary of Significant Accounting Policies - Supplement Information Related to Operating Leases (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($)
Operating cash flows used for operating leases (in thousands of U.S. dollars)	$ 91
Right-of-use assets obtained in exchange for new lease liabilities (in thousands of U.S. dollars)	$ 10
Weighted-average remaining lease term (Year)	1 year 76 days
Weighted-average discount rate	6.00%