Note 8 - Leases - Lease Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Operating lease right-of-use assets	$ 678	$ 130
Accrued Liabilities [Member]
Current operating lease liabilities	183	132
Other Noncurrent Liabilities [Member]
Noncurrent operating lease liabilities	495
Accrued Liabilities and Other Noncurrent Liabilities [Member]
Operating Lease, Liability, Total	$ 678	$ 132