Note 9 - Leases - Lease Assets and Liabilities (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2019
Operating Lease, Right-of-Use Asset	$ 130,000	$ 395,000	$ 629,000
Accrued Liabilities [Member]
Current operating lease liabilities	132,000	268,000
Other Noncurrent Liabilities [Member]
Noncurrent operating lease liabilities		132,000
Accrued Liabilities and Other Noncurrent Liabilities [Member]
Operating Lease, Liability, Total	$ 132,000	$ 400,000	$ 629,000