Note 9 - Operating Leases - Supplemental Balance Sheet Information Related to Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Weighted-average remaining lease term (years) (Year)	3 years 3 months 18 days	3 years 8 months 12 days
Weighted-average discount rate	4.50%	4.50%
Other Noncurrent Assets [Member]
Operating lease right-of-use asset	$ 2,189	$ 1,866
Accrued Expenses and Other Current Liabilities [Member]
Current operating lease liability	680	620
Other Noncurrent Liabilities [Member]
Operating lease liability, net of current portion	1,524	1,247
Accrued Expenses and Other Current Liabilites and Other Noncurrent Liabilities [Member]
Total operating lease liability	$ 2,204	$ 1,867