Note 7 - Commitments and Contingencies - Supplemental Lease Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Right-of-use asset, net and lease liabilities (in thousands)	$ 3,955	$ 2,889
Cash paid for operating lease liabilities (in thousands)	$ 1,239	$ 1,052
Weighted average remaining lease term (years) (Year)	3 years 6 months	3 years 6 months
Weighted average discount rate	4.10%	3.80%
Lease expense	$ 1,239	$ 1,052
Cost of Sales [Member]
Lease expense	892	725
General and Administrative Expense [Member]
Lease expense	272	214
Research and Development Expense [Member]
Lease expense	$ 75	$ 113