Note 10 - Shareholders' Equity - Information About Stock Options (Details)	12 Months Ended
	Dec. 31, 2021 USD ($) $ / shares shares
Range of Exercise Prices, Upper Limit (in dollars per share)	$ 3.90
Options Outstanding, Options (in shares) | shares	427,580
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 3.50
Options Outstanding, Weighted Average Remaining Contract Life (Year)	1 year 10 months 28 days
Options Outstanding, Aggregate Intrinsic Value | $	$ 1,056,000
Options Exercisable, Options (in shares) | shares	315,583
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 3.47
Options Exercisable, Weighted Average Remaining Contract Life (Year)	1 year 9 months 7 days
Options Exercisable, Aggregate Intrinsic Value | $	$ 790,000