Note 1 - Basis of Presentation - Revenues and Profit (Loss) Allocations to Reportable Segments (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenues	$ 4,847,000	$ 4,364,000
Net Income (Loss) Attributable to Parent, Total	269,000	29,000
Domestic Segment [Member]
Revenues	4,141,000	3,699,000
Net Income (Loss) Attributable to Parent, Total	276,000	73,000
Foreign Segment [Member]
Revenues	706,000	665,000
Net Income (Loss) Attributable to Parent, Total	$ (7,000)	$ (44,000)