Note 1 - Basis of Presentation - Revenues and Profit (Loss) Allocations to Reportable Segments (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Revenues	$ 4,828,000	$ 4,099,000	$ 14,709,000	$ 12,939,000
Net income (loss)	316,000	33,000	1,082,000	(25,000)
Domestic Segment [Member]
Revenues	4,101,000	3,477,000	12,382,000	10,892,000
Net income (loss)	284,000	34,000	1,093,000	(1,000)
Foreign Segment [Member]
Revenues	727,000	622,000	2,327,000	2,047,000
Net income (loss)	$ 32,000	$ (1,000)	$ (11,000)	$ (24,000)