Note 10 - Stockholders' Equity - Reconciliation of Activity in Stockholders' Equity Accounts (Details) - USD ($)	3 Months Ended				6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022
Balance		$ 33,426,000			$ 33,426,000
Shares repurchased	$ (30,451)				(31,762)
Net income (loss)	72,000		$ (363,000)		(766,000)	$ (940,000)
Balance	32,627,000				32,627,000
Common Stock [Member]
Balance	54,000	54,000	54,000	$ 54,000	54,000	54,000
Shares repurchased	0	0
Net income (loss)	0	0	0	0
Stock-based compensation expense			0	0
Balance	54,000	54,000	54,000	54,000	54,000	54,000
Additional Paid-in Capital [Member]
Balance	30,491,000	30,491,000	30,471,000	30,450,000	30,491,000	30,450,000
Shares repurchased		0
Net income (loss)	0	0	0	0
Stock-based compensation expense			20,000	21,000
Balance	30,491,000	30,491,000	30,491,000	30,471,000	30,491,000	30,491,000
Retained Earnings [Member]
Balance	1,977,000	2,777,000	(1,519,000)	(942,000)	2,777,000	(942,000)
Shares repurchased	(32,000)	(1,000)
Net income (loss)	80,000	(799,000)	(363,000)	(577,000)
Stock-based compensation expense			0	0
Balance	2,025,000	1,977,000	(1,882,000)	(1,519,000)	2,025,000	(1,882,000)
Noncontrolling Interest [Member]
Balance	65,000	104,000	0	0	104,000	0
Shares repurchased	0	0
Net income (loss)	(8,000)	(39,000)	0	0
Stock-based compensation expense			0	0
Balance	$ 57,000	$ 65,000	$ 0	$ 0	$ 57,000	$ 0