Note 9 - Income Taxes - Income Tax Reconciliation (Details) - USD ($)		12 Months Ended
		Dec. 31, 2025	Dec. 31, 2024
Expected federal tax		$ 439,000	$ 443,000
Expected federal tax, percent		21.00%	21.00%
Permanent differences		$ 27,000	$ 7,000
Permanent differences, percent		1.30%	0.30%
State income tax, net of federal tax benefit	[1]	$ 41,000	$ 37,000
State income tax, net of federal tax benefit, percent	[1]	2.00%	1.80%
Foreign tax credit		$ 0	$ 0
Foreign tax credit, percent		0.00%	0.00%
Benefit valuation allowance		$ 0	$ 0
Benefit valuation allowance, percent		0.00%	0.00%
Research and Development tax credit		$ (65,000)	$ 21,000
Research and Development tax credit, percent		(3.10%)	1.00%
Total income tax expense		$ 462,000	$ 532,500
Total, percent		22.20%	25.30%
Other Income Tax Authority [Member]
Other		$ 20,000	$ 24,500
Other, percent		1.00%	1.20%

[1] The tax effect in this category primarily reflects the state and local taxes in Iowa, Oklahoma and California.