Note D - Income Taxes - Reconciliation of the Effective Income Tax Rate (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income taxes at statutory federal income tax rate	$ 1,266,000	$ 1,148,000
Income taxes at statutory federal income tax rate of 34%, percent	21.00%	21.00%
Nondeductible expenses	$ 1,000	$ 1,000
Nondeductible expenses, percent
Research & development credits	$ (8,000)	$ (20,000)
Research & development credits, percent	(0.10%)	(0.30%)
Non-taxable dividends	$ (2,000)	$ (6,000)
Non-taxable dividends, percent		(0.10%)
Other, net	$ 12,000	$ (9,000)
Other, net, percent	0.20%	(0.20%)
Provision for income taxes	$ 1,268,659	$ 1,113,523
Provision for income taxes, percent	21.10%	20.40%