Note D - Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets
Accounts receivable	$ 4,456	$ 5,760
Inventories	9,104	14,163
Accrued expenses	157,610	234,594
Total deferred tax assets	171,170	254,517
Deferred tax liabilities
Depreciation on property, plant and equipment	(81,145)	(161,657)
Unrealized gain on marketable securities	(123,880)	(90,478)
Total deferred tax liabilities	(205,025)	(252,135)
Net deferred tax liability	$ (33,855)
Net deferred tax asset		$ 2,382