Note 12 - Income Taxes - Deferred Tax Assets (Liabilities) (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Inventories	$ 176,022	$ 221,441
Bad debts	23,197	5,757
Accrued liabilities	527,320	677,728
Prepaid expense	(103,037)	(136,419)
Depreciation and amortization	(2,464,503)	(3,111,224)
Capitalized Costs	496,897	629,085
Research and development and other credit carryforwards	1,067,816	443,689
Right of use lease accounting	(149,876)	(80,376)
Directors stock option plan	203,914	180,761
Total deferred tax liability	(222,250)	(1,169,558)
Valuation allowance	(33,000)	(39,000)
Reserve for uncertain tax positions	(55,000)	(176,000)
Total reserves & allowances	(88,000)	(215,000)
Net deferred tax liability, net of reserves	$ (310,250)	$ (1,384,558)