Note 15 - Income Taxes - Components of Company's Deferred Tax Assets and Liabilities for Federal and State Income Taxes (Details) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Net operating loss carryforwards	$ 26,465,000	$ 27,088,000
Income tax credit carryforwards	2,738,000	2,797,000
Stock compensation	421,000	437,000
Lease obligation	908,000	127,000
Deferred revenue	251,000	313,000
Inventory Reserve	517,000	449,000
Sec. 174 Capitalized R&D	317,000	0
Other	159,000	213,000
Total deferred tax assets	31,776,000	31,424,000
Depreciation and amortization	(252,000)	(320,000)
Lease asset	(824,000)	(120,000)
Total deferred tax liabilities	(1,076,000)	(440,000)
Valuation allowance	(30,700,000)	(30,984,000)
Net deferred taxes	$ 0	$ 0