Note 18 - Income Taxes - Summary of Deferred Income Tax Assets and Liabilities (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Compensation and benefit accruals	$ 525,000	$ 423,000
Inventory valuation	848,000	889,000
Federal and state net operating loss carryforwards	34,980,000	35,265,000
Deferred revenue	848,000	84,000
Interest limitation carryover	586,000	456,000
Defined benefit pension plan	305,000	449,000
Lease liabilities	673,000	865,000
Foreign deferred revenue and other provisions	2,657,000	2,367,000
Capitalized research and experimental costs	201,000	99,000
Other	381,000	599,000
Total	42,004,000	41,496,000
Domestic valuation allowance	(38,222,000)	(38,028,000)
Total deferred tax assets	3,782,000	3,468,000
Deferred tax liabilities:
Prepaid and other assets	(589,000)	(396,000)
Right-of-use assets, net	(536,000)	(705,000)
Total deferred tax liabilities	(1,125,000)	(1,101,000)
Net deferred tax asset	$ 2,657,000	$ 2,367,000