Note 5 - Property and Equipment - Property and Equipment (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Buildings	$ 493,000	$ 493,000
Machinery and equipment	15,273,000	13,039,000
Office furniture and equipment	2,177,000	2,076,000
Leasehold improvements	553,000	517,000
Software	3,000	3,000
Property, Plant and Equipment, Gross, Ending Balance	18,499,000	16,128,000
Less accumulated depreciation and amortization	(12,435,000)	(11,775,000)
Total net property and equipment	$ 6,064,000	$ 4,353,000