Note 5 - Property & Equipment - Property, Plant, and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Property, plant and equipment, gross	$ 52,078	$ 51,224
Less accumulated depreciation	36,029	35,346
Property and equipment, net	16,049	15,878
Land [Member]
Property, plant and equipment, gross	5,052	5,052
Land Improvements [Member]
Property, plant and equipment, gross	13,657	12,943
Building [Member]
Property, plant and equipment, gross	22,869	22,869
Machinery and Equipment [Member]
Property, plant and equipment, gross	10,398	10,360
Construction in Progress [Member]
Property, plant and equipment, gross	$ 102	$ 0