Note 5 - Property & Equipment - Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Property, plant and equipment, gross	$ 51,224	$ 51,224
Less accumulated depreciation	35,599	35,346
Property and equipment, net	15,625	15,878
Land [Member]
Property, plant and equipment, gross	5,052	5,052
Land Improvements [Member]
Property, plant and equipment, gross	12,943	12,943
Building [Member]
Property, plant and equipment, gross	22,869	22,869
Machinery and Equipment [Member]
Property, plant and equipment, gross	$ 10,360	$ 10,360