Note 5 - Property & Equipment - Property, Plant, and Equipment (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Property, plant and equipment, gross	$ 51,402	$ 51,224
Less accumulated depreciation	35,836	35,346
Property and equipment, net	15,566	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	10,398	10,360
Construction in Progress [Member]
Property, plant and equipment, gross	$ 140	$ 0