Note 9 - Other Financial Statement Information - Property, Plant, and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Land	$ 536	$ 536
Buildings and improvements	5,216	5,216
Machinery and equipment	20,168	20,046
Gross property, plant and equipment	25,920	25,798
Less: Accumulated depreciation	(21,886)	(21,667)
Property, plant and equipment, net	$ 4,034	$ 4,131

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount before accumulated depreciation of building structures held for productive use including addition, improvement, or renovation to the structure, including, but not limited to, interior masonry, interior flooring, electrical, and plumbing.

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