Note 5 - Supplemental Balance Sheet Information - Components of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Property, plant and equipment, gross	$ 91,797	$ 91,423
Less: Accumulated depreciation	(69,024)	(68,218)
Property, plant and equipment, net	22,773	23,205
Land [Member]
Property, plant and equipment, gross	1,273	1,273
Building and Building Improvements [Member]
Property, plant and equipment, gross	15,443	15,442
Machinery and Equipment [Member]
Property, plant and equipment, gross	64,137	63,780
Furniture and Fixtures [Member]
Property, plant and equipment, gross	2,654	2,588
Computer Equipment [Member]
Property, plant and equipment, gross	7,586	7,579
Construction in Progress [Member]
Property, plant and equipment, gross	$ 704	$ 761

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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