Note 5 - Supplemental Balance Sheet Information - Components of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property, plant and equipment, gross	$ 88,070	$ 85,353
Less – Accumulated depreciation	(65,220)	(62,828)
Total	22,850	22,525
Land [Member]
Property, plant and equipment, gross	1,273	1,273
Building and Building Improvements [Member]
Property, plant and equipment, gross	15,393	15,386
Machinery and Equipment [Member]
Property, plant and equipment, gross	61,048	55,058
Furniture and Fixtures [Member]
Property, plant and equipment, gross	2,235	2,194
Computer Equipment [Member]
Property, plant and equipment, gross	6,894	6,712
Construction in Progress [Member]
Property, plant and equipment, gross	$ 1,227	$ 4,730

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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