Note 7 - Property, Plant and Equipment, Net - Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Property, plant and equipment, gross	$ 150,183	$ 146,749
Accumulated depreciation	(114,630)	(112,248)
Property, plant and equipment, net	35,553	34,501
Land [Member]
Property, plant and equipment, gross	1,108	1,115
Building and Building Improvements [Member]
Property, plant and equipment, gross	20,919	19,917
Machinery and Equipment [Member]
Property, plant and equipment, gross	125,895	124,114
Construction in Progress [Member]
Property, plant and equipment, gross	$ 2,261	$ 1,603

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, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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