Note 6 - Supplemental Balance Sheet Information - Components of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Property, plant and equipment, gross	$ 85,311	$ 85,353
Less: Accumulated depreciation	(63,272)	(62,828)
Property, plant and equipment, net	22,039	22,525
Land [Member]
Property, plant and equipment, gross	1,273	1,273
Building and Building Improvements [Member]
Property, plant and equipment, gross	8,096	8,148
Machinery and Equipment [Member]
Property, plant and equipment, gross	62,239	62,562
Furniture and Fixtures [Member]
Property, plant and equipment, gross	2,105	2,112
Computer Equipment [Member]
Property, plant and equipment, gross	6,520	6,528
Construction in Progress [Member]
Property, plant and equipment, gross	$ 5,078	$ 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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