Note 5 - Supplemental Balance Sheet Information - Components of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 29, 2019	Sep. 30, 2020	Sep. 29, 2019	Dec. 31, 2019
Property, plant and equipment, gross	$ 87,160		$ 87,160		$ 85,353
Less: Accumulated depreciation	(64,555)		(64,555)		(62,828)
Property, plant and equipment, net	22,605		22,605		22,525
Depreciation	582	$ 586	1,743	$ 1,548
Land [Member]
Property, plant and equipment, gross	1,273		1,273		1,273
Building and Building Improvements [Member]
Property, plant and equipment, gross	15,365		15,365		15,386
Machinery and Equipment [Member]
Property, plant and equipment, gross	55,869		55,869		55,058
Furniture and Fixtures [Member]
Property, plant and equipment, gross	2,219		2,219		2,194
Computer Equipment [Member]
Property, plant and equipment, gross	6,812		6,812		6,712
Construction in Progress [Member]
Property, plant and equipment, gross	$ 5,622		$ 5,622		$ 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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