Note 5 - Property, Equipment and Improvements - Major Classes of Property, Equipment and Improvements (Details) - USD ($) $ in Thousands	Apr. 02, 2017	Dec. 31, 2016
Property, Plant, and Equipment, Gross	$ 65,780	$ 65,193
Less-accumulated depreciation	(57,709)	(57,194)
Net property, equipment and improvements	8,071	7,999
Land [Member]
Property, Plant, and Equipment, Gross	123	123
Building and Building Improvements [Member]
Property, Plant, and Equipment, Gross	7,770	7,757
Machinery and Equipment [Member]
Property, Plant, and Equipment, Gross	50,146	49,722
Furniture and Fixtures [Member]
Property, Plant, and Equipment, Gross	1,968	1,947
Computer Equipment [Member]
Property, Plant, and Equipment, Gross	5,233	5,223
Construction in Progress [Member]
Property, Plant, and Equipment, Gross	$ 540	$ 421