Note 1 - Summary of Significant Accounting Policies - Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 30, 2017
Property, plant and equipment	$ 68,614	$ 67,129
Less accumulated depreciation and amortization	(33,492)	(32,957)
Property, plant and equipment, net	35,122	34,172	[1]
Land and Land Improvements [Member]
Property, plant and equipment	8,331	8,017
Building and Building Improvements [Member]
Property, plant and equipment	14,265	13,779
Machinery and Equipment [Member]
Property, plant and equipment	$ 46,018	$ 45,333

[1] Derived from December 30, 2017 audited financial statements