Note 14 - Segment Information - Total Assets by Geographic Area (Details) - USD ($) $ in Thousands	Mar. 28, 2020	Dec. 28, 2019	Mar. 30, 2019
Total assets	$ 83,951	$ 96,173	$ 92,811
UNITED STATES
Total assets	63,470	75,724
CANADA
Total assets	13,498	13,770
PUERTO RICO
Total assets	1,931	2,066
SERBIA
Total assets	$ 5,052	$ 4,613