Note 14 - Segment Information - Revenues by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 28, 2020	Mar. 30, 2019
Revenues	$ 45,033	$ 51,595
UNITED STATES
Revenues	39,176	45,302
CANADA
Revenues	4,002	4,588
PUERTO RICO
Revenues	1,202	1,203
SERBIA
Revenues	$ 653	$ 502