Note 6 - Discontinued Operations - Summary of Operating Results (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 24, 2017	Jun. 25, 2016	Jun. 24, 2017	Jun. 25, 2016
Loss, net of tax	$ (278)	$ (55)	$ (278)	$ (55)
Broadcast Microwave Services, Inc. (“BMS”) [Member]
Net sales
Operating loss before income taxes
Gain (loss) from disposal of segment	(278)	(55)	(278)	(55)
Loss before taxes	(278)	(55)	(278)	(55)
Income tax provision
Loss, net of tax	$ (278)	$ (55)	$ (278)	$ (55)

Amount before tax of gain (loss) not previously recognized resulting from the disposal of a discontinued operation.

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