Note 2 - Discontinued Operations - Summary of Operating Results (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 24, 2016	Sep. 26, 2015	Sep. 24, 2016	Sep. 26, 2015
Broadcast Microwave Services, Inc. (“BMS”) [Member]
Net sales				$ 6,965
Operating loss before income taxes				(1,963)
Gain (loss) from sale of BMS	51	(222)	(4)	(3,232)
Income (loss) before taxes	51	(222)	(4)	(5,195)
Income tax provision				6
Income (loss), net of tax	51	(222)	(4)	(5,201)
Income (loss), net of tax	$ 51	$ (222)	$ (4)	$ (5,201)