Restructuring (Details) - USD ($)	6 Months Ended
	Jun. 25, 2016	Jun. 27, 2015
Restructuring Reserve [Roll Forward]
Beginning Balance	$ 256,000	$ 997,000
Charges	0	58,000
Cash Payments	(229,000)	(631,000)
Ending Balance	27,000	424,000
Employee severance and benefits [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance	0	383,000
Charges	0	45,000
Cash Payments	0	(428,000)
Ending Balance	0	0
Facility termination costs [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance	249,000	583,000
Charges	0	0
Cash Payments	(229,000)	(168,000)
Ending Balance	20,000	415,000
Other [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance	7,000	31,000
Charges	0	13,000
Cash Payments	0	(35,000)
Ending Balance	$ 7,000	$ 9,000