Geographic And Group Information (Geographic Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 02, 2015	Sep. 26, 2014	Oct. 02, 2015	Sep. 26, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 67,217	$ 60,437	$ 194,586	$ 176,394
North America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	57,060	48,094	161,025	142,797
International Primarily European Countries [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 10,157	$ 12,343	$ 33,561	$ 33,597