Goodwill and Acquired Intangibles (Details 2) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2015	Jun. 28, 2014	Jul. 04, 2015	Jun. 28, 2014
Amortization of acquired intangibles
Cost of product and maintenance	$ 10,105	$ 8,613	$ 20,278	$ 16,189
Amortization of acquired intangibles	6,119	5,579	12,350	10,789
Total amortization of acquired intangibles	$ 16,224	$ 14,192	$ 32,628	$ 26,978