Acquisitions Additional information (Details) (USD $)	3 Months Ended				9 Months Ended
	Sep. 28, 2013	Jun. 29, 2013	Sep. 29, 2012	Jun. 30, 2012	Sep. 28, 2013	Sep. 29, 2012	Apr. 01, 2013	Apr. 02, 2012	Dec. 31, 2011
Acquisitions [Abstract]
Acquired Intangible assets, Weighted Average Useful Life		10 years
Cash paid at closing		$ 13,358,000			$ 13,358,000	$ 2,961,000
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High							14,500,000
Equity Method Investment, Ownership Percentage									50.00%
Business Acquisition, Percentage of Voting Interests Acquired								50.00%
Business Combination, Step Acquisition, Equity Interest in Acquiree, Fair Value				2,900,000
Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain				1,300,000
Goodwill							10,090,000	1,900,000
Foreign currency transaction gain realized upon acquisition				200,000
Total purchase price				3,400,000
Contingent consideration obligation							3,094,000
Contingent consideration fair value adjustment	$ (1,813,000)		$ 0		$ (1,813,000)	$ 0