Accounting Policies (Narrative) (Details) (USD $)	12 Months Ended
	Jan. 02, 2015	Jan. 03, 2014	Dec. 28, 2012
Accounting Policies [Line Items]
Advertising expense	$ 39,000,000	$ 33,800,000	$ 32,900,000
Research and Development expense with third party funding earned	13,500,000	5,100,000	3,500,000
Depreciation expense	$ 33,129,000	$ 26,736,000	$ 23,691,000
Maturity period of derivative financial instrument, minimum, in months	1 month
Maturity period of derivative financial instrument, maximum, in months	3 months
Building [Member]
Accounting Policies [Line Items]
Useful life of asset, in years	39 years
Leasehold Improvements [Member]
Accounting Policies [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	the life of the lease
Minimum [Member]
Accounting Policies [Line Items]
Estimated useful lives goodwill and purchased intangible assets, in years	1 month
Warranty periods for products sold	90 days
Restricted stock units to be vest, in years	4 years
Minimum [Member] | Machinery And Equipment [Member]
Accounting Policies [Line Items]
Useful life of asset, in years	4 years
Minimum [Member] | Furniture And Fixtures [Member]
Accounting Policies [Line Items]
Useful life of asset, in years	5 years
Minimum [Member] | Computer Equipment And Software [Member]
Accounting Policies [Line Items]
Useful life of asset, in years	2 years
Minimum [Member] | Internal-Use Of Software [Member]
Accounting Policies [Line Items]
Useful life of asset, in years	2 years
Maximum [Member]
Accounting Policies [Line Items]
Estimated useful lives goodwill and purchased intangible assets, in years	12 years
Warranty periods for products sold	5 years 6 months
Restricted stock units to be vest, in years	5 years
Maximum [Member] | Machinery And Equipment [Member]
Accounting Policies [Line Items]
Useful life of asset, in years	6 years
Maximum [Member] | Furniture And Fixtures [Member]
Accounting Policies [Line Items]
Useful life of asset, in years	7 years
Maximum [Member] | Computer Equipment And Software [Member]
Accounting Policies [Line Items]
Useful life of asset, in years	5 years
Maximum [Member] | Internal-Use Of Software [Member]
Accounting Policies [Line Items]
Useful life of asset, in years	5 years
Weighted Average [Member]
Accounting Policies [Line Items]
Estimated useful lives goodwill and purchased intangible assets, in years	6 years 3 months 26 days