Stock-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jul. 04, 2015	Jun. 28, 2014	Jul. 04, 2015	Jun. 28, 2014
Stock-based compensation costs
Share based compensation cost before tax	$ 11,057	$ 9,282	$ 21,576	$ 18,559
Income tax benefit	1,182	587	2,486	1,898
Share based compensation cost after tax	9,875	8,695	19,090	16,661
Total unrecognized compensation costs related to awards	66,200		$ 66,200
Weighted-average period of recognition of unrecognized compensation costs			2 years 2 months 12 days
Cost of revenues
Stock-based compensation costs
Share based compensation cost before tax	229	178	$ 459	374
Research and development
Stock-based compensation costs
Share based compensation cost before tax	4,960	4,327	9,755	8,568
Selling, general and administrative
Stock-based compensation costs
Share based compensation cost before tax	$ 5,868	$ 4,777	$ 11,362	$ 9,617

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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The amount of expense, net of income tax, recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Unrecognized cost of unvested share-based compensation awards.

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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

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