Acquisitions (Details) (Contingent compensation expense [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 30, 2014	Mar. 31, 2013
Business Combination, Separately Recognized Transactions [Line Items]
Contingent compensation expense	$ 2,839	$ 3,418
Research and Development Expense [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Contingent compensation expense	83	489
Selling, general and administrative [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Contingent compensation expense	$ 2,756	$ 2,929

The expenses and losses recorded for each transaction with the acquiree that was recognized separately from the acquisition of assets and assumptions of liabilities in the business combination.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (e)(3)

-URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1392-128463

Name:	us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsExpensesAndLossesRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration