Fair Value of Financial Instruments (Details) (USD $) In Thousands, unless otherwise specified	Dec. 28, 2013	Dec. 29, 2012
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of marketable securities	$ 106,746	$ 69,582
Level 1
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total fair value of financial instruments	101,505	64,865
Level 1 | Short Term
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of marketable securities	101,505	64,865
Level 2
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Foreign currency forward exchange contracts	48	(5)
Total fair value of financial instruments	48	(5)
Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total fair value of financial instruments	5,241	4,717
Level 3 | Long Term
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of marketable securities	5,241	4,717
Total
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Foreign currency forward exchange contracts	48	(5)
Total fair value of financial instruments	106,794	69,577
Total | Short Term
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of marketable securities	101,505	64,865
Total | Long Term
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of marketable securities	$ 5,241	$ 4,717