v2.4.0.8
Summary of Significant Accounting Policies - Fair Value Hierarchy for Financial Assets (Detail) (Recurring, USD $)
In Thousands, unless otherwise specified
Dec. 28, 2013
Dec. 29, 2012
Fair value hierarchy for financial assets    
Total $ 27,790 $ 33,622
U.S. Treasuries
    
Fair value hierarchy for financial assets    
Total 25,997 31,999
Money Market funds
    
Fair value hierarchy for financial assets    
Total 1,793 1,623
Level 1
    
Fair value hierarchy for financial assets    
Total 27,790 33,622
Level 1 | U.S. Treasuries
    
Fair value hierarchy for financial assets    
Total 25,997 31,999
Level 1 | Money Market funds
    
Fair value hierarchy for financial assets    
Total 1,793 1,623
Level 2
    
Fair value hierarchy for financial assets    
Total 0 0
Level 2 | U.S. Treasuries
    
Fair value hierarchy for financial assets    
Total 0 0
Level 2 | Money Market funds
    
Fair value hierarchy for financial assets    
Total 0 0
Level 3
    
Fair value hierarchy for financial assets    
Total 0 0
Level 3 | U.S. Treasuries
    
Fair value hierarchy for financial assets    
Total 0 0
Level 3 | Money Market funds
    
Fair value hierarchy for financial assets    
Total $ 0 $ 0