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Stock-Based Compensation - Summary of Weighted-Average Assumptions in Fair Value of Option Grant (Detail) (USD $)
3 Months Ended 6 Months Ended
Jun. 30, 2013
Jul. 01, 2012
Jun. 30, 2013
Jul. 01, 2012
Stock Options [Member]
       
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Estimated grant date fair value per share $ 2.29 $ 2.64 $ 2.33 $ 2.86
Expected life (years) 4 years 5 months 19 days 4 years 6 months 7 days 4 years 4 months 17 days 4 years 5 months 16 days
Risk-free interest rate 1.00% 1.00% 1.00% 1.00%
Volatility 47.00% 49.00% 49.00% 47.00%
Employee Stock Purchase Plan [Member]
       
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Estimated grant date fair value per share $ 1.88 $ 2.19    
Expected life (years) 9 months 18 days 9 months 18 days    
Risk-free interest rate 0.11% 0.17%    
Volatility 34.00% 41.00%