Stock-Based Compensation Expense (Details 1) (USD $)	3 Months Ended		6 Months Ended
	Jul. 01, 2012	Jul. 03, 2011	Jul. 01, 2012	Jul. 03, 2011
Employee Stock Option [Member]
Weighted average assumptions in fair value of option grant
Estimated grant date fair value per share	$ 2.64	$ 2.65	$ 2.86	$ 2.14
Expected life (years)	4 years 6 months 7 days	5 years 4 days	4 years 5 months 16 days	4 years 6 months 4 days
Risk-free interest rate	1.00%	2.00%	1.00%	2.00%
Volatility	49.00%	47.00%	47.00%	47.00%
Employee Stock Purchase Plan [Member]
Weighted average assumptions in fair value of option grant
Estimated grant date fair value per share	$ 2.19	$ 2.10
Expected life (years)	9 months 18 days	9 months 18 days
Risk-free interest rate	0.17%	0.02%
Volatility	41.00%	37.00%