Share-Based Compensation (Details 1) (USD $)	3 Months Ended
Apr. 01, 2012 year	Apr. 03, 2011 year
Option Plan Shares [Member]
Fair value of stock options granted to employees, officers and non-employee board members and ESPP shares granted to employees
Dividend yield	0.00%	0.00%
Expected volatility	43.00%	43.00%
Risk-free interest rate	0.62%	1.72%
Expected term (in years)	4.3	4.3
Estimated annual forfeiture rate	8.57%	7.32%
Weighted average fair value at grant date	$ 17.09	$ 17.94
Employee Stock Purchase Plan Shares [Member]
Fair value of stock options granted to employees, officers and non-employee board members and ESPP shares granted to employees
Dividend yield	0.00%	0.00%
Expected volatility	38.00%	43.00%
Risk-free interest rate	0.15%	0.17%
Expected term (in years)	0.5	0.5
Weighted average fair value at grant date	$ 12.24	$ 13.79

The period of time an equity-based award is expected to be outstanding. An equity-based award's expected term is generally determined based on, among other factors, the instrument's contractual term and the effects of employees' expected exercise and post-vesting employment termination behavior.

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The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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