Basic And Diluted Net Income Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jul. 02, 2011	Jun. 30, 2012	Jul. 02, 2011
Numerator:
Net income	$ 11,171	$ 9,728	$ 21,371	$ 17,595
Denominator:
Basic weighted-average shares outstanding (in shares)	26,530,000	25,731,000	26,387,000	25,488,000
Effect of dilutive employee stock options and restricted stock units (in shares)	857,000	1,157,000	860,000	1,073,000
Diluted weighted-average shares outstanding (in shares)	27,387,000	26,888,000	27,247,000	26,561,000
Net income per share - basic:
Net income per share - basic (in dollars per share)	$ 0.42	$ 0.38	$ 0.81	$ 0.69
Net income per share - diluted:
Net income per share - diluted (in dollars per share)	$ 0.41	$ 0.36	$ 0.78	$ 0.66
Common Stock
Net income per share - diluted:
Antidilutive securities excluded from computation of earnings per share (in shares)	1,300,000	600,000	1,300,000	700,000
Restricted Stock Units (RSUs)
Net income per share - diluted:
Antidilutive securities excluded from computation of earnings per share (in shares)	100,000	100,000	100,000	0