Net Income Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 28, 2013	Jun. 29, 2012	Jun. 28, 2013	Jun. 29, 2012
Earnings Per Share, Diluted, Other Disclosures [Abstract]
Weighted-average number of shares outstanding during period	15,459	15,123	15,445	15,147
Common stock equivalents - incremental shares primarily under stock option plans	1,639	1,624	1,637	1,663
Number of shares on which diluted earnings per share is based	17,098	16,747	17,082	16,810
Net income	$ 4,055	$ 4,123	$ 8,112	$ 7,483
Earnings per share, basic (in dollars per share)	$ 0.26	$ 0.27	$ 0.53	$ 0.49
Earnings per share, diluted (in dollars per share)	$ 0.24	$ 0.25	$ 0.47	$ 0.45