Condensed Consolidated Statements of Income (Unaudited) (USD $) In Thousands, except Per Share data	3 Months Ended		6 Months Ended
	Jun. 25, 2011	Jun. 26, 2010	Jun. 25, 2011	Jun. 26, 2010
Condensed Consolidated Statements of Income [Abstract]
Net sales	$ 80,896	$ 74,869	$ 170,596	$ 139,699
Cost and expenses:
Cost of sales	54,349	47,441	115,234	92,272
Research and development	9,284	9,012	18,367	17,661
Selling, general and administrative	11,434	9,489	23,524	19,368
Total cost and expenses	75,067	65,942	157,125	129,301
Income from operations	5,829	8,927	13,471	10,398
Interest and other, net	116	138	226	312
Income before income taxes	5,945	9,065	13,697	10,710
Income tax provision	895	2,367	2,073	3,105
Net income	$ 5,050	$ 6,698	$ 11,624	$ 7,605
Income per share:
Basic	$ 0.21	$ 0.28	$ 0.48	$ 0.32
Diluted	$ 0.21	$ 0.28	$ 0.47	$ 0.32
Weighted average shares used in computing income per share:
Basic	24,103	23,657	24,060	23,603
Diluted	24,484	24,086	24,483	23,978
Cash dividends declared per share	$ 0.06	$ 0.06	$ 0.12	$ 0.12