Condensed Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Income Statement [Abstract]
Net sales	$ 59,962	$ 57,748	$ 182,630	$ 170,448
Cost and expenses:
Cost of sales	45,441	39,622	131,052	119,119
Research and development	11,636	9,136	36,814	26,194
Selling, general and administrative	14,845	11,597	44,098	33,514
Total cost and expenses	71,922	60,355	211,964	178,827
Loss from operations	(11,960)	(2,607)	(29,334)	(8,379)
Interest and other, net	16	739	42	920
Loss before income taxes	(11,944)	(1,868)	(29,292)	(7,459)
Income tax benefit	(1,124)	(119)	(2,324)	(377)
Net loss	$ (10,820)	$ (1,749)	$ (26,968)	$ (7,082)
Loss per share:
Basic	$ (0.43)	$ (0.07)	$ (1.09)	$ (0.29)
Diluted	$ (0.43)	$ (0.07)	$ (1.09)	$ (0.29)
Weighted average shares used in computing loss per share:
Basic	24,929	24,479	24,801	24,421
Diluted	24,929	24,479	24,801	24,421
Cash dividends declared per share	$ 0.06	$ 0.06	$ 0.18	$ 0.18