Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 28, 2013	Dec. 29, 2012	Dec. 31, 2011
Income Statement [Abstract]
Net sales	$ 247,300	$ 221,162	$ 308,968
Cost and expenses:
Cost of sales	176,774	153,184	208,839
Research and development	48,596	36,171	36,230
Selling, general and administrative	57,730	45,891	46,563
Total cost and expenses	283,100	235,246	291,632
Income (loss) from operations	(35,800)	(14,084)	17,336
Interest and other income	54	967	442
Income (loss) before income taxes	(35,746)	(13,117)	17,778
Income tax provision (benefit)	(2,328)	(874)	2,059
Net income (loss)	$ (33,418)	$ (12,243)	$ 15,719
Income (loss) per share:
Basic	$ (1.34)	$ (0.50)	$ 0.65
Diluted	$ (1.34)	$ (0.50)	$ 0.64
Weighted average shares used in computing income (loss) per share:
Basic	24,859	24,459	24,134
Diluted	24,859	24,459	24,501