Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Income Statement [Abstract]
Net sales	$ 333,323	$ 231,574	$ 206,312
Cost and expenses:
Cost of sales	221,088	168,186	144,590
Research and development	40,601	46,452	33,564
Selling, general and administrative	57,536	54,053	42,121
Impairment of goodwill and other assets (Note 3)	5,000
Total cost and expenses	324,225	268,691	220,275
Income (loss) from operations	9,098	(37,117)	(13,963)
Interest and other from continuing operations, net	30	54	967
Income (loss) from continuing operations before taxes	9,128	(37,063)	(12,996)
Income tax provision (benefit)	3,293	(2,803)	(874)
Income (loss) from continuing operations	5,835	(34,260)	(12,122)
Income (loss) from discontinued operations, net of tax	2,873	842	(121)
Net income (loss)	$ 8,708	$ (33,418)	$ (12,243)
Basic:
Income (loss) from continuing operations	$ 0.23	$ (1.37)	$ (0.50)
Income from discontinued operations, net of tax	$ 0.11	$ 0.03	$ 0.00
Net income (loss)	$ 0.34	$ (1.34)	$ (0.50)
Diluted:
Income (loss) from continuing operations	$ 0.22	$ (1.37)	$ (0.50)
Income from discontinued operations, net of tax	$ 0.11	$ 0.03	$ 0.00
Net income (loss)	$ 0.33	$ (1.34)	$ (0.50)
Weighted average shares used in computing income (loss) per share:
Basic	25,393	24,859	24,459
Diluted	26,006	24,859	24,459