Condensed Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 28, 2015	Mar. 29, 2014
Income Statement [Abstract]
Net sales	$ 68,068	$ 64,864
Cost and expenses:
Cost of sales	46,309	42,664
Research and development	9,629	10,560
Selling, general and administrative	13,835	15,063
Total cost and expenses	69,773	68,287
Loss from operations	(1,705)	(3,423)
Interest and other, net	6	15
Loss from continuing operations before taxes	(1,699)	(3,408)
Income tax provision (benefit)	1,041	(56)
Loss from continuing operations	(2,740)	(3,352)
Income from discontinued operations, net of tax (Note 2)		5
Net loss	$ (2,740)	$ (3,347)
Basic:
Loss from continuing operations	$ (0.11)	$ (0.13)
Income from discontinued operations, net of tax		$ 0.00
Net loss	$ (0.11)	$ (0.13)
Diluted:
Loss from continuing operations	$ (0.11)	$ (0.13)
Income from discontinued operations, net of tax		$ 0.00
Net loss	$ (0.11)	$ (0.13)
Weighted average shares used in computing income (loss) per share:
Basic	25,751	25,123
Diluted	25,751	25,123
Cash dividends declared per share	$ 0.06	$ 0.06