CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 28, 2014	Jun. 29, 2013	Jun. 28, 2014	Jun. 29, 2013
Income Statement [Abstract]
Net sales	$ 77,850	$ 62,234	$ 142,714	$ 114,461
Cost and expenses:
Cost of sales	52,366	42,720	95,030	81,005
Research and development	10,180	11,192	20,740	24,065
Selling, general and administrative	14,259	13,218	29,323	27,423
Total cost and expenses	76,805	67,130	145,093	132,493
Income (loss) from operations	1,045	(4,896)	(2,379)	(18,032)
Interest and other, net	5	16	19	26
Income (loss) from continuing operations before taxes	1,050	(4,880)	(2,360)	(18,006)
Income tax provision (benefit)	119	(546)	63	(1,437)
Income (loss) from continuing operations	931	(4,334)	(2,423)	(16,569)
Income from discontinued operations, net of tax (Note 2)	3,232	289	3,238	421
Net income (loss)	$ 4,163	$ (4,045)	$ 815	$ (16,148)
Basic:
Income (loss) from continuing operations	$ 0.04	$ (0.17)	$ (0.10)	$ (0.67)
Income from discontinued operations, net of tax	$ 0.12	$ 0.01	$ 0.13	$ 0.02
Net income (loss)	$ 0.16	$ (0.16)	$ 0.03	$ (0.65)
Diluted:
Income (loss) from continuing operations	$ 0.04	$ (0.17)	$ (0.10)	$ (0.67)
Income from discontinued operations, net of tax	$ 0.12	$ 0.01	$ 0.13	$ 0.02
Net income (loss)	$ 0.16	$ (0.16)	$ 0.03	$ (0.65)
Weighted average shares used in computing Income (loss) per share:
Basic	25,324	24,817	25,223	24,737
Diluted	25,797	24,817	25,223	24,737
Cash dividends declared per share	$ 0.06	$ 0.06	$ 0.12	$ 0.12