Industry Segments - Financial Information by Industry Segment (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Net sales by segment:
Total consolidated net sales and net sales for reportable segments	$ 59,962	$ 57,748	$ 182,630	$ 170,448
Segment profit (loss):
Loss for reportable segments	(11,960)	(2,607)	(29,334)	(8,379)
Other unallocated amounts:
Corporate expenses	(1,516)	(1,787)	(5,069)	(5,175)
Interest and other, net	16	739	42	920
Loss before income taxes	(11,944)	(1,868)	(29,292)	(7,459)
Operating Segments [Member]
Segment profit (loss):
Loss for reportable segments	(10,444)	(820)	(24,265)	(3,204)
Operating Segments [Member] | Semiconductor Equipment [Member]
Net sales by segment:
Total consolidated net sales and net sales for reportable segments	52,403	47,002	160,326	139,279
Segment profit (loss):
Loss for reportable segments	(9,391)	(1,006)	(18,857)	(2,345)
Operating Segments [Member] | Microwave Communications [Member]
Net sales by segment:
Total consolidated net sales and net sales for reportable segments	3,574	7,051	10,112	19,663
Segment profit (loss):
Loss for reportable segments	(1,511)	53	(6,524)	(810)
Operating Segments [Member] | Video Cameras [Member]
Net sales by segment:
Total consolidated net sales and net sales for reportable segments	3,985	3,695	12,192	11,506
Segment profit (loss):
Loss for reportable segments	$ 458	$ 133	$ 1,116	$ (49)