Industry Segments - Financial Information by Industry Segment (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 29, 2013	Jun. 30, 2012	Jun. 29, 2013	Jun. 30, 2012
Net sales by segment:
Total consolidated net sales and net sales for reportable segments	$ 66,652	$ 59,404	$ 122,668	$ 112,700
Segment profit (loss):
Loss for reportable segments	(4,445)	(2,065)	(17,374)	(5,772)
Other unallocated amounts:
Corporate expenses	(1,650)	(1,899)	(3,553)	(3,388)
Interest and other, net	16	89	26	181
Loss before income taxes	(4,429)	(1,976)	(17,348)	(5,591)
Operating Segments [Member]
Segment profit (loss):
Loss for reportable segments	(2,795)	(166)	(13,821)	(2,384)
Operating Segments [Member] | Semiconductor equipment [Member]
Net sales by segment:
Total consolidated net sales and net sales for reportable segments	59,339	48,604	107,923	92,277
Segment profit (loss):
Loss for reportable segments	(605)	368	(9,466)	(1,339)
Operating Segments [Member] | Microwave communications [Member]
Net sales by segment:
Total consolidated net sales and net sales for reportable segments	2,895	5,834	6,538	12,612
Segment profit (loss):
Loss for reportable segments	(2,641)	(988)	(5,013)	(863)
Operating Segments [Member] | Video cameras [Member]
Net sales by segment:
Total consolidated net sales and net sales for reportable segments	4,418	4,966	8,207	7,811
Segment profit (loss):
Loss for reportable segments	$ 451	$ 454	$ 658	$ (182)