Industry Segment (Financial Information by Industry Segment) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 29, 2012	Sep. 24, 2011	Sep. 29, 2012	Sep. 24, 2011
Net sales by segment:
Total consolidated net sales and net sales for reportable segments	$ 57,748	$ 71,813	$ 170,448	$ 242,409
Segment profit (loss):
Profit (loss) for reportable segments	(820)	3,840	(3,204)	19,859
Other unallocated amounts:
Corporate expenses	(1,787)	(1,180)	(5,175)	(3,728)
Interest and other, net	739	114	920	340
Income (loss) before income taxes	(1,868)	2,774	(7,459)	16,471
Semiconductor Equipment [Member]
Net sales by segment:
Total consolidated net sales and net sales for reportable segments	47,002	59,409	139,279	208,480
Segment profit (loss):
Profit (loss) for reportable segments	(1,006)	3,274	(2,345)	19,480
Microwave Communications [Member]
Net sales by segment:
Total consolidated net sales and net sales for reportable segments	7,051	7,672	19,663	20,620
Segment profit (loss):
Profit (loss) for reportable segments	53	371	(810)	(89)
Video cameras [Member]
Net sales by segment:
Total consolidated net sales and net sales for reportable segments	3,695	4,732	11,506	13,309
Segment profit (loss):
Profit (loss) for reportable segments	$ 133	$ 195	$ (49)	$ 468