Industry Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 25, 2011	Jun. 30, 2012	Jun. 25, 2011
Net sales by segment:
Total consolidated net sales and net reportable segments	$ 59,404	$ 80,896	$ 112,700	$ 170,596
Segment profit (loss):
Profit (loss) for reporting segments	(166)	7,205	(2,384)	16,019
Other unallocated amounts:
Corporate expenses	(1,899)	(1,376)	(3,388)	(2,548)
Interest and other, net	89	116	181	226
Income (loss) before income taxes	(1,976)	5,945	(5,591)	13,697
Semiconductor Equipment [Member]
Net sales by segment:
Total consolidated net sales and net reportable segments	48,604	69,628	92,277	149,071
Segment profit (loss):
Profit (loss) for reporting segments	368	7,218	(1,339)	16,206
Microwave Communications [Member]
Net sales by segment:
Total consolidated net sales and net reportable segments	5,834	5,932	12,612	12,948
Segment profit (loss):
Profit (loss) for reporting segments	(988)	(469)	(863)	(460)
Video Cameras [Member]
Net sales by segment:
Total consolidated net sales and net reportable segments	4,966	5,336	7,811	8,577
Segment profit (loss):
Profit (loss) for reporting segments	$ 454	$ 456	$ (182)	$ 273