Segment and Related Information - Financial Information by Industry Segment (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 28, 2013	Sep. 28, 2013	Jun. 29, 2013	Mar. 30, 2013	Dec. 29, 2012	Sep. 29, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 28, 2013	Dec. 29, 2012	Dec. 31, 2011
Net sales by segment:
Total consolidated net sales and net sales for reportable segments	$ 64,670	$ 59,962	$ 66,652	$ 56,016	$ 50,714	$ 57,748	$ 59,404	$ 53,296	$ 247,300	$ 221,162	$ 308,968
Segment profit (loss):
Profit (loss) for reportable segments									(35,800)	(14,084)	17,336
Other unallocated amounts:
Corporate expenses									(5,977)	(7,785)	(5,021)
Interest and other income									54	967	442
Income (loss) before income taxes									(35,746)	(13,117)	17,778
Depreciation and amortization by segment deducted in arriving at profit (loss):
Total Depreciation expense									5,387	5,346	5,422
Intangible amortization									8,082	4,057	4,645
Total depreciation and amortization for reportable segments									13,469	9,403	10,067
Capital expenditures by segment:
Total consolidated capital expenditures									3,908	3,267	1,413
Total assets by segment:
Total consolidated assets	345,423				334,873				345,423	334,873	361,608
Operating Segments [Member]
Segment profit (loss):
Profit (loss) for reportable segments									(29,823)	(6,299)	22,357
Total assets by segment:
Total consolidated assets	328,201				313,232				328,201	313,232	288,755
Corporate, Non-Segment [Member]
Total assets by segment:
Corporate, principally cash and investments and deferred taxes	17,222				21,641				17,222	21,641	72,853
Semiconductor Equipment [Member]
Depreciation and amortization by segment deducted in arriving at profit (loss):
Total Depreciation expense									4,723	4,506	4,313
Capital expenditures by segment:
Total consolidated capital expenditures									3,607	2,759	991
Semiconductor Equipment [Member] | Operating Segments [Member]
Net sales by segment:
Total consolidated net sales and net sales for reportable segments									214,511	179,449	260,648
Segment profit (loss):
Profit (loss) for reportable segments									(24,998)	(5,331)	20,040
Total assets by segment:
Total consolidated assets	297,175				281,173				297,175	281,173	255,189
Microwave Communications [Member]
Depreciation and amortization by segment deducted in arriving at profit (loss):
Total Depreciation expense									523	652	893
Capital expenditures by segment:
Total consolidated capital expenditures									267	481	313
Microwave Communications [Member] | Operating Segments [Member]
Net sales by segment:
Total consolidated net sales and net sales for reportable segments									17,063	26,863	29,967
Segment profit (loss):
Profit (loss) for reportable segments									(6,142)	(847)	1,510
Total assets by segment:
Total consolidated assets	22,156				22,635				22,156	22,635	21,968
Video Cameras [Member]
Depreciation and amortization by segment deducted in arriving at profit (loss):
Total Depreciation expense									141	188	216
Capital expenditures by segment:
Total consolidated capital expenditures									34	27	109
Video Cameras [Member] | Operating Segments [Member]
Net sales by segment:
Total consolidated net sales and net sales for reportable segments									15,726	14,850	18,353
Segment profit (loss):
Profit (loss) for reportable segments									1,317	(121)	807
Total assets by segment:
Total consolidated assets	$ 8,870				$ 9,424				$ 8,870	$ 9,424	$ 11,598