Segment and Related Information - Net Assets by Product Line (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 29, 2012	Dec. 31, 2011	Dec. 25, 2010
Total assets by segment:
Corporate, principally cash and investments and deferred taxes	$ 21,641	$ 72,853	$ 71,893
Total consolidated assets	334,873	361,608	366,043
Total assets for reportable segments [Member]
Total assets by segment:
Total consolidated assets	313,232	288,755	294,150
Semiconductor equipment [Member]
Total assets by segment:
Total consolidated assets	281,173	255,189	255,246
Microwave communications [Member]
Total assets by segment:
Total consolidated assets	22,635	21,968	27,812
Video cameras [Member]
Total assets by segment:
Total consolidated assets	$ 9,424	$ 11,598	$ 11,092