Schedule of Segment Reporting Information by Segment Charges (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Oct. 02, 2011	Sep. 30, 2012	Oct. 02, 2011
Semiconductor Test
Segment Reporting Information
Cost of revenues-provision for excess and obsolete inventory	$ 3,085	$ 4,202	$ 9,254	$ 10,144
Restructuring and other, net	(4)	137	315	2,307
Total	3,081	4,339	9,569	12,451
Systems Test Group
Segment Reporting Information
Cost of revenues-provision for excess and obsolete inventory	378	211	3,020	612
Restructuring and other, net	451		451	(246)
Total	829	211	3,471	366
Wireless Test
Segment Reporting Information
Cost of revenues-inventory step-up			6,089
Cost of revenues-provision for excess and obsolete inventory	2,018		4,134
Restructuring and other, net	236		236
Total	2,254		10,459
Corporate And Eliminations
Segment Reporting Information
Restructuring and other, net		1,328	(8,406)	1,096
Total		$ 1,328	$ (8,406)	$ 1,096