Schedule of Segment Reporting Information by Segment Charges (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Segment Reporting Information [Line Items]
Restructuring and other, net			$ 5,800
Semiconductor Test
Segment Reporting Information [Line Items]
Cost of revenues-inventory charge	18,433	[1]	10,370	[1]	4,521	[1]
Restructuring and other, net	386		2,142		1,437
Systems Test Group
Segment Reporting Information [Line Items]
Cost of revenues-inventory charge	4,271		1,090		1,450
Restructuring and other, net	451		(300)		(2,133)
Wireless Test
Segment Reporting Information [Line Items]
Cost of revenues-inventory step-up	6,089	[2]	12,178	[2]
Cost of revenues-inventory charge	4,145		141
Restructuring and other, net	236
Corporate And Eliminations
Segment Reporting Information [Line Items]
Restructuring and other, net	$ (8,794)		$ 4,901		$ (3,104)

[1] Included in the cost of revenues for the years ended December 31, 2012 and 2011 are charges for excess inventory provisions recorded primarily as a result of product transition.

[2] Included in the cost of revenues for the years ended December 31, 2012 and 2011 is the cost for purchase accounting inventory step-up.