Schedule of Segment Reporting Information by Segment Charges (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 28, 2014	Sep. 29, 2013	Sep. 28, 2014	Sep. 29, 2013
Segment Reporting Information [Line Items]
Restructuring and other	$ (405)	$ 889	$ 167	$ 1,480
Semiconductor Test
Segment Reporting Information [Line Items]
Cost of revenues-provision for excess and obsolete inventory	4,404	1,378	14,322	1,878
Restructuring and other		282		416
Total	4,404	1,660	14,322	2,294
System Test
Segment Reporting Information [Line Items]
Cost of revenues-provision for excess and obsolete inventory	763	404	1,944	1,613
Restructuring and other	225	1,055	371	1,430
Total	988	1,459	2,315	3,043
Wireless Test
Segment Reporting Information [Line Items]
Cost of revenues-provision for excess and obsolete inventory	1,267	2,059	5,239	6,125
Restructuring and other			426	82
Total	1,267	2,059	5,665	6,207
Corporate And Eliminations
Segment Reporting Information [Line Items]
Restructuring and other	(630)	(448)	(630)	(448)
Total	$ (630)	$ (448)	$ (630)	$ (448)