Statements of Operations (Parenthetical) (Detail) (USD $)	3 Months Ended									12 Months Ended		3 Months Ended								3 Months Ended
	Sep. 30, 2012 Employee	Dec. 31, 2011		Sep. 30, 2011		Jun. 30, 2011		Mar. 31, 2011		Dec. 31, 2012	Dec. 31, 2011	Jun. 30, 2012 Semiconductor Test Employee	Jun. 30, 2011 Semiconductor Test Employee	Mar. 31, 2011 Semiconductor Test Employee	Dec. 31, 2011 Litepoint Corporation	Sep. 30, 2011 Litepoint Corporation	Dec. 31, 2012 Litepoint Corporation	Jun. 30, 2012 Litepoint Corporation	Mar. 31, 2012 Litepoint Corporation	Sep. 30, 2012 Systems Test Group Employee	Sep. 30, 2012 Wireless Test Employee
Quarterly Financial Information [Line Items]
Pension settlement charges																	$ (400,000)	$ (6,500,000)	$ (1,800,000)
Severance benefit and charges	700,000									200,000		300,000	300,000	800,000						500,000	200,000
Reduction in employees headcount	9											10	2	5						7	2
Gain on disposal of discontinued operations, tax		4,578,000	[1],[2]	4,578,000	[3]	4,578,000	[4]	4,578,000	[5]		4,578,000
Early exit of leased facility														(400,000)
Pension settlement charges													700,000		3,300,000
Acquisition charges															$ 500,000	$ 1,400,000

[1] Restructuring and other, net includes $0.5 million of charges related to pension settlement and $3.3 million to the acquisition of LitePoint.

[2] In the fourth quarter ended December 31, 2011, the change in recognizing pension and postretirement benefit plans expense, as a result of the mark-to-market adjustments, decreased gross profit and net income by $2.4 million and $6.1 million, respectively. See Note B: "Accounting Policies" for a discussion of our accounting policy.

[3] Restructuring and other, net includes $1.4 million of charges related to the acquisition of LitePoint.

[4] Restructuring and other, net includes $0.3 million of severance charges related to headcount reductions of approximately 2 people in Semiconductor Test and $0.7 million related to pension settlement charges.

[5] Restructuring and other, net includes $0.8 million of severance charges related to headcount reductions of approximately 5 people in Semiconductor Test and $(0.4) million credit related to early exit of previously impaired leased facilities in Westford and North Reading, Massachusetts.