Summary of Charges Related to Accrued Restructuring Activity (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Jan. 31, 2011	Jul. 31, 2013		Jul. 31, 2012		Jul. 31, 2011
Restructuring Cost and Reserve [Line Items]
Balance at beginning period		$ 277	[1]	$ 5,190	[1]	$ 875	[1]
Restructuring Charge		3,519	[1]			7,147	[1]
Adjustments						(81)	[1]
Cash payments		(986)	[1]	(4,715)	[1]	(2,832)	[1]
Foreign exchange		38	[1]	(198)	[1]	81	[1]
Balance at end period		2,848	[1]	277	[1]	5,190	[1]
Employee Severance
Restructuring Cost and Reserve [Line Items]
Balance at beginning period		277		5,035		153
Restructuring Charge		2,471				7,147
Adjustments	134					(134)
Cash payments		(986)		(4,560)		(2,212)
Foreign exchange		6		(198)		81
Balance at end period		1,768		277		5,035
Facility Exit Costs
Restructuring Cost and Reserve [Line Items]
Balance at beginning period				155	[2]	722	[2]
Restructuring Charge		261	[2]
Adjustments						53	[2]
Cash payments				(155)	[2]	(620)	[2]
Foreign exchange		4	[2]
Balance at end period		265	[2]			155	[2]
Acquisition Related Charges
Restructuring Cost and Reserve [Line Items]
Restructuring Charge		787	[2]
Foreign exchange		28	[2]
Balance at end period		$ 815	[2]

[1] All activity prior to July 31, 2012 relates to the Fiscal Year 2011 Restructuring Plan. In fiscal year 2013, the restructuring charge of $3,519, cash payments of $702 and foreign exchange loss of $31 relate to the Fiscal Year 2013 Restructuring Plan, while cash payments of $284 and foreign exchange loss of $7 relate to the Fiscal Year 2011 Restructuring Plan.

[2] Activity in fiscal year 2013 pertains to the Ultrasonix acquisition.