Commitments and Guarantees - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended			9 Months Ended	3 Months Ended		9 Months Ended			1 Months Ended
	Apr. 30, 2013	Apr. 30, 2013	Apr. 30, 2012	Jul. 31, 2012	Apr. 30, 2013 Minimum	Apr. 30, 2013 Maximum	Apr. 30, 2012 Maximum	Apr. 30, 2013 Maximum	Apr. 30, 2012 Maximum	Apr. 30, 2013 Ultrasonix	Oct. 11, 2011 Credit Agreement	Apr. 30, 2013 Credit Agreement	Jul. 31, 2012 Credit Agreement	Apr. 30, 2013 Credit Agreement Other Revolving Credit Facilities	Apr. 30, 2013 Product Extended Warranty Contracts	Jul. 31, 2012 Product Extended Warranty Contracts
Commitments and Contingencies Disclosure [Line Items]
Standard product warranty term					12 months			36 months
Deferred revenue for product extended warranty contracts	$ 11,636	$ 11,636		$ 12,267											$ 7,427	$ 7,207
Credit facility maximum borrow capacity											100,000
Number of banks											3
Revolving credit agreement period											5 years
Credit agreement expiry date											Oct. 10, 2016
Aggregate available credit amount under specified circumstances											150,000
Percentage of capital stock pledge as collateral											65.00%
Credit facility available borrowing capacity														12,000
Credit facility paid		3,014								784
Credit facility amount borrowed		2,230
Line of credit amount outstanding												0	0
Percentage of revenue						0.20%	0.50%	0.30%	0.50%
Employee termination costs			400
Business exit cost	$ 334	$ 739	$ 1,203