Commitments, Guarantees and Contingencies - Additional Information (Detail) (USD $)	12 Months Ended						1 Months Ended	12 Months Ended		1 Months Ended		1 Months Ended	12 Months Ended		1 Months Ended
	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2013 Minimum	Jul. 31, 2013 Maximum	Jul. 31, 2012 Maximum	Jul. 31, 2013 Ultrasonix Acquisition	Oct. 11, 2011 Credit Agreement	Jul. 31, 2013 Credit Agreement	Jul. 31, 2012 Credit Agreement	Oct. 11, 2011 Credit Agreement Minimum	Jul. 31, 2013 Credit Agreement Minimum	Oct. 11, 2011 Credit Agreement Maximum	Jul. 31, 2013 Credit Agreement Maximum	Jul. 31, 2013 Credit Agreement Other Revolving Credit Facilities	Oct. 11, 2011 Credit Agreement Libor Rate Minimum	Oct. 11, 2011 Credit Agreement Libor Rate Maximum	Oct. 11, 2011 Credit Agreement Defined Base Rate Minimum	Oct. 11, 2011 Credit Agreement Defined Base Rate Maximum	Oct. 11, 2011 Credit Agreement Federal Funds Rate	Oct. 11, 2011 Credit Agreement One Month London Inter Bank Offer Rate	Jul. 31, 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	$ 10,584,000	$ 12,267,000																			$ 8,018,000	$ 7,207,000
Credit facility maximum borrow capacity							100,000,000
Revolving credit agreement period							5 years
Percentage of capital stock pledge as collateral							65.00%
Aggregate available credit amount under specified circumstances							150,000,000
Variable interest rate															1.25%	2.00%	0.00%	1.00%	0.50%	1.00%
Credit facility commitment fee percentage										0.20%		0.35%
Leverage ratio of total debt to earnings before interest tax depreciation amortization													275.00%
Interest coverage ratio											300.00%
Leverage ratio								0.50%
Credit facility transaction costs incurred								500,000
Credit facility, maturity period								5 years
Credit facility available borrowing capacity														12,025,000
Credit facility paid	3,014,000					784,000
Credit facility amount borrowed	2,230,000
Line of credit amount outstanding								0	0
Percentage of revenue				0.20%	1.30%
Employee termination costs	0	400,000
Business exit cost	$ 1,211,000	$ 1,288,000