Geographic Areas Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2012	Oct. 31, 2011	Jul. 31, 2011	Apr. 30, 2011	Jan. 31, 2011	Oct. 31, 2010	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 151,011	$ 121,270	$ 126,433	$ 117,857	$ 135,349	$ 117,171	$ 117,253	$ 103,822	$ 516,571	$ 473,595	$ 414,813
Long-lived assets	96,769				83,157				96,769	83,157	69,403
UNITED STATES
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									199,518	161,720	139,474
Long-lived assets	50,718				42,212				50,718	42,212	37,251
JAPAN
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									81,907	76,429	72,545
GERMANY
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									63,491	56,330	49,358
NETHERLANDS
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									61,368	51,600	50,011
Other Countries
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									110,287	127,516	103,425
Long-lived assets	8,524				8,681				8,524	8,681	9,412
DENMARK
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	18,574				22,789				18,574	22,789	21,823
CHINA
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 18,953				$ 9,475				$ 18,953	$ 9,475	$ 917