Stock-Based Compensation (Details 4) (USD $)					12 Months Ended						12 Months Ended							12 Months Ended			3 Months Ended	12 Months Ended
	Jul. 31, 2013 Stock options	Jul. 31, 2012 Stock options	Jul. 31, 2011 Stock options	Jul. 31, 2010 Stock options	Jul. 31, 2010 Stock options Non-employee director Awards vesting on the first anniversary	Jul. 31, 2010 Stock options Employee director Awards vesting on the first anniversary	Jul. 31, 2013 Restricted shares	Jul. 31, 2012 Restricted shares	Jul. 31, 2011 Restricted shares	Jul. 31, 2010 Restricted shares	Jul. 31, 2012 Restricted shares Non-employee director Awards vesting on the first anniversary	Jul. 31, 2011 Restricted shares Non-employee director Three year vesting stock awards	Jul. 31, 2011 Restricted shares Member of the Board of Directors Three year vesting stock awards item	Jul. 31, 2011 Restricted shares Employee director Three year vesting stock awards	Jul. 31, 2013 2006 Plan	Jul. 31, 2013 2006 Plan Stock options and stock appreciation rights	Jul. 31, 2013 2006 Plan Restricted stock and other stock awards	Jul. 31, 2013 2006 Plan Stock options	Jul. 31, 2013 2006 Plan Stock options Employees Minimum item	Jul. 31, 2013 2006 Plan Stock options Employees Maximum item	Oct. 31, 2009 2006 Plan Stock options Non-employee director	Jul. 31, 2009 2006 Plan Stock options Member of the Board of Directors	Jul. 31, 2013 2006 Plan Stock options Newly appointed or elected director item	Jul. 31, 2013 2006 Plan Restricted shares item
Stock award plan
Maximum number of shares authorized for issuance															5,591,000	2,700,000	2,891,000
Options granted to each director quarterly (in shares)																					1,688
Options granted to each director on the last day of fiscal year (in shares)					10,125	3,375																3,375
Options granted to each newly appointed or elected director (in shares)																							33,750
Number of equal annual installments in which the options are exercisable																			3	4			3
Percentage of the options exercisable on the first anniversary of the grant date																						50.00%
Percentage of the options exercisable on the second anniversary of the grant date																						50.00%
Termination period following termination of employment or service																		3 months
Expiration term																		5 years
Vesting percentage on each of the first three anniversaries of the grant date													33.33%											33.33%
Number of anniversary dates in which the stock awards vest													3											3
Stock awards granted to each director on the last day of fiscal year (in shares)												3,375		1,125
Annual grant (in dollars)											$ 35,000
Outstanding options to purchase shares of common stock (in shares)	403,831	823,235	1,543,968	3,212,691														403,831
Outstanding unvested restricted stock shares							605,767	708,008	545,838	356,967														605,767
Shares available for issuance																416,810	891,257