Stockholder's Equity (Details Textuals 2) - USD ($)	12 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014	Dec. 31, 2007
Employee Stock Purchase Plan (ESPP)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock authorized to purchase	5,000,000
Discount from market price	15.00%
Offering period		6 months
Maximum percentage of salary withheld for employee contribution	up to 10%
Compensation contribution limit in percentage	may not exceed 15
Number of shares of common stock issued pursuant to the ESPP	108,132	101,015	81,967
Common stock have been issued pursuant to the ESPP	4,050,226
Shares were available for future grant under the Plan (in shares)	989,811
Maximum annual contributions per employee, percent		10.00%
Share-based compensation arrangement by share-based payment award, maximum employee contribution permitted value	$ 25,000
Maximum annual contributions per employee, conditional percent		15.00%
2007 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock authorized to purchase				8,000,000
Shares were available for future grant under the Plan (in shares)				1,360,067