Annual report pursuant to Section 13 and 15(d)

Income taxes (Details)

v2.4.0.8
Income taxes (Details) (USD $)
12 Months Ended 12 Months Ended
Jul. 31, 2013
Jul. 31, 2012
Jul. 31, 2013
Domestic Tax Authority [Member]
Minimum [Member]
Jul. 31, 2013
Domestic Tax Authority [Member]
Maximum [Member]
Jul. 31, 2013
U.S. Federal Tax [Member]
Jul. 31, 2013
Minimum [Member]
Research Tax Credit Carryforward [Member]
Jul. 31, 2013
Minimum [Member]
Jul. 31, 2013
Maximum [Member]
Research Tax Credit Carryforward [Member]
Jul. 31, 2013
Maximum [Member]
Income taxes (Details) [Line Items]                  
Deferred Tax Liabilities, Net $ 200,000 $ 938,000              
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration 102,500,000                
Operating Loss Carryforwards Expiration Year     2018 2033          
Deferred Tax Assets Research and Development and Other Tax Credit Carryforwards 1,013,000 795,000     900,000        
Tax Credit Carryforward Expiration Year           2025   2033  
Foreign Loss Carryforwards 3,700,000                
Operating Loss Carryforwards On Acquisitions 700,000                
Undistributed Earnings of Foreign Subsidiaries 252,000                
Liability for Uncertain Tax Position $ 0                
Income Tax Examination, Year under Examination             2010   2012