Annual report pursuant to Section 13 and 15(d)

Summary of significant accounting policies (Details)

v2.4.0.8
Summary of significant accounting policies (Details) (USD $)
 12 Months Ended
Jul. 31, 2014
Jul. 31, 2013
Jul. 31, 2012
Jul. 31, 2011
Summary of significant accounting policies (Details) [Line Items]        
Number of Operating Segments 3      
Cash and Cash Equivalents, at Carrying Value $ 17,455,000 $ 9,007,000 $ 15,076,000 $ 14,161,000
Contractual Adjustment Percentage 86.00% 85.00% 85.00%  
Maximum Period for Allowance for Doubtful Accounts 210 days 210 days    
Percentage Of Account Receivable Over Specified Days 100.00% 100.00%    
Finite-Lived Intangible Asset, Useful Life 10 years      
Impairment of Long-Lived Assets Held-for-use 0 0 0  
Indefinite-Lived Intangible Assets (Excluding Goodwill)     0  
Advertising Expense 440,000 302,000 237,000  
Share-based Compensation 594,000 545,000 719,000  
Excess Tax Benefit from Share-based Compensation, Operating Activities 0 0 0  
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options 462,000      
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition 14 months      
Unvested Restricted Stock [Member]
        
Summary of significant accounting policies (Details) [Line Items]        
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in Shares) 159,000 32,000 0  
In the Money Stock Options [Member]
        
Summary of significant accounting policies (Details) [Line Items]        
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in Shares) 159,000 32,000 0  
Outstanding Options [Member]
        
Summary of significant accounting policies (Details) [Line Items]        
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in Shares) 604,000 727,000 736,000  
Building and Building Improvements [Member] | Minimum [Member]
        
Summary of significant accounting policies (Details) [Line Items]        
Property, Plant and Equipment, Estimated Useful Lives 15      
Building and Building Improvements [Member] | Maximum [Member]
        
Summary of significant accounting policies (Details) [Line Items]        
Property, Plant and Equipment, Estimated Useful Lives 30      
Machinery and Equipment [Member] | Minimum [Member]
        
Summary of significant accounting policies (Details) [Line Items]        
Property, Plant and Equipment, Estimated Useful Lives 3      
Machinery and Equipment [Member] | Maximum [Member]
        
Summary of significant accounting policies (Details) [Line Items]        
Property, Plant and Equipment, Estimated Useful Lives 10      
Clinical Labs [Member] | United Health Care of New York [Member]
        
Summary of significant accounting policies (Details) [Line Items]        
Sales Revenue Services Net Percentage 25.00% 22.00% 21.00%  
Clinical Labs [Member]
        
Summary of significant accounting policies (Details) [Line Items]        
Sales Revenue Services Net Percentage 100.00% 100.00% 100.00%  
Receivable Percentage 60.00% 60.00%    
Life Sciences [Member]
        
Summary of significant accounting policies (Details) [Line Items]        
Royalties Receivable 1,000,000 1,200,000    
Foreign Bank [Member]
        
Summary of significant accounting policies (Details) [Line Items]        
Cash and Cash Equivalents, at Carrying Value $ 1,100,000 $ 1,500,000    
Minimum [Member]
        
Summary of significant accounting policies (Details) [Line Items]        
Finite-Lived Intangible Asset, Useful Life 4 years      
Maximum [Member]
        
Summary of significant accounting policies (Details) [Line Items]        
Finite-Lived Intangible Asset, Useful Life 15 years