Annual report pursuant to Section 13 and 15(d)

Summary of significant accounting policies (Detail)

v2.4.0.6
Summary of significant accounting policies (Detail) (USD $)
12 Months Ended
Jul. 31, 2012
Jul. 31, 2011
Jul. 31, 2010
Number of Operating Segments 3    
Contractual Adjustment Percentage 85.00% 84.00% 83.00%
Advertising Expense (in Dollars) $ 237,000 $ 235,000 $ 375,000
Unvested Restricted Stock Excluded From Calculation of Diluted Earnings Per Share (in Shares) 0 27,000 51,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in Shares) 736,000 785,000 1,132,000
Share-based Compensation (in Dollars) 719,000 1,049,000 1,170,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Stock Options (in Dollars)   657,000  
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition 15 months    
Clinical Labs [Member] | United Healthcare of New York [Member]
     
Sales Revenue Services Net Percentage 21.00% 22.00% 25.00%
Clinical Labs [Member] | Another Third Party Provider [Member]
     
Sales Revenue Services Net Percentage 13.00% 11.00%  
Clinical Labs [Member]
     
Sales Revenue Services Net Percentage 100.00% 100.00% 100.00%
Receivable Percentage 55.00% 51.00%  
Share-based Compensation (in Dollars) 59,000 71,000 90,000
Life Sciences [Member]
     
Royalties Receivable (in Dollars) 1,700,000 2,000,000  
Share-based Compensation (in Dollars) $ 63,000 $ 98,000 $ 128,000
Building and Building Improvements [Member] | Minimum [Member]
     
Property, Plant and Equipment, Estimated Useful Lives 15    
Building and Building Improvements [Member] | Maximum [Member]
     
Property, Plant and Equipment, Estimated Useful Lives 30    
Machinery and Equipment [Member] | Minimum [Member]
     
Property, Plant and Equipment, Estimated Useful Lives 3    
Machinery and Equipment [Member] | Maximum [Member]
     
Property, Plant and Equipment, Estimated Useful Lives 10    
Minimum [Member]
     
Finite-Lived Intangible Asset, Useful Life 4 years    
Maximum [Member]
     
Finite-Lived Intangible Asset, Useful Life 15 years