Annual report pursuant to Section 13 and 15(d)

Summary of significant accounting policies (Details) - Amount of expense related to share-based payment arrangements

v2.4.0.8
Summary of significant accounting policies (Details) - Amount of expense related to share-based payment arrangements (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Jul. 31, 2014
Jul. 31, 2013
Jul. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]      
Share Based Compensation $ 594 $ 545 $ 719
Cost of Clinical Laboratory Services [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]      
Share Based Compensation 9 10 10
Research and Development Expense [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]      
Share Based Compensation 1 2 4
Selling, General and Administrative Expenses [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]      
Share Based Compensation $ 584 $ 533 $ 705