Annual report pursuant to Section 13 and 15(d)

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

v3.7.0.1
Summary of significant accounting policies (Details) - Amount of expense related to share-based payment arrangements - USD ($)
$ in Thousands
12 Months Ended
Jul. 31, 2017
Jul. 31, 2016
Jul. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]      
Share Based Compensation $ 831 $ 525 $ 429
Cost of Clinical Laboratory Services [Member]      
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]      
Share Based Compensation 6 6 5
Research and Development Expense [Member]      
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]      
Share Based Compensation     2
Selling, General and Administrative Expenses [Member]      
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]      
Share Based Compensation $ 825 $ 519 $ 422