Annual report pursuant to Section 13 and 15(d)

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

v3.10.0.1
Summary of significant accounting policies (Details) - Amount of expense related to share-based payment arrangements - USD ($)
$ in Thousands
12 Months Ended
Jul. 31, 2018
Jul. 31, 2017
Jul. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]      
Share Based Compensation $ 813 $ 831 $ 525
Cost of Clinical Laboratory Services [Member]      
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]      
Share Based Compensation   6 6
Selling, General and Administrative Expenses [Member]      
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]      
Share Based Compensation $ 813 $ 825 $ 519