Annual report pursuant to Section 13 and 15(d)

Summary of significant accounting policies (Details) - Segment's net revenues and revenue percentages

v3.5.0.2
Summary of significant accounting policies (Details) - Segment's net revenues and revenue percentages - USD ($)
$ in Thousands
 12 Months Ended
Jul. 31, 2016
Jul. 31, 2015
Jul. 31, 2014
Summary of significant accounting policies (Details) - Segment's net revenues and revenue percentages [Line Items]      
Sales Revenue Services Net $ 70,915 $ 63,414 $ 58,689
Clinical Labs [Member]      
Summary of significant accounting policies (Details) - Segment's net revenues and revenue percentages [Line Items]      
Sales Revenue Services Net $ 70,915 $ 63,414 $ 58,689
Sales Revenue Services Net Percentage 100.00% 100.00% 100.00%
Third-Party Payor [Member] | Clinical Labs [Member]      
Summary of significant accounting policies (Details) - Segment's net revenues and revenue percentages [Line Items]      
Sales Revenue Services Net $ 40,211 $ 35,631 $ 29,509
Sales Revenue Services Net Percentage 57.00% 56.00% 50.00%
Self-Pay [Member] | Clinical Labs [Member]      
Summary of significant accounting policies (Details) - Segment's net revenues and revenue percentages [Line Items]      
Sales Revenue Services Net $ 14,744 $ 11,028 $ 11,204
Sales Revenue Services Net Percentage 21.00% 17.00% 19.00%
Medicare [Member] | Clinical Labs [Member]      
Summary of significant accounting policies (Details) - Segment's net revenues and revenue percentages [Line Items]      
Sales Revenue Services Net $ 11,392 $ 11,981 $ 12,815
Sales Revenue Services Net Percentage 16.00% 19.00% 22.00%
Health Maintenance Organizations [Member] | Clinical Labs [Member]      
Summary of significant accounting policies (Details) - Segment's net revenues and revenue percentages [Line Items]      
Sales Revenue Services Net $ 4,568 $ 4,774 $ 5,161
Sales Revenue Services Net Percentage 6.00% 8.00% 9.00%