Annual report pursuant to Section 13 and 15(d)

Summary of significant accounting policies (Details) - Net accounts receivable by segment

v3.7.0.1
Summary of significant accounting policies (Details) - Net accounts receivable by segment - USD ($)
$ in Thousands
Jul. 31, 2017
Jul. 31, 2016
Summary of significant accounting policies (Details) - Net accounts receivable by segment [Line Items]    
Accounts Receivable Net Current $ 15,180 $ 14,592
Clinical Labs [Member]    
Summary of significant accounting policies (Details) - Net accounts receivable by segment [Line Items]    
Accounts Receivable Net Current $ 11,401 $ 10,364
Accounts Receivable Net Current Percentage 100.00% 100.00%
Clinical Labs [Member] | Third-Party Payor [Member]    
Summary of significant accounting policies (Details) - Net accounts receivable by segment [Line Items]    
Accounts Receivable Net Current $ 7,256 $ 5,861
Accounts Receivable Net Current Percentage 64.00% 57.00%
Clinical Labs [Member] | Self-Pay [Member]    
Summary of significant accounting policies (Details) - Net accounts receivable by segment [Line Items]    
Accounts Receivable Net Current $ 1,591 $ 1,676
Accounts Receivable Net Current Percentage 14.00% 16.00%
Clinical Labs [Member] | Medicare [Member]    
Summary of significant accounting policies (Details) - Net accounts receivable by segment [Line Items]    
Accounts Receivable Net Current $ 1,385 $ 1,486
Accounts Receivable Net Current Percentage 12.00% 14.00%
Clinical Labs [Member] | Health Maintenance Organizations [Member]    
Summary of significant accounting policies (Details) - Net accounts receivable by segment [Line Items]    
Accounts Receivable Net Current $ 1,169 $ 1,341
Accounts Receivable Net Current Percentage 10.00% 13.00%
Life Sciences [Member]    
Summary of significant accounting policies (Details) - Net accounts receivable by segment [Line Items]    
Accounts Receivable Net Current $ 3,779 $ 4,228