Annual report pursuant to Section 13 and 15(d)

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

v3.19.3
Summary of significant accounting policies (Details) - Net accounts receivable by segment - USD ($)
$ in Thousands
Jul. 31, 2019
Jul. 31, 2018
Summary of significant accounting policies (Details) - Net accounts receivable by segment [Line Items]    
Accounts Receivable Net Current $ 10,738 $ 13,147
Clinical Labs [Member]    
Summary of significant accounting policies (Details) - Net accounts receivable by segment [Line Items]    
Accounts Receivable Net Current $ 6,800 $ 9,771
Accounts Receivable Net Current Percentage 100.00% 100.00%
Clinical Labs [Member] | Third-Party Payer [Member]    
Summary of significant accounting policies (Details) - Net accounts receivable by segment [Line Items]    
Accounts Receivable Net Current $ 2,956 $ 4,692
Accounts Receivable Net Current Percentage 44.00% 48.00%
Clinical Labs [Member] | Patient self-pay [Member]    
Summary of significant accounting policies (Details) - Net accounts receivable by segment [Line Items]    
Accounts Receivable Net Current $ 2,360 $ 2,010
Accounts Receivable Net Current Percentage 35.00% 20.00%
Clinical Labs [Member] | Medicare [Member]    
Summary of significant accounting policies (Details) - Net accounts receivable by segment [Line Items]    
Accounts Receivable Net Current $ 910 $ 1,740
Accounts Receivable Net Current Percentage 13.00% 18.00%
Clinical Labs [Member] | Health Maintenance Organizations [Member]    
Summary of significant accounting policies (Details) - Net accounts receivable by segment [Line Items]    
Accounts Receivable Net Current $ 574 $ 1,329
Accounts Receivable Net Current Percentage 8.00% 14.00%
Life Sciences [Member]    
Summary of significant accounting policies (Details) - Net accounts receivable by segment [Line Items]    
Accounts Receivable Net Current $ 3,938 $ 3,376