Annual report pursuant to Section 13 and 15(d)

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

v2.4.0.6
Summary of significant accounting policies (Detail) - Net accounts receivable by segment (USD $)
In Thousands, unless otherwise specified
Jul. 31, 2012
Jul. 31, 2011
Clinical Labs (by billing category)    
Accounts Receivable Net Current $ 14,135 $ 15,245
Clinical Labs [Member] | Medicare [Member]
   
Clinical Labs (by billing category)    
Accounts Receivable Net Current 1,270 1,434
Accounts Receivable Net Current Percentage 16.00% 19.00%
Clinical Labs [Member] | Third-Party Payor [Member]
   
Clinical Labs (by billing category)    
Accounts Receivable Net Current 3,478 3,087
Accounts Receivable Net Current Percentage 45.00% 40.00%
Clinical Labs [Member] | Self-Pay [Member]
   
Clinical Labs (by billing category)    
Accounts Receivable Net Current 2,655 2,865
Accounts Receivable Net Current Percentage 35.00% 37.00%
Clinical Labs [Member] | Health Maintenance Organizations [Member]
   
Clinical Labs (by billing category)    
Accounts Receivable Net Current 330 314
Accounts Receivable Net Current Percentage 4.00% 4.00%
Clinical Labs [Member]
   
Clinical Labs (by billing category)    
Accounts Receivable Net Current 7,733 7,700
Accounts Receivable Net Current Percentage 100.00% 100.00%
Life Sciences [Member]
   
Clinical Labs (by billing category)    
Accounts Receivable Net Current $ 6,402 $ 7,545