Annual report pursuant to Section 13 and 15(d)

Revenue Recognition (Details)

v3.19.3
Revenue Recognition (Details) - USD ($)
12 Months Ended
Jul. 31, 2019
Jul. 31, 2018
Jul. 31, 2017
Revenue Recognition (Details) [Line Items]      
Royalty Income, Nonoperating (in Dollars) $ 0    
Third-Party Payers And Health Maintenance Organizations [Member] | Minimum [Member]      
Revenue Recognition (Details) [Line Items]      
BillingInformationFilingDeadlinePeriod 60 days    
Third-Party Payers And Health Maintenance Organizations [Member] | Maximum [Member]      
Revenue Recognition (Details) [Line Items]      
BillingInformationFilingDeadlinePeriod 90 days    
Government Payer Medicare [Member]      
Revenue Recognition (Details) [Line Items]      
BillingInformationFilingDeadlinePeriod 60 days    
Patient self-pay [Member]      
Revenue Recognition (Details) [Line Items]      
Billing Period 210 days    
Receivable Collection Period 180 days    
Products Revenue And Royalty Income [Member]      
Revenue Recognition (Details) [Line Items]      
Claim Period For Return Of Goods 30 days    
Royalty Income, Nonoperating (in Dollars)   $ 712,000 $ 1,205,000
Products Revenue And Royalty Income [Member] | Minimum [Member]      
Revenue Recognition (Details) [Line Items]      
Receivable Collection Period 30 days    
Products Revenue And Royalty Income [Member] | Maximum [Member]      
Revenue Recognition (Details) [Line Items]      
Receivable Collection Period 90 days    
Clinical Services [Member] | Revenue Benchmark [Member]      
Revenue Recognition (Details) [Line Items]      
Concentration Risk, Percentage 63.00% 71.00% 71.00%
Clinical Services [Member] | Revenue Benchmark [Member] | Third-Party Payers And Health Maintenance Organizations [Member]      
Revenue Recognition (Details) [Line Items]      
Concentration Risk, Percentage 36.00% 39.00% 39.00%