Annual report pursuant to Section 13 and 15(d)

Commitments (Details)

v3.5.0.2
Commitments (Details) - USD ($)
$ in Thousands
 12 Months Ended
Jul. 31, 2016
Jul. 31, 2015
Jul. 31, 2014
Commitments (Details) [Line Items]      
Description Of Operating Leases The Company leases equipment, office and laboratory space underseveral non-cancellable operating leases that expire between September 2015 and May 2023. Certain leases include renewal optionsand rent escalation clauses. An entity owned by certain executive officers/directors of the Company owns the building that theCompany leases as its main facility for clinical laboratory operations and certain research operations. In March 2005, the Companyamended and extended the lease for 12 years. In addition to the minimum annual rentals of space, the lease is subject to annualincreases, based on the consumer price index. Annual increases are limited to 3% per year.    
Lease Extension Period 12 years    
Maximum Annual Rental Increase Percentage 3.00%    
Rent expense Including Real Estate Taxes $ 1,704 $ 1,623 $ 1,649
Amount of Real Estate Tax Abatement Received   61  
Operating Leases, Rent Expense 4,572 $ 4,504 $ 4,488
Operating Leases, Rent Expense, Sublease Rentals $ 323    
Agreement Renew Period 2 years    
Other Commitment, Due in Next Twelve Months $ 2,271    
Minimum [Member]      
Commitments (Details) [Line Items]      
Lease Expiration Month and Year September 2015    
Maximum [Member]      
Commitments (Details) [Line Items]      
Lease Expiration Month and Year May 2023