Quarterly report pursuant to Section 13 or 15(d)

Goodwill and intangible assets (Details)

v3.8.0.1
Goodwill and intangible assets (Details) - USD ($)
$ in Thousands
6 Months Ended
Jan. 31, 2018
Jul. 31, 2017
Goodwill and intangible assets (Details) [Line Items]    
Goodwill $ 7,452 $ 7,452
Intangible Assets, Amortization Period [Member]    
Goodwill and intangible assets (Details) [Line Items]    
Finite-Lived Intangible Asset, Useful Life 2 years  
Clinical Labs [Member]    
Goodwill and intangible assets (Details) [Line Items]    
Goodwill $ 7,452 $ 7,452