Annual report pursuant to Section 13 and 15(d)

Segment reporting (Details) - Geographic financial information

v3.3.0.814
Segment reporting (Details) - Geographic financial information - USD ($)
$ in Thousands
 12 Months Ended
Jul. 31, 2015
Jul. 31, 2014
Jul. 31, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]      
Net sales to unaffiliated customers $ 97,599 $ 95,947 $ 93,707
Long-lived assets at July 31,      
Long-lived assets 21,555 23,290 26,012
UNITED STATES      
Revenues from External Customers and Long-Lived Assets [Line Items]      
Net sales to unaffiliated customers 87,875 84,389 80,559
Long-lived assets at July 31,      
Long-lived assets 19,799 20,854 23,136
SWITZERLAND      
Revenues from External Customers and Long-Lived Assets [Line Items]      
Net sales to unaffiliated customers 3,131 4,130 5,499
Long-lived assets at July 31,      
Long-lived assets 1,224 1,629 1,984
UNITED KINGDOM      
Revenues from External Customers and Long-Lived Assets [Line Items]      
Net sales to unaffiliated customers 1,904 2,023 2,324
Long-lived assets at July 31,      
Long-lived assets 357 462 491
Other International Countries [Member]      
Revenues from External Customers and Long-Lived Assets [Line Items]      
Net sales to unaffiliated customers 4,689 5,405 5,325
Long-lived assets at July 31,      
Long-lived assets $ 175 $ 345 $ 401