Condensed Consolidated Balance Sheet Parenthetical - USD ($) $ in Thousands	Apr. 30, 2016	Jul. 31, 2015
Current Assets
Allowance for doubtful accounts	$ 886	$ 761
Other Assets
Accumulated amortization Trademarks and patents	319	301
Accumulated amortization Debt issuance costs	154	133
Accumulated amortization Customer lists	$ 3,119	$ 2,094
Common Stock
Stockholder's Equity
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10
Common stock, shares issued	7,981,243	7,936,343
Treasury stock, common shares	2,923,053	2,932,796
Common Class B
Stockholder's Equity
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10
Common stock, shares issued	2,515,735	2,389,735
Treasury stock, common shares	324,741	324,741