Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Apr. 30, 2018	Jul. 31, 2017
Statement Of Financial Position [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 346	$ 752
Common stock, par value	$ 0.05	$ 0.05
Common stock, shares authorized	30,000,000	30,000,000
Common stock, shares issued	12,503,411	12,467,824
Common stock, shares outstanding	12,503,411	12,467,824