Computation of Basic and Diluted Net Income Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended
		Oct. 31, 2017	Oct. 31, 2016
Earnings Per Share [Abstract]
Net income		$ 5,659	$ 2,531
Weighted average number of common shares outstanding-basic		12,473	12,419
Effect of dilutive securities:
Stock options and restricted stock units		126	197
Weighted average number of common shares outstanding-diluted		12,599	12,616
Basic net income per share		$ 0.45	$ 0.20
Diluted net income per share		$ 0.45	$ 0.20
Anti-dilutive shares related to outstanding stock options and unvested restricted stock	[1]	26	1

[1] These shares related to outstanding stock options and unvested restricted stock were not included in our calculations of diluted earnings per share, as the effect of including them would be anti-dilutive.