Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jul. 31, 2015	Jul. 31, 2014
Statement of Financial Position [Abstract]
Trade receivables, allowances	$ 746	$ 681
Inventories, reserves	$ 1,915	$ 2,136
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	25,000,000	25,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	41,462,941	41,152,800
Treasury stock, shares	4,949,111	4,949,111