Accrued Expenses and Other (Details 1) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jul. 31, 2012	Jul. 31, 2011
Product warranty liability
Balance at beginning of period	$ 185	$ 223
Accruals for warranty liability	99	145
Warranty charges	(118)	(183)
Balance at end of period	$ 166	$ 185