Income Tax Matters (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010
Deferred tax assets:
Accounts receivable	$ 85	$ 78
Inventories	185	168
Accrued liabilities	165	162
Deferred revenue	6,423	6,265
Other	813	384
Loss on foreign subsidiaries	1,949	1,898
Deferred tax assets	9,620	8,955
Deferred tax liability
Property and equipment	1,362	915
Other intangible assets	2,923	2,333
Deferred tax liability	4,285	3,248
Deferred tax assets (liability), net	5,335	5,707
Deferred tax amounts classified on consolidated balance sheets
Current assets	1,247	792
Long-term asset (liability)	4,088	4,915
Deferred tax amounts	5,335	5,707
Provision for income taxes [Abstract]
Current payable	2,153	8,831	3,680
Deferred income taxes	153	(6,388)	(588)
Provision for income taxes	$ 2,499	$ 2,467	$ 3,109
Reconciliation of income tax at statutory rate to effective rate [Abstract]
Computed at the statutory rate (in hundredths)	34.00%	35.00%	34.00%
State taxes, net of federal tax benefit (in hundredths)	2.40%	2.30%	3.00%
Production deduction for domestic manufacturers (in hundredths)	(2.90%)	(2.90%)	(2.00%)
Research and experimentation (in hundredths)	(0.80%)	(3.50%)	(0.60%)
Other (in hundredths)	(3.20%)	(0.60%)	0.60%
Effective income tax rate (in hundredths)	29.50%	30.30%	35.00%