Consolidated Statements of Income (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010
Consolidated Statements of Income [Abstract]
Net sales	$ 60,014	$ 55,657	$ 52,010
Cost of sales	25,495	22,876	22,050
Gross profit	34,519	32,781	29,960
Operating expenses
Research and development	3,642	3,713	3,008
Sales and marketing	11,881	11,474	11,958
General and administrative	10,515	9,245	8,903
Total operating expenses	26,038	24,432	23,869
Operating income	8,481	8,349	6,091
Other income (expenses)
Investment income	40	99	38
Interest expense	(43)	(202)	(491)
Settlement gain	0	0	2,398
Gain (loss) on sale of product line	0	(99)	817
Miscellaneous	(11)	(11)	23
Total other income (expenses)	(14)	(213)	2,785
Income from continuing operations before provision for income taxes	8,467	8,136	8,876
Provision for income taxes	2,499	2,467	3,109
Income from continuing operations	5,968	5,669	5,767
Loss from discontinued operations, net of income tax benefit of $193, $24 and $17, respectively	382	36	34
Net income	$ 5,586	$ 5,633	$ 5,733
Basic
Income from continuing operations (in dollars per share)	$ 0.24	$ 0.23	$ 0.23
Loss from discontinued operations (in dollars per share)	$ (0.02)	$ 0.00	$ 0.00
Net income (in dollars per share)	$ 0.22	$ 0.23	$ 0.23
Diluted
Income from continuing operations (in dollars per share)	$ 0.24	$ 0.23	$ 0.23
Loss from discontinued operations (in dollars per share)	$ (0.02)	$ 0.00	$ 0.00
Net income (in dollars per share)	$ 0.22	$ 0.23	$ 0.23
Basic weighted average common shares outstanding (in share)	25,100,064	24,901,832	24,618,403
Diluted weighted average common shares outstanding (in share)	25,256,584	25,035,095	24,672,605