Condensed Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Apr. 30, 2014	Apr. 30, 2013	Apr. 30, 2014	Apr. 30, 2013
Net revenue:
Product	$ 122,067	$ 121,188	$ 369,992	$ 366,498
Engineering	1,965	4,577	5,559	17,688
Total net revenue	124,032	125,765	375,551	384,186
Cost of sales:
Product	68,717	72,341	213,110	218,355
Engineering	1,961	4,284	5,067	16,206
Total cost of sales	70,678	76,625	218,177	234,561
Gross profit	53,354	49,140	157,374	149,625
Operating expenses:
Research and product development	16,915	16,127	55,795	46,324
Selling and marketing	14,338	13,540	43,603	37,062
General and administrative	12,764	12,265	40,624	37,793
Restructuring	(80)	496	216	496
Total operating expenses	43,937	42,428	140,238	121,675
Income from operations	9,417	6,712	17,136	27,950
Other income (expenses), net	882	190	104	(1,118)
Income before income taxes	10,299	6,902	17,240	26,832
Provision for (benefit from) income taxes	2,509	1,678	(6,089)	7,418
Net income	$ 7,790	$ 5,224	$ 23,329	$ 19,414
Net income per common share:
Basic	$ 0.63	$ 0.42	$ 1.88	$ 1.58
Diluted	$ 0.62	$ 0.41	$ 1.84	$ 1.54
Weighted-average shares outstanding:
Basic	12,403	12,305	12,421	12,300
Diluted	12,647	12,620	12,679	12,584
Dividends declared and paid per share:	$ 0.10	$ 0.10	$ 0.30	$ 0.30