Condensed Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2014	Jan. 31, 2013
Net revenue:
Product	$ 139,471	$ 132,763	$ 247,925	$ 245,310
Engineering	1,966	5,791	3,594	13,111
Total net revenue	141,437	138,554	251,519	258,421
Cost of sales:
Product	78,767	77,340	144,393	146,014
Engineering	1,586	5,815	3,106	11,922
Total cost of sales	80,353	83,155	147,499	157,936
Gross profit	61,084	55,399	104,020	100,485
Operating expenses:
Research and product development	20,026	16,123	38,880	30,197
Selling and marketing	14,695	11,867	29,265	23,522
General and administrative	12,944	13,606	27,860	25,528
Restructuring	335	0	296	0
Total operating expenses	48,000	41,596	96,301	79,247
Income from operations	13,084	13,803	7,719	21,238
Other expenses, net	(357)	(402)	(778)	(1,308)
Income before income taxes	12,727	13,401	6,941	19,930
(Benefit from) provision for income taxes	(6,587)	3,592	(8,598)	5,740
Net income	$ 19,314	$ 9,809	$ 15,539	$ 14,190
Net income per common share:
Basic	$ 1.56	$ 0.80	$ 1.25	$ 1.15
Diluted	$ 1.53	$ 0.78	$ 1.23	$ 1.13
Weighted-average shares outstanding:
Basic	12,417	12,294	12,430	12,304
Diluted	12,656	12,581	12,684	12,574
Dividends declared and paid per share:	$ 0.10	$ 0.10	$ 0.20	$ 0.20