Condensed Consolidated Statements of Operations (USD $)	3 Months Ended		9 Months Ended
	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2013	Apr. 30, 2012
Net sales	$ 69,856,000	$ 99,793,000	$ 235,386,000	$ 312,295,000
Cost of sales	38,429,000	58,115,000	129,916,000	177,921,000
Gross profit	31,427,000	41,678,000	105,470,000	134,374,000
Expenses:
Selling, general and administrative	15,374,000	20,005,000	47,617,000	63,749,000
Research and development	9,080,000	9,481,000	28,407,000	28,609,000
Amortization of intangibles	1,582,000	1,626,000	4,746,000	5,037,000
Total operating expenses	26,036,000	31,112,000	80,770,000	97,395,000
Operating income	5,391,000	10,566,000	24,700,000	36,979,000
Other expenses (income):
Interest expense	2,009,000	2,192,000	6,150,000	6,521,000
Interest income and other	(287,000)	(370,000)	(878,000)	(1,300,000)
Income before provision for income taxes	3,669,000	8,744,000	19,428,000	31,758,000
Provision for income taxes	817,000	2,678,000	6,776,000	7,270,000
Net income	$ 2,852,000	$ 6,066,000	$ 12,652,000	$ 24,488,000
Net income per share:
Basic	$ 0.17	$ 0.32	$ 0.74	$ 1.18
Diluted	$ 0.17	$ 0.29	$ 0.69	$ 1.04
Weighted average number of common shares outstanding - basic	16,731,000	18,853,000	17,141,000	20,746,000
Weighted average number of common and common equivalent shares outstanding - diluted	16,827,000	24,910,000	23,221,000	26,724,000
Dividends declared per issued and outstanding common share as of the applicable dividend record date	$ 0.275	$ 0.275	$ 0.825	$ 0.825