Condensed Consolidated Statements of Operations (USD $)	3 Months Ended		6 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2013	Jan. 31, 2012
Net sales	$ 74,577,000	$ 99,141,000	$ 165,530,000	$ 212,502,000
Cost of sales	42,337,000	57,725,000	91,487,000	119,806,000
Gross profit	32,240,000	41,416,000	74,043,000	92,696,000
Expenses:
Selling, general and administrative	15,433,000	19,626,000	32,243,000	43,744,000
Research and development	9,278,000	9,444,000	19,327,000	19,128,000
Amortization of intangibles	1,582,000	1,692,000	3,164,000	3,411,000
Total operating expenses	26,293,000	30,762,000	54,734,000	66,283,000
Operating income	5,947,000	10,654,000	19,309,000	26,413,000
Other expenses (income):
Interest expense	2,030,000	2,183,000	4,141,000	4,329,000
Interest income and other	(315,000)	(434,000)	(591,000)	(930,000)
Income before provision for income taxes	4,232,000	8,905,000	15,759,000	23,014,000
Provision for income taxes	1,867,000	3,084,000	5,959,000	4,592,000
Net income	$ 2,365,000	$ 5,821,000	$ 9,800,000	$ 18,422,000
Net income per share:
Basic	$ 0.14	$ 0.29	$ 0.57	$ 0.85
Diluted	$ 0.14	$ 0.27	$ 0.51	$ 0.75
Weighted average number of common shares outstanding - basic	17,300,000	20,087,000	17,340,000	21,672,000
Weighted average number of common and common equivalent shares outstanding - diluted	17,401,000	26,056,000	23,394,000	27,588,000
Dividends declared per issued and outstanding common share as of the applicable dividend record date	$ 0.275	$ 0.275	$ 0.55	$ 0.55