Condensed Consolidated Statements of Operations - USD ($)	3 Months Ended
	Oct. 31, 2015	Oct. 31, 2014
Income Statement [Abstract]
Net sales	$ 64,117,000	$ 76,391,000
Cost of sales	35,915,000	41,066,000
Gross profit	28,202,000	35,325,000
Expenses:
Selling, general and administrative	16,718,000	15,526,000
Research and development	7,940,000	10,019,000
Amortization of intangibles	1,376,000	1,561,000
Total operating expenses	26,034,000	27,106,000
Operating income	2,168,000	8,219,000
Other expenses (income):
Interest expense	75,000	265,000
Interest income and other	(112,000)	(84,000)
Income before provision for income taxes	2,205,000	8,038,000
Provision for income taxes	766,000	2,813,000
Net income	$ 1,439,000	$ 5,225,000
Net income per share (See Note 4):
Basic (in dollars per share)	$ 0.09	$ 0.32
Diluted (in dollars per share)	$ 0.09	$ 0.32
Weighted average number of common shares outstanding – basic (in shares)	16,171,000	16,217,000
Weighted average number of common and common equivalent shares outstanding – diluted (in shares)	16,194,000	16,513,000
Dividends declared per issued and outstanding common share as of the applicable dividend record date (in dollars per share)	$ 0.30	$ 0.30