Consolidated Statements of Operations - USD ($) shares in Thousands	12 Months Ended
	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
Net revenue:
Product	$ 484,173,000	$ 502,752,000	$ 531,161,000
Engineering	2,199,000	6,096,000	9,130,000
Total net revenue	486,372,000	508,848,000	540,291,000
Cost of sales:
Product	282,096,000	275,632,000	302,974,000
Engineering	4,985,000	5,151,000	7,830,000
Total cost of sales	287,081,000	280,783,000	310,804,000
Gross profit	199,291,000	228,065,000	229,487,000
Operating expenses:
Research and product development	63,505,000	67,119,000	68,462,000
Selling and marketing	67,805,000	65,266,000	63,489,000
General and administrative	43,064,000	60,826,000	57,291,000
Restructuring	7,167,000	9,641,000	(354,000)
Asset impairment charges	84,510,000	0	0
Total operating expenses	266,051,000	202,852,000	188,888,000
(Loss) income from operations	(66,760,000)	25,213,000	40,599,000
Other income (expense), net	497,000	(4,897,000)	434,000
(Loss) income before income taxes	(66,263,000)	20,316,000	41,033,000
Provision for income taxes	7,974,000	8,189,000	7,552,000
Net (loss) income	$ (74,237,000)	$ 12,127,000	$ 33,481,000
Net (loss) income per common share:
Basic	$ (5.96)	$ 0.98	$ 2.70
Diluted	$ (5.96)	$ 0.96	$ 2.66
Weighted average shares outstanding:
Basic	12,456	12,402	12,407
Diluted	12,456	12,615	12,606
Dividends declared and paid per share	$ 0.40	$ 0.40	$ 0.40