Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2018	Apr. 30, 2017
Net revenue:
Product	$ 117,156	$ 120,791	$ 349,599	$ 371,373
Engineering	2,815	1,371	6,419	3,448
Total net revenue	119,971	122,162	356,018	374,821
Cost of sales:
Product	64,576	68,667	192,904	210,149
Engineering	2,466	1,334	5,554	3,180
Total cost of sales	67,042	70,001	198,458	213,329
Gross profit	52,929	52,161	157,560	161,492
Operating expenses:
Research and product development	15,285	14,900	45,927	46,962
Selling and marketing	13,530	16,356	39,131	51,894
General and administrative	16,824	10,377	40,864	27,978
Restructuring	(21)	2,080	710	2,379
Asset impairment charges		73,051		83,474
Total operating expenses	45,618	116,764	126,632	212,687
Income (loss) from operations	7,311	(64,603)	30,928	(51,195)
Other income (expense), net	328	57	1,504	(357)
Income (loss) before income taxes	7,639	(64,546)	32,432	(51,552)
Provision (benefit) for income taxes	529	(4,882)	13,115	(1,934)
Net income (loss)	$ 7,110	$ (59,664)	$ 19,317	$ (49,618)
Net income (loss) per common share:
Basic	$ 0.57	$ (4.78)	$ 1.55	$ (3.98)
Diluted	$ 0.56	$ (4.78)	$ 1.53	$ (3.98)
Weighted average shares outstanding:
Basic	12,503	12,486	12,489	12,457
Diluted	12,633	12,486	12,617	12,457
Dividends declared and paid per share	$ 0.10	$ 0.10	$ 0.30	$ 0.30