Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net (loss) income	$ (74,237,000)	$ 12,127,000	$ 33,481,000
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for (benefit from) deferred income taxes	5,070,000	(457,000)	4,404,000
Depreciation and amortization	24,625,000	22,952,000	23,307,000
Asset impairment charges	84,510,000	0	0
Non-cash restructuring charges	1,882,000
Share-based compensation expense	9,430,000	8,864,000	10,938,000
Amortization of demo equipment	2,603,000	2,914,000	2,646,000
Provision for excess and obsolescence inventory	9,246,000	1,354,000	2,391,000
Excess tax benefit from share-based compensation	(159,000)	(395,000)	(1,134,000)
Change in fair value of contingent consideration	(10,239,000)	141,000	(62,000)
Provision for doubtful accounts, net of recovery	(318,000)	(151,000)	420,000
(Gain) loss on sale of property, plant and equipment	(223,000)	110,000	(115,000)
Net changes in operating assets and liabilities:
Accounts receivable	35,807,000	6,073,000	(16,050,000)
Inventory	(683,000)	(21,624,000)	(14,714,000)
Prepaid expenses and other assets	793,000	(2,275,000)	(387,000)
Accounts payable	(1,913,000)	(2,233,000)	(7,281,000)
Accrued liabilities	(3,362,000)	(1,367,000)	4,755,000
Deferred revenue	(624,000)	(126,000)	(5,433,000)
Customer deposits	55,000	(516,000)	965,000
Accrued income taxes and income taxes receivable	(5,144,000)	6,832,000	(1,895,000)
Other liabilities	(1,893,000)	764,000	2,474,000
Cash paid for contingent consideration	(100,000)
NET CASH PROVIDED BY OPERATING ACTIVITIES	75,126,000	32,987,000	38,710,000
CASH FLOWS FROM INVESTING ACTIVITIES:
Additions to property, plant, and equipment	(9,116,000)	(13,121,000)	(9,954,000)
Purchases of marketable securities	(44,968,000)
Acquisition of businesses, net of cash acquired		(8,424,000)	(1,600,000)
Proceeds from the sale of property, plant, and equipment	57,000	106,000	559,000
NET CASH USED IN INVESTING ACTIVITIES	(54,027,000)	(21,439,000)	(10,995,000)
CASH FLOWS FROM FINANCING ACTIVITIES:
Issuance of stock pursuant to exercise of stock options, employee stock purchase plan, restricted stock plans, and non-employee director stock plan	3,362,000	4,724,000	7,893,000
Repurchase of common stock	(4,410,000)	(13,698,000)	(13,872,000)
Shares repurchased for taxes for vested employee restricted stock grants	(2,203,000)	(2,724,000)	(2,832,000)
Excess tax benefit from share-based compensation	159,000	395,000	1,134,000
Dividends paid to shareholders	(5,002,000)	(4,964,000)	(5,111,000)
Cash paid for financing cost		(500,000)
Contingent consideration paid for business acquisitions	(1,900,000)
NET CASH USED IN FINANCING ACTIVITIES	(9,994,000)	(16,767,000)	(12,788,000)
EFFECT OF EXCHANGE RATE CHANGES ON CASH	(504,000)	116,000	(5,667,000)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	10,601,000	(5,103,000)	9,260,000
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	118,697,000	123,800,000	114,540,000
CASH AND CASH EQUIVALENTS, END OF PERIOD	129,298,000	118,697,000	123,800,000
Supplemental disclosures of cash flow information:
Income taxes paid (refund), net	7,533,000	(1,494,000)	4,996,000
Non-cash transfer of demonstration inventory to fixed asset	5,172,000	4,237,000
Fixed asset additions in accounts payable and accrued liabilities	$ 588,000	$ 790,000	$ 596,000