Condensed Consolidated Statements of Cash Flows - USD ($)	6 Months Ended
	Jan. 31, 2019	Jan. 31, 2018
Cash flows from operating activities:
Net income	$ 11,294,000	$ 14,101,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of property, plant and equipment	5,700,000	6,663,000
Amortization of intangible assets with finite lives	8,577,000	10,537,000
Amortization of stock-based compensation	2,237,000	1,827,000
Amortization of deferred financing costs	732,000	1,098,000
Write-off of deferred financing costs	3,217,000	0
Estimated contract settlement costs	3,886,000	0
Settlement of intellectual property litigation	(3,204,000)	0
Loss on disposal of property, plant and equipment	40,000	0
Provision for allowance for doubtful accounts	487,000	577,000
Provision for excess and obsolete inventory	1,749,000	2,433,000
Deferred income tax expense (benefit)	2,594,000	(11,218,000)
Changes in assets and liabilities:
Accounts receivable	3,229,000	5,801,000
Inventories	(14,068,000)	(13,537,000)
Prepaid expenses and other current assets	1,568,000	1,745,000
Other assets	107,000	(257,000)
Accounts payable	(14,693,000)	(2,259,000)
Accrued expenses and other current liabilities	3,282,000	(5,146,000)
Contract liabilities	(857,000)	235,000
Other liabilities, non-current	275,000	(242,000)
Interest payable	177,000	(199,000)
Income taxes payable	(3,291,000)	(2,982,000)
Net cash provided by operating activities	13,038,000	9,177,000
Cash flows from investing activities:
Purchases of property, plant and equipment	(4,181,000)	(2,836,000)
Net cash used in investing activities	(4,181,000)	(2,836,000)
Cash flows from financing activities:
Net borrowings of long-term debt under Credit Facility	174,500,000	0
Net (payments) borrowings under Revolving Loan portion of Prior Credit Facility	(48,603,000)	9,400,000
Repayment of debt under Term Loan portion of Prior Credit Facility	(120,121,000)	(10,354,000)
Remittance of employees' statutory tax withholdings for stock awards	(5,021,000)	(998,000)
Cash dividends paid	(4,998,000)	(4,821,000)
Payment of deferred financing costs	(1,808,000)	0
Repayment of principal amounts under capital lease and other obligations	(863,000)	(1,337,000)
Proceeds from issuance of employee stock purchase plan shares	476,000	397,000
Payment of shelf registration costs	(80,000)	0
Proceeds from exercises of stock options	174,000	0
Net cash used in financing activities	(6,344,000)	(7,713,000)
Net increase (decrease) in cash and cash equivalents	2,513,000	(1,372,000)
Cash and cash equivalents at beginning of period	43,484,000	41,844,000
Cash and cash equivalents at end of period	45,997,000	40,472,000
Cash paid during the period for:
Interest	3,844,000	3,977,000
Income taxes, net	941,000	108,000
Non-cash investing and financing activities:
Cash dividends declared but unpaid (including dividend equivalents)	2,548,000	2,506,000
Accrued additions to property, plant and equipment	963,000	1,102,000
Accrued deferred financing costs	4,000	0
Accrued shelf registration costs	68,000	0
Issuance (forfeiture) of restricted stock	$ 1,000	$ (1,000)