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Summary of Significant Accounting and Reporting Policies (Narrative) (Details)		3 Months Ended												12 Months Ended
	Aug. 01, 2019	Jul. 31, 2019 USD ($)	Apr. 30, 2019 USD ($)	Jan. 31, 2019 USD ($)	Oct. 31, 2018 USD ($)	Jul. 31, 2018 USD ($)	Apr. 30, 2018 USD ($)	Jan. 31, 2018 USD ($)	Oct. 31, 2017 USD ($)	Jul. 31, 2017 USD ($)	Apr. 30, 2017 USD ($)	Jan. 31, 2017 USD ($)	Oct. 31, 2016 USD ($)	Jul. 31, 2019 USD ($) operating_segment	Jul. 31, 2018 USD ($)	Jul. 31, 2017 USD ($)	Jul. 31, 2016 USD ($)
Accounting Policies [Abstract]
Number of reportable segments \| operating_segment														2
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales		$ 176,372,000	$ 170,448,000	$ 164,133,000	$ 160,844,000	$ 167,435,000	$ 147,854,000	$ 133,731,000	$ 121,569,000	$ 147,762,000	$ 127,792,000	$ 139,028,000	$ 135,786,000	$ 671,797,000	$ 570,589,000	$ 550,368,000
Contract assets, increase from business combinations														3,331,000
Contract liabilities, increase from business combinations														5,411,000
Revenue recognized, included in contract liabilities in prior period														33,139,000
Cash and cash equivalents		$ 45,576,000				$ 43,484,000				$ 41,844,000				45,576,000	43,484,000	41,844,000	$ 66,805,000
Research and development expenses reimbursed by customers														$ 14,679,000	$ 16,924,000	$ 27,050,000
Measurement of uncertain tax position, percentage that likelihood of tax benefit being realized upon ultimate settlement must be greater than														50.00%
Non-current portion of capital lease obligations, blended interest rate		7.00%												7.00%
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use asset and lease liability, percentage of total assets	4.00%
International
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales														$ 170,607,000
Customer Concentration Risk \| Net sales \| Verizon Communications Inc.
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Concentration risk, percentage														10.00%	10.00%
Geographic Concentration Risk \| Net sales
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Concentration risk, percentage														100.00%	100.00%	100.00%
Geographic Concentration Risk \| Net sales \| International
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Concentration risk, percentage														25.40%	25.60%	28.40%
Net sales														$ 170,607,000	$ 145,784,000	$ 156,483,000