Accrued Expenses and Other Current Liabilities (Narrative) (Details) - USD ($)			12 Months Ended
	Aug. 01, 2019	Aug. 01, 2018	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2018
Accrued Expenses And Other Current Liabilities [Line Items]
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201602Member	us-gaap:AccountingStandardsUpdate201409Member
Operating lease, right-of-use assets	$ 35,825,000		$ 30,033,000
Operating lease liabilities, current	568,000		$ 8,247,000
Minimum coverage period of product warranty from the date of shipment			1 year
Accrued warranty obligations			$ 15,200,000	$ 15,968,000	$ 11,738,000
Contract liabilities			(40,250,000)	(38,682,000)
Reclassification, Accrued Expenses and Other Current Liabilities
Accrued Expenses And Other Current Liabilities [Line Items]
Accrued expenses and other current liabilities	2,934,000
Short-term deferred rent	2,366,000
Operating lease, right-of-use assets	2,366,000
Estimated facility exit costs	568,000
Operating lease liabilities, current	$ 568,000
Reclassification, Accrued Warranty Obligations
Accrued Expenses And Other Current Liabilities [Line Items]
Accrued warranty obligations		$ (1,679,000)
TeleCommunication Systems, Inc. | TCS's 911 call handling software
Accrued Expenses And Other Current Liabilities [Line Items]
Accrued warranty obligations			$ 2,158,000	$ 3,999,000
Warranty Obligations | Reclassification, Accrued Warranty Obligations
Accrued Expenses And Other Current Liabilities [Line Items]
Contract liabilities		$ (1,679,000)