Accrued Expenses and Other Current Liabilities (Details) - USD ($)	Oct. 31, 2017	Jul. 31, 2017	Oct. 31, 2016	Jul. 31, 2016
Business Acquisition [Line Items]
Accrued wages and benefits	$ 20,436,000	$ 19,622,000
Accrued warranty obligations	13,001,000	17,617,000	$ 14,984,000	$ 15,362,000
Accrued contract costs	8,363,000	8,644,000
Accrued legal costs	7,983,000	8,402,000
Accrued commissions and royalties	2,540,000	3,600,000
Other	10,780,000	10,725,000
Accrued expenses and other current liabilities	63,103,000	68,610,000
TeleCommunication Systems Inc. | Pre-Acquisition Contingencies Related to TCS Intellectual Property
Business Acquisition [Line Items]
Accrued legal costs	$ 3,739,000	$ 4,120,000