Accrued Expenses and Other Current Liabilities - Schedule (Details) - USD ($)	Oct. 31, 2019	Jul. 31, 2019	Oct. 31, 2017	Jul. 31, 2017
Accrued Liabilities, Current [Abstract]
Accrued wages and benefits	$ 21,261,000	$ 23,295,000
Accrued contract costs	13,725,000	15,007,000
Accrued warranty obligations	16,068,000	15,968,000	$ 9,982,000	$ 11,738,000
Accrued legal costs	2,781,000	2,835,000
Accrued commissions and royalties	4,587,000	5,114,000
Other	14,385,000	16,365,000
Accrued expenses and other current liabilities	$ 72,807,000	$ 78,584,000