Impact of the Adoption on Consolidated Statement of Operations (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Oct. 31, 2018	Oct. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net revenue	$ 215,133	$ 102,522
Cost of revenue	176,933	93,448
Gross profit	38,200	9,074
Loss before income taxes	(6,254)	(4,351)
Net loss	(7,365)	(5,237)
Net loss attributable to common stockholders	$ (7,901)	$ (5,237)
Basic and diluted net loss per share attributable to common stockholders:	$ (0.13)	$ (0.09)
Accounting Standards Update 2014-09 | Calculated under Revenue Guidance in Effect before Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net revenue	$ 214,208
Cost of revenue	176,743
Gross profit	37,465
Loss before income taxes	(6,989)
Net loss	(8,100)
Net loss attributable to common stockholders	$ (8,636)
Basic and diluted net loss per share attributable to common stockholders:	$ (0.14)
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net revenue	$ 925
Cost of revenue	190
Gross profit	735
Loss before income taxes	735
Net loss	735
Net loss attributable to common stockholders	$ 735
Basic and diluted net loss per share attributable to common stockholders:	$ 0.01