Inventories - Inventory Valuation (Detail) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2018	Aug. 31, 2017	Aug. 31, 2016
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	$ 4,136
Balance at end of period	5,614	$ 4,136
Inventory Valuation Reserve
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	4,136	3,257	$ 2,679
Charge to cost of revenue	4,023	2,781	2,422
Disposition of inventory	(2,455)	(2,003)	(1,792)
Currency translation effect	(90)	101	(52)
Balance at end of period	$ 5,614	$ 4,136	$ 3,257