Other Balance Sheet Information - Summary of Account Receivable (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Sep. 30, 2015
Valuation and Qualifying Accounts Disclosure [Line Items]
Accounts receivable	$ 103,396	$ 87,582
Accounts receivable, net	101,091	86,448
Allowance for Doubtful Accounts
Valuation and Qualifying Accounts Disclosure [Line Items]
Less allowances	(2,200)	(1,019)
Allowance for Sales Returns
Valuation and Qualifying Accounts Disclosure [Line Items]
Less allowances	$ (105)	$ (115)