Other Balance Sheet Information Summary of Account Receivable (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Sep. 30, 2013
Valuation and Qualifying Accounts Disclosure [Line Items]
Accounts receivable	$ 84,038	$ 78,460
Accounts receivable, net	82,792	77,483
Allowance for Doubtful Accounts
Valuation and Qualifying Accounts Disclosure [Line Items]
Less allowances	(1,100)	(863)
Allowance for Sales Returns
Valuation and Qualifying Accounts Disclosure [Line Items]
Less allowances	$ (146)	$ (114)