Other Balance Sheet Information Summary of Account Receivable (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013
Valuation and Qualifying Accounts Disclosure [Line Items]
Accounts receivable	$ 76,800	$ 78,460
Accounts receivable, net	75,529	77,483
Allowance for Doubtful Accounts
Valuation and Qualifying Accounts Disclosure [Line Items]
Less allowances	(1,131)	(863)
Allowance for Sales Returns
Valuation and Qualifying Accounts Disclosure [Line Items]
Less allowances	$ (140)	$ (114)