Other Balance Sheet Information - Allowance for Doubtful Accounts Activity (Detail) (Allowance for doubtful accounts, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Allowance for doubtful accounts
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 851	$ 617	$ 491
Provisions	48	367	0
Reversals of Bad Debt Expense	(143)	(130)	0
Write-offs and Adjustments	107	(3)	126
Balance at End of Period	$ 863	$ 851	$ 617