Short-term Investments (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014
Schedule Of Available For Sale Securities [Line Items]
Short-term Investments, Amortized Cost	$ 19,697	$ 19,900
Short-term Investments, Unrealized Losses	(42)	(39)
Short-term Investments, Estimated Fair Value	19,655	19,861
Corporate
Schedule Of Available For Sale Securities [Line Items]
Short-term Investments, Amortized Cost	14,977	14,262
Short-term Investments, Unrealized Losses	(35)	(27)
Short-term Investments, Estimated Fair Value	14,942	14,235
Government
Schedule Of Available For Sale Securities [Line Items]
Short-term Investments, Amortized Cost	4,720	5,638
Short-term Investments, Unrealized Losses	(7)	(12)
Short-term Investments, Estimated Fair Value	$ 4,713	$ 5,626