Short-term Investments (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012
Schedule Of Available For Sale Securities [Line Items]
Short-term Investments, Amortized Cost	$ 19,914
Short-term Investments, Unrealized Gains	46
Short-term Investments, Unrealized Losses
Short-term Investments, Estimated Fair Value	19,960
Corporate bonds
Schedule Of Available For Sale Securities [Line Items]
Short-term Investments, Amortized Cost	11,072
Short-term Investments, Unrealized Gains	37
Short-term Investments, Unrealized Losses
Short-term Investments, Estimated Fair Value	11,109
Government bonds
Schedule Of Available For Sale Securities [Line Items]
Short-term Investments, Amortized Cost	8,842
Short-term Investments, Unrealized Gains	9
Short-term Investments, Unrealized Losses
Short-term Investments, Estimated Fair Value	$ 8,851