Cash and Cash Equivalents and Short-term Investments (Details 4) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012
Debt securities:
Due in one year or less	$ 206
Due after one year through five years	19,225
Due in more than five years	6,536
Total debt securities	$ 25,967

Amount of debt securities categorized neither as held-to-maturity nor trading.

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