Fair Value of Financial Instruments (Details 4) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Fair Value of Financial Instruments
Corporate debt securities, Amortized Cost	$ 50,581	$ 57,967
Corporate debt securities, Gross Unrealized Gains	14	33
Corporate debt securities, Gross Unrealized Losses	(49)	(33)
Corporate debt securities, Fair Value	50,546	57,967
Contractual maturities of the unrestricted marketable securities held
Less Than 1 Year	34,783
1-5 years	15,763
Corporate debt securities, Fair Value	$ 50,546	$ 57,967

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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Fair value of available-for-sale debt securities maturing in the second fiscal year through the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Fair value of available-for-sale debt securities maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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