Cash, Cash Equivalents and Investments (Details 1) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Short-term investments
Short-term investments, Amortized Cost	$ 50,892	$ 1,830
Short-term investments, Gross Unrealized Gains	444	1,207
Short-term investments, Gross Unrealized Losses	(32)
Short-term investments, Fair Value	51,304	3,037
Commercial paper [Member]
Short-term investments
Short-term investments, Amortized Cost	1,497
Short-term investments, Gross Unrealized Gains	1
Short-term investments, Fair Value	1,498
Bank certificates of deposit [Member]
Short-term investments
Short-term investments, Amortized Cost	2,000
Short-term investments, Gross Unrealized Losses	(5)
Short-term investments, Fair Value	1,995
Corporate debt securities [Member]
Short-term investments
Short-term investments, Amortized Cost	26,101
Short-term investments, Gross Unrealized Gains	7
Short-term investments, Gross Unrealized Losses	(24)
Short-term investments, Fair Value	26,084
United States government agency securities [Member]
Short-term investments
Short-term investments, Amortized Cost	2,206
Short-term investments, Gross Unrealized Gains	2
Short-term investments, Fair Value	2,208
United States Treasury securities [Member]
Short-term investments
Short-term investments, Amortized Cost	17,258
Short-term investments, Gross Unrealized Losses	(3)
Short-term investments, Fair Value	17,255
Marketable equity securities [Member]
Short-term investments
Short-term investments, Amortized Cost	1,830	1,830
Short-term investments, Gross Unrealized Gains	434	1,207
Short-term investments, Gross Unrealized Losses
Short-term investments, Fair Value	$ 2,264	$ 3,037

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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This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

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- Definition

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

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