Investments (Details) (Short-term Investments [Member], USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Amortized cost and gross unrealized gains and losses on all securities
Amortized Cost	$ 14,552	$ 23,567
Gross Unrealized Gains		806
Gross Unrealized Losses	213	12
Fair Value	14,339	24,361
U.S. Treasury securities and agency [Member]
Amortized cost and gross unrealized gains and losses on all securities
Amortized Cost	2,506	3,509
Gross Unrealized Gains
Fair Value	2,506	3,509
FDIC Guaranteed Certificates of Deposit [Member]
Amortized cost and gross unrealized gains and losses on all securities
Amortized Cost	5,493	6,453
Gross Unrealized Gains
Gross Unrealized Losses	3	6
Fair Value	5,490	6,447
Common stock [Member]
Amortized cost and gross unrealized gains and losses on all securities
Amortized Cost	2,000	2,000
Gross Unrealized Gains		806
Gross Unrealized Losses	209
Fair Value	1,791	2,806
Corporate Notes and Bonds [Member]
Amortized cost and gross unrealized gains and losses on all securities
Amortized Cost	3,053	4,606
Gross Unrealized Gains
Gross Unrealized Losses	1	4
Fair Value	3,052	4,602
Commercial Paper [Member]
Amortized cost and gross unrealized gains and losses on all securities
Amortized Cost	1,500	6,999
Gross Unrealized Gains
Gross Unrealized Losses		2
Fair Value	$ 1,500	$ 6,997

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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