For an unclassified balance sheet, this item represents investments in debt securities which are categorized as held-to-maturity. The held-to-maturity category is for those securities that the entity has the positive intent and ability to hold until maturity.

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+ Details

Fair Value Measurement of Assets and Liabilities (Details Textual) (USD $)	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2012 Auction Rate Securities [Member]	Mar. 31, 2011 Auction Rate Securities [Member]	Mar. 31, 2012 Collateralized Debt Obligations [Member]	Mar. 31, 2011 Collateralized Debt Obligations [Member]	Mar. 31, 2012 Structured investment vehicles [Member]	Mar. 31, 2011 Structured investment vehicles [Member]
Investment Holdings [Line Items]
Direct investments			$ 0	$ 0	$ 0	$ 0	$ 0	$ 0
Fair Value Measurement of Assets and Liabilities (Textual) [Abstract]
Short-term and long-term investments	77,040,200	72,019,726
Non-financial assets or liabilities measured at fair value	$ 0	$ 0