Marketable Securities (Details) (USD $)	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Marketable Securities
Other than temporary impairment	$ 0	$ 0
Maturity period of marketable securities (in years)	1 year
Gross realized gains or losses	0	0
Amortized cost	3,502,410		5,705,996
Gross Unrealized Holding Gains	8,778		13,741
Gross Unrealized Holding Losses			(30)
Fair Value	3,511,188		5,719,707
Certificates of deposit
Marketable Securities
Amortized cost	2,557,996		2,802,993
Gross Unrealized Holding Gains	5,499		8,684
Fair Value	2,563,495		2,811,677
Municipal bonds
Marketable Securities
Amortized cost	944,414		2,903,003
Gross Unrealized Holding Gains	3,279		5,057
Gross Unrealized Holding Losses			(30)
Fair Value	$ 947,693		$ 2,908,030

This item represents the aggregate fair value of investments in debt securities as of the balance sheet date and which are categorized as held-to-maturity.

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This item represents the gain (loss) realized on the sale of held-to-maturity securities disposed of during the period. Additionally, this item may include, if not separately presented, any losses recognized for other than temporary impairments (OTTI) of the subject investments in debt securities which are being or have been recognized in earnings during the period.

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- Definition

As of the balance sheet date, the excess of fair value over carrying value (amortized cost) of a debt security categorized as held-to-maturity, exclusive of dividend or interest income recognized but not yet received and exclusive of any write-downs for other-than-temporary impairment. Such item represents the gross unrecognized holding gain.

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- Definition

As of the balance sheet date, the excess of carrying value (amortized cost) over fair value of a debt security categorized as held-to-maturity, exclusive of dividend or interest income recognized but not yet received and exclusive of any write-downs for other-than-temporary impairment. Such item represents the gross unrecognized holding loss.

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- Definition

The amount by which the fair value of an investment in debt securities categorized as Held-to-maturity is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

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