Contractual Maturities of Money Market Funds and Marketable Securities (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Due in 1 year or less	$ 23,089,499
Due in 1 to 2 years	3,553,909
Amortized Cost	26,643,408	34,017,451
Due in 1 year or less	23,090,209
Due in 1 to 2 years	3,550,210
Fair Value	$ 26,640,419us-gaap_AvailableForSaleSecurities	$ 34,012,152us-gaap_AvailableForSaleSecurities

Available for Sale Securities, Debt Maturities, after One Through Two Years, Fair Value

No definition available.

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- Definition

Available for sale Securities, Debt Maturities, One Through Two Years, Amortized Cost

+ References

No definition available.

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- Definition

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

+ References

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-Publisher FASB

-Name Accounting Standards Codification

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- Definition

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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- Definition

Amount after adjustments of available-for-sale debt securities at cost, maturing in the next fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings less cumulative-effect adjustments, and fair value hedge accounting adjustments. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

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-Subparagraph (SX 210.5-02.2)

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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