Note 3 - Short-term Investments Available for Sale (Details) - Short-Term Investment by Bond Maturities (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2009
Short-term investments
Short-term investments	$ 24,189,438	$ 37,200,576
Short-term investments	24,173,406us-gaap_AvailableForSaleSecurities	37,156,381us-gaap_AvailableForSaleSecurities	903,112us-gaap_AvailableForSaleSecurities
Short-term investment maturities
Short-term investments maturities	24,189,438	37,200,576
Short-term investments maturities	24,173,406	37,156,381
Certificate of Deposit [Member]
Short-term investments
Short-term investments	5,000,000	3,840,000
Short-term investments	4,996,568	3,835,083
Corporate Debt Securities [Member]
Short-term investments
Short-term investments	19,189,438	33,360,576
Short-term investments	19,176,838	33,321,298
Investment Maturing Within 3 Months [Member]
Short-term investment maturities
Short-term investments maturities	16,881,490	7,799,032
Short-term investments maturities	16,872,158	7,797,689
Investment Maturing Between 3 and 12 Months [Member]
Short-term investment maturities
Short-term investments maturities	7,307,948	29,401,544
Short-term investments maturities	$ 7,301,248	$ 29,358,692

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This item represents the cost of debt 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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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount of debt securities categorized neither as held-to-maturity nor trading.

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