Note 4 - Fair Value of Financial Instruments (Details) - Assets and Liabilities at Fair Value on a Recurring Basis (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2009
Short-term investments available for sale
Bonds – corporate issuances	$ 37,156,381		$ 903,112
As of December 31, 2013
Common stock warrant liability	3,026	4,283,932
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Short-term Investments [Member]
Short-term investments available for sale
Bonds – corporate issuances		8,037,620
Corporate Debt Securities [Member] | Short-term Investments [Member]
Short-term investments available for sale
Bonds – corporate issuances		8,037,620
Fair Value, Inputs, Level 1 [Member]
Short-term investments available for sale
Bonds – corporate issuances	37,156,381
Fair Value, Inputs, Level 3 [Member]
As of December 31, 2013
Common stock warrant liability	$ 3,026	$ 4,283,932