Note 4 - Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2012

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

	Total Fair Value on the Balance Sheet		Quoted Prices In Active Markets For Identical Assets /Liabilities (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
As of December 31, 2012
Short-term investments available for sale
Bonds – corporate issuances	$	8,037,620	$	8,037,620	$	−	$	−
As of December 31, 2011
Short-term investments available for sale
Bonds – corporate issuances	$	10,157,160	$	10,157,160	$	−	$	−
Equity Securities		–		–		–		–
Liabilities:
As of December 31, 2012
Common stock warrant liability	$	4,283,932	$	−	$	−	$	4,283,932
As of December 31, 2011
Common stock warrant liability	$	166,398	$	−	$	−	$	166,398

Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]

	Equity  Securities			Warrant Liability
Beginning balance, January 1, 2010	$	58,929		$	(821,891	)
Unrealized (loss) gain included in other comprehensive (loss) income		(73,378	)		–
Gain from valuation of common stock warrant liability included in net loss		–			573,760
Ending balance, December 31, 2010		(14,449	)		(248,131	)
Unrealized gain (loss) included in other comprehensive (loss) income		(93,924	)		–
Gain from valuation of common stock warrant liability included in net loss		–			81,733
Ending balance, December 31, 2011	$	(108,373	)	$	(166,398	)
Unrealized gain (loss) included in other comprehensive (loss) income		108,373			–
Loss from valuation of common stock warrant liability included in net loss		–			(4,117,534	)
Ending balance, December 31, 2012	$	–		$	(4,283,932	)