Note 3 - Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2014

Fair Value Disclosures [Abstract]

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

	Quoted Prices in Active Markets for Identical Items (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
March 31, 2014
Assets
Money market	$	2,007,240	$	—	$	—	$	2,007,240
Total assets	$	2,007,240	$	—	$	—	$	2,007,240
Liabilities
Warrants to purchase common stock	$	—	$	—	$	1,000,993		1,000,993
Total liabilities	$	—	$	—	$	1,000,993		1,000,993
December 31, 2013
Assets
Money market	$	3,206,079	$	—	$	—	$	3,206,079
Total assets	$	3,206,079	$	—	$	—	$	3,206,079
Liabilities
Warrants to purchase common stock	$	—	$	—	$	819,930	$	819,930
Total liabilities	$	—	$	—	$	819,930	$	819,930

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

	Convertible Common Stock Warrant Liability
Balance as of December 31, 2013	$	819,930
Settlements		(174,891	)
Changes in estimated fair value		355,954
Balance as of March 31, 2014	$	1,000,993