Note 2 - Fair Value Measurements

6 Months Ended

Jun. 30, 2015

Fair Value Disclosures [Abstract]

Fair Value Disclosures [Text Block]

Note 2—Fair Value Measurements

Accounting Standards Codification (“ASC”) Topic 820, Fair Value Measurement (“ASC 820”), establishes a fair value hierarchy for instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and the Company's own assumptions (unobservable inputs). Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company's assumptions about the inputs that market participants would use in pricing the asset or liability, and are developed based on the best information available in the circumstances.

ASC 820 identifies fair value as the exchange price, or exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As a basis for considering market participant assumptions in fair value measurements, ASC 820 establishes a three-tier fair value hierarchy that distinguishes among the following:

Level 1—Valuations based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access.

Level 2—Valuations based on quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active and models for which all significant inputs are observable, either directly or indirectly.

Level 3—Valuations based on inputs that are unobservable and significant to the overall fair value measurement.

To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument's level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement.  

 Recurring Fair Value Measurements

Items measured at fair value on a recurring basis include money market mutual funds and warrants to purchase common stock. During the periods presented, the Company has not changed the manner in which it values assets and liabilities that are measured at fair value using Level 3 inputs. The following fair value hierarchy table presents information about each major category of the Company's financial assets and liabilities measured at fair value on a recurring basis:

	Quoted Prices in Active Markets for Identical Items		Significant Other Observable Inputs		Significant Unobservable Inputs
	(Level 1)		(Level 2)		(Level 3)		Total
June 30, 2015
Assets
Money market	$	10,021,694	$	-	$	-	$	10,021,694
Total assets	$	10,021,694	$	-	$	-	$	10,021,694
Liabilities
Warrants to purchase common stock	$	-	$	-	$	457,850	$	457,850
Total Liabilities	$	-	$	-	$	457,850	$	457,850
December 31, 2014
Assets
Money market	$	10,014,243	$	-	$	-	$	10,014,243
Total assets	$	10,014,243	$	-	$	-	$	10,014,243
Liabilities
Warrants to purchase common stock	$	-	$	-	$	418,530	$	418,530
Total Liabilities	$	-	$	-	$	418,530	$	418,530

The following table sets forth a summary of changes in the fair value of the Company's Common Stock warrant liability, which represents a recurring measurement that is classified within Level 3 of the fair value hierarchy, wherein fair value is estimated using significant unobservable inputs:

	Convertible Common Stock Warrant Liability
Balance as of December 31, 2014	$	418,530
Changes in estimated fair value		39,320
Balance as of June 30, 2015	$	457,850

The Company recognizes transfers between levels of the fair value hierarchy as of the end of the reporting period. There were no transfers within the hierarchy during the six months ended June 30, 2015 and the year ended December 31, 2014.

The fair value of the warrants on the date of issuance and on each re-measurement date of those warrants classified as liabilities is estimated using the Black-Scholes option pricing model using the following assumptions: contractual life according to the remaining terms of the warrants, no dividend yield, weighted average risk-free interest rate of 2.35% at June 30, 2015 and weighted average volatility of 83.57%. For this liability, the Company developed its own assumptions that do not have observable inputs or available market data to support the fair value. This method of valuation involves using inputs such as the fair value of the Company's various classes of preferred stock, stock price volatility, the contractual term of the warrants, risk free interest rates and dividend yields. Due to the nature of these inputs, the valuation of the warrants is considered a Level 3 measurement. The warrant liability is recorded in other liabilities on the Company's condensed consolidated balance sheets. The warrant liability is marked-to-market each reporting period with the change in fair value recorded on the condensed consolidated statement of operations and comprehensive income (loss) until the warrants are exercised, expire or other facts and circumstances lead the warrant liability to be reclassified as an equity instrument.

Nonrecurring Fair Value Measurements

For assets and liabilities measured on a non-recurring basis during the year, accounting guidance requires quantitative disclosures about the fair value measurements separately for each major category. There were no remeasured assets or liabilities at fair value on a non-recurring basis for the six months ended June 30, 2015 and the year ended December 31, 2014.