Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2015

Fair values determined by Level 3 inputs are unobservable data points for the asset or liability, and include situations where there is little, if any, market activity for the asset or liability.

			Fair Value Measurements at September 30, 2015 Using
	September 30, 2015		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	$	5,028,053	$	5,028,053	$	—	$	—
Total	$	5,028,053	$	5,028,053	$	—		—

Liabilities:
Common stock warrants	$	890,105	$	—	$	—	$	890,105
Total	$	890,105	$	—	$	—	$	890,105

			Fair Value Measurements at December 31, 2014 Using
	December 31, 2014		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	$	4,107,478	$	4,107,478	$	—	$	—
Total	$	4,107,478	$	4,107,478	$	—	$	—

Liabilities:
Common stock warrants	$	5,307,332	$	—	$	—	$	5,307,332
Total	$	5,307,332	$	—	$	—	$	5,307,332

Black-Scholes Inputs to Warrant Liability Valuation

Based on the Black-Scholes model, the Company recorded a common stock warrants liability of $0.9 million at September 30, 2015. In May 2015, 1,571,744 warrants were repurchased by the Company. These warrants were adjusted to their fair value of $943,423 at the date of repurchase.

	Black-Scholes Inputs to Warrant Liability Valuation at September 30, 2015
Warrants:	Stock Price		Exercise Price		Expected Volatility			Risk-Free Interest			Expected Term	Dividends
2014 Offering	$	0.88	$	2.04		72.03	%		1.09	%	3yr 9mo	none
2013 Offering	$	0.88	$	2.00		72.80	%		0.82	%	2yr 8mo	none

	Black-Scholes Inputs to Warrant Liability Valuation at December 31, 2014
Warrants:	Stock Price		Exercise Price		Expected Volatility			Risk-Free Interest			Expected Term	Dividends
2014 Offering	$	1.95	$	2.04		71.11	%		1.51	%	4yr 6mo	none
2013 Offering	$	1.95	$	2.00		75.71	%		1.24	%	3yr 5mo	none

Fair Value, Liabilities Measured on Recurring Basis

The following table provides a summary of changes in the fair value of the Company’s Level 3 financial liabilities between December 31, 2014 and September 30, 2015.

	2014 Offering		2013 Offering		Total
Balance at December 31, 2014	$	4,233,729	$	1,073,603	$	5,307,332
Repurchase of warrants in conjunction with public offering		(943,423)		—		(943,423)
Change in fair value of warrant liability		(2,625,305)		(848,499)		(3,473,804)
Balance at September 30, 2015	$	665,001	$	225,104	$	890,105