Warrant Liability (Tables)

6 Months Ended

12 Months Ended

Jun. 30, 2015

Dec. 31, 2014

Warrant Liabilities [Abstract]

Summary of assumptions used in connection with the valuation of warrants issued

	December 31, 2014			Exercised during 2015			June 30, 2015
Number of shares underlying the warrants		4,723,357			1,679,286			3,044,071
Exercise price	$	0.61		$	0.61		$	0.61
Volatility		128	%		117% – 119	%		117	%
Risk-free interest rate		1.38	%		0.81% – 1.06	%		1.06	%
Expected dividend yield		0			0			0
Expected warrant life (years)		3.5			3.01 – 3.33			2.99
Stock Price	$	0.98		$	1.69 – 2.22		$	2.35

	Initial Measurement June 25, 2013			December 31, 2013			January 22, 2014			August 19, 2014			December 31, 2014
Number of shares underlying the warrants		5,416,851			5,309,438			5,309,438			5,059,438			4,723,357
Exercise price	$	1.65		$	1.65		$	1.65		$	1.65		$	0.61
Volatility		140	%		135	%		135	%		130	%		128	%
Risk-free interest rate		1.49	%		1.75	%		1.30	%		1.25	%		1.38	%
Expected dividend yield		0			0			0			0			0
Expected warrant life (years)		5.0			4.5			4.4			3.9			3.5
Stock Price	$	0.96		$	1.80		$	2.29		$	2.05		$	0.98

Summary of fair value measurements using significant unobservable inputs (Level 3)

	December 31,  2014		Decrease from Warrants Exercised in 2015			Increase in Fair Value		June 30, 2015
Warrant liability	$	3,789,562	$	(2,543,117	)	$	4,955,110	$	6,201,555

	December 31, 2013		Decrease from Warrants Exercised in 2014			Decrease in Fair Value			December 31, 2014
Warrant liability	$	8,281,247	$	(1,055,490	)	$	(3,436,195	)	$	3,789,562

	Initial Measurement June 25, 2013		Decrease from Warrants Exercised in 2013			Increase in Fair Value		December 31, 2013
Warrant liability	$	4,827,788	$	(201,311	)	$	3,654,770	$	8,281,247