Stock Purchase Warrants (Tables)

6 Months Ended

Jun. 30, 2017

The assumptions used by the Company are summarized in the following table:

	Series A									Series B
	June 30, 2017			December 31, 2016			Issuance Date			June 30, 2017			December 31, 2016			Issuance Date
Closing stock price	$	0.57		$	0.76		$	0.89		$	0.57		$	0.76		$	0.89
Expected dividends		0	%		0	%		0	%		0	%		0	%		0	%
Expected volatility		95	%		85	%		85	%		75	%		90	%		85	%
Risk free interest rate		1.62	%		1.67	%		1.58	%		1.14	%		0.85	%		0.81	%
Expected life of warrant (years)		3.4			3.9			4.0			0.5			1.0			1.1

The assumptions used by the Company are summarized in the following table:

	June 30, 2017			December 31, 2016			Issuance Date
Closing stock price	$	0.57		$	0.76		$	1.75
Expected dividends		0	%		0	%		0	%
Expected volatility		0.90	%		95	%		95	%
Risk free interest rate		1.43	%		1.41	%		1.39	%
Expected life of warrant (years)		2.30			2.79			5.0

The following table summarizes the estimated fair value of the warrant liability (in thousands):

Balance at December 31, 2016	$	14,821
Change in fair value of warrant liability		(7,249	)
Balance at June 30, 2017	$	7,573

A summary of warrant activity for the Company for the six months ended June 30, 2017 and for the year ended December 31, 2016 is as follows:

	Number of Warrants			Weighted Average Exercise Price

Balance at December 31, 2015		7,908,899		$	1.79
Granted		50,000,000			1.58
Exercised		-			-
Forfeited		(567,257	)		2.35
Balance at December 31, 2016		57,341,642			1.60
Granted		-			-
Exercised		-			-
Forfeited		-			-
Balance at June 30, 2017		57,341,642		$	1.60

A summary of all outstanding and exercisable warrants as of June 30, 2017 is as follows:

Exercise Price		Warrants Outstanding		Warrants Exercisable		Weighted Average Remaining Contractual Life (years)
$	1.43		25,000,000		25,000,000	3.39
$	1.60		311,834		311,834	0.32
$	1.72		25,000,000		25,000,000	0.50
$	1.75		7,029,808		7,029,808	2.28
$	1.60		57,341,642		57,341,642	1.98