Income Taxes (Tables)

12 Months Ended

Dec. 31, 2016

Reconciliation of Federal Statutory Rate

The Company’s effective income tax rate differs from the amount computed by applying the federal statutory income tax rate to loss before income taxes as follows:



	2016		2015		2014
Income tax benefit at the federal statutory rate	(34	)%	(34	)%	(34	)%
State income tax benefit, net of federal tax benefit	(6	)%	(6	)%	(6	)%
Change in fair value of warrant liability	7	%	8	%	2	%
Change in valuation allowance for deferred tax assets	35	%	32	%	38	%
Other	(2	)%	—	%	—	%
Total	—	%	—	%	—	%

Schedule of Deferred Tax Assets

Deferred taxes consisted of the following:



	December 31, 2016			December 31, 2015			December 31, 2014
Net operating loss carryforwards	$	27,267,545		$	20,091,036		$	16,302,000
Stock-based compensation	3,090,903			2,599,308			2,191,000
Less valuation allowance	(30,358,448		)	(22,690,344		)	(18,493,000		)
Net deferred tax asset	$	—		$	—		$	—