Income Taxes (Tables)

12 Months Ended

Dec. 31, 2014

Current Income Tax Expense Benefit Attributable to Continuing Operations

Current income tax expense (benefit) attributable to continuing operations consists of the following for the years ended December 31, 2014, 2013, and 2012.


	Years Ended December 31,
	2014		2013		2012
Federal		—		—		—
State		—		—		—
Total		—		—		—

Effective Income Tax Rate Differs from the Statutory Federal Income Tax Rate

The Company’s effective income tax rate differs from the statutory federal income tax rate as follows for the years ended December 31, 2014, 2013, and 2012.

	Years Ended December 31,
	2014			2013			2012
Federal tax provision (benefit) rate		(34.0	)%		(34.0	)%		(34.0	)%
State tax provision, net of federal provision		(7.0	)		(4.8	)		(3.5	)
Permanent items		(3.6	)		3.4			0.8
Federal research and development credits		(1.0	)		(1.7	)		—
Expiration of tax attribute		10.9			—			—
Valuation allowance		34.7			37.1			36.7
Effective income tax rate		—	%		—	%		—	%

Deferred Tax Assets

The Company’s deferred tax assets consist of the following:

	December 31,
	2014			2013
Deferred tax assets:
Net operating loss carryforwards	$	35,449,695		$	32,253,602
Research and development credit carryforwards		1,855,586			1,735,265
Accrued expenses		657,132			493,075
Stock-based compensation		590,006			565,077
Other		13,506			1,061,212
Total gross deferred tax assets		38,565,925			36,108,231
Valuation allowance		(38,565,925	)		(36,108,231	)
Net deferred tax assets	$	—		$	—