Income Taxes (Tables)

12 Months Ended

Dec. 31, 2016

	As of December 31,
	2016			2015
Deferred tax assets:
Net operating loss carryforwards	$	66,150,646		$	60,129,827
R&D credit carryforwards		9,729,673			9,465,900
Stock compensation		1,368,458			1,898,394
Intangibles		1,720,761			1,921,934
Temporary differences		132,475			801,002
Deferred tax assets before valuation allowance		79,102,014			74,217,057
Valuation allowance		(79,102,014	)		(74,217,057	)
Net deferred tax assets	$	—		$	—

				As of December 31, 2016
Generated		Expiration		U.S. Net Operating Loss Carryforwards		U.S. R&D Credit Carryforwards
	1998		2018	$	17,142,781	$	1,173,387
	1999		2019		—		130,359
	2000		2020		—		71,713
	2001		2021		—		39,128
	2002		2022		1,282,447		5,350
	2003		2023		337,714		2,905
	2004		2024		1,237,146		22,861
	2005		2025		2,999,083		218,332
	2006		2026		3,049,735		365,541
	2007		2027		2,842,078		342,898
	2008		2028		2,777,503		531,539
	2009		2029		13,727,950		596,843
	2010		2030		5,397,680		1,094,449
	2011		2031		1,875,665		1,950,744
	2012		2032		28,406,659		468,008
	2013		2033		37,450,522		681,772
	2014		2034		34,088,874		816,116
	2015		2035		25,073,846		492,732
	2016		2036		15,581,209		358,404
	Total carryforwards			$	193,270,891	$	9,363,081

	Years Ended December 31,
	2016						2015						2014
	Amount			%			Amount			%			Amount			%
Benefit at statutory rate	$	(4,864,851	)		(34.0	)%	$	(9,777,786	)		(34.0	)%	$	(12,147,068	)		(34.0	)%
Adjustments to valuation allowance		4,838,082			33.8	%		9,728,667			33.8	%		12,925,380			36.2	%
Adjustments to R&D credit carryforwards		(239,049	)		(1.6	)%		(612,087	)		(2.1	)%		(340,886	)		(1.0	)%
Disqualified debt interest		188,060			1.3	%		438,007			1.5	%		—			0.0	%
Permanent items and other		77,758			0.5	%		(212,852	)		(0.7	)%		(437,426	)		(1.2	)%
Benefit per financial statements	$	—					$	(436,051	)				$	—