Income Taxes - Schedule of Components of Deferred Income Taxes (Details) - USD ($)	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Net operating loss carryforwards	$ 41,114,624	$ 40,156,864
Stock-based compensation	2,207,465	2,207,465
Research and development credit carryovers	2,791,710	2,591,539
Contribution carryovers	10,062	10,715
Accrued liabilities	490,467
Gross deferred tax assets	46,614,328	44,966,584
Intangible assets	(235,013)	(410,410)
Prepaid expenses	(90,881)
Other	(29,545)	(21,496)
Gross deferred tax liabilities	(355,439)	(431,906)
Valuation allowance	(46,258,889)	(44,534,678)
Deferred tax asset, net of valuation allowance
Change in valuation allowance	$ (1,724,211)	$ 14,750,866

Amount of deferred tax liability attributable to taxable temporary differences.

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