Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2020

Stock-Based Compensation [Abstract]

Stock-Based Compensation Expense

The following table summarizes the components of stock-based compensation expense in the consolidated statements of operations and comprehensive loss for the years ended December 31, 2020 and 2019:

	Year Ended December 31,
	2020		2019
Research and development	$	229,977	$	550,605
General and administrative		202,344		2,588,448
Total	$	432,321	$	3,139,053

Stock Option Activity

The following table summarizes the stock option activity for the Company’ stock option plans for the year ended December 31, 2020:

	Number of Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Life in Years		Aggregate Intrinsic Value
Balance at January 1, 2020		1,421,797		$	15.95		6.99
Granted		331,407		$	1.46
Exercised		–		$	–
Forfeited		(84,583	)	$	41.19
Expired		(17,724	)	$	4.69
Options outstanding at December 31, 2020		1,650,897		$	11.87		7.03	$	226,731
Vested and expected to vest at December 31, 2020		1,650,897		$	11.87		7.03	$	226,731
Exercisable at December 31, 2020		1,090,493		$	16.29		5.47	$	–

Assumptions Used to Value Options and Warrants Granted

The fair value of options granted during the year ended December 31, 2020 was estimated using the Black-Scholes option valuation model utilizing the following assumptions:

	Year Ended December 31,
	2020			2019
	Weighted Average
Volatility		97.50	%		88.70	%
Risk-Free Interest Rate		0.39	%		2.31	%
Expected Term in Years		6.04			5.54
Dividend Rate		-			-
Fair Value of Option on Grant Date	$	1.14		$	5.67