Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2022

Stock-Based Compensation

Schedule of stock-based compensation expense

	Stock Option Grants				Restricted stock awards				Total
	2022		2021		2022		2021		2022			2021
Research and development	$	776,809	$	1,198,492	$	723,638	$	1,245,175	$	1,500,447	$	2,443,667
General and administrative		941,321		1,307,844		868,357		1,017,668		1,809,678		2,325,512
	$	1,718,130	$	2,506,336	$	1,591,995	$	2,262,843	$	3,310,125	$	4,769,179

Summary of stock option activity

		Weighted-		Weighted-
		Average		Average	Aggregate
	Number	Exercise		Contractual	Intrinsic
	of Shares	Price		Life (in Years)	Value
Outstanding as of December 31, 2021	5,224,913	$	8.74
Granted	1,136,728		2.17
Forfeited	(85,625)		10.97
Outstanding as of September 30, 2022	6,276,016		7.52	6.17	$	—
Exercisable as of September 30, 2022	4,303,603		9.58	5.00	$	—
Vested and expected to vest as of September 30, 2022	6,276,016	$	7.52

Schedule of weighted-average assumptions used to calculate fair values of stock options

	Nine months ended September 30,
	2022	2021
Weighted-average risk-free interest rate	2.02%	0.37%
Expected term of options (in years)	6.11	6.21
Expected stock price volatility	100.23%	95.60%
Expected dividend yield	0%	0%

Summary of restricted stock activity

		Weighted
		Average		Aggregate
		Grant Date		Intrinsic
	Shares	Fair Value		Value
Unvested as of December 31, 2021	989,822	$	3.62
Granted	1,398,154		2.17
Forfeited	(25,500)		2.41
Vested	(242,964)		3.60
Unvested as of September 30, 2022	2,119,512	$	2.86	$	1,551,483
Expected to vest as of September 30, 2022	1,566,512	$	2.85	$	1,146,687