STOCK OPTIONS (Tables)

6 Months Ended

Jun. 30, 2022

Stock-based compensation expense was classified in the consolidated statements of operations and comprehensive loss as follows:


	Three Months Ended June 30,				Six Months Ended June 30,
	2022		2021		2022		2021

Research and development expenses	$	147,626	$	913,003	$	323,844	$	1,800,080
General and administrative expenses		1,365,463		1,594,269		2,780,991		3,287,594
Total stock-based compensation	$	1,513,089	$	2,507,272	$	3,104,835	$	5,087,674

The weighted average assumptions used principally in determining the fair value of options granted to employees were as follows:

A summary of option activity for the six months ended June 30, 2022 and is presented below:


Options	Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term in Years		Aggregate Intrinsic Value
Outstanding at December 31, 2021		15,326,105		$	4.06
Granted		5,086,303			0.46
Forfeited		(842,234	)		3.66
Expired		(277,925	)		4.75
Outstanding at June 30, 2022		19,292,249		$	3.12		7.06	$	10,822,865
Vested at June 30, 2022		10,412,743		$	4.48		5.32	$	2,706,655
Vested and expected to vest at June 30, 2022		17,904,934		$	3.28		6.88	$	9,268,907