STOCK OPTIONS (Tables)

3 Months Ended

Mar. 31, 2022

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


	Three Months Ended March 31,
	2022		2021

Research and development expenses	$	176,218	$	887,077
General and administrative expenses		1,415,528		1,693,325
Total stock-based compensation	$	1,591,746	$	2,580,402

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 three months ended March 31, 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		4,636,015			0.47
Forfeited		(417,505	)		4.78
Expired		(277,925	)		4.75
Outstanding at March 31, 2022		19,266,690		$	3.17		7.27	$	10,371,031
Vested at March 31, 2022		9,906,454		$	4.57		5.40	$	2,635,020
Vested and expected to vest at March 31, 2022		17,633,030		$	3.36		7.07	$	8,581,750