Stockholders' (Deficit) Equity (Tables)

6 Months Ended

Jun. 30, 2022

Equity [Abstract]

Summary of Option Activity under 2018 Plan, 2013 Plan and 2010 Plan

A summary of option activity under the 2018 Plan, 2013 Plan, and 2010 Plan for the six months ended June 30, 2022, is as follows:

Year-to-Date Activity	Number of Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value (in Millions)
Options outstanding at December 31, 2021		1,954,975		$	8.16		7.8
Granted		958,000		$	2.33
Cancelled/forfeited		(62,188	)	$	4.12
Options outstanding at June 30, 2022		2,850,787		$	6.29		8.0	$	—
Options exercisable at June 30, 2022		1,322,180		$	9.80		6.6	$	—

Summary of Stock-Based Compensation Expense

The fair value of shares vested during the three and six months ending June 30, 2022 was $0.4 million and $1.5 million, respectively. The fair value of shares vested during the three and six months ending June 30, 2021 was $0.3 million and $1.2 million, respectively. The amount of stock-based compensation expense recorded to research and development expenses and to general and administrative expenses is detailed in table below:

	Three Months Ended June 30,				Six Months Ended June 30,
	2022		2021		2022		2021
Stock-based compensation
Research and development	$	158,880	$	176,534	$	299,320	$	344,580
General and administrative		301,897		418,129		635,554		809,519
Total stock-based compensation expense	$	460,777	$	594,663	$	934,874	$	1,154,099

Summary of Warrants Issued

	Six Months Ended June 30,
	2022				2021
	Number		Weighted Average Exercise Price		Number		Weighted Average Exercise Price
Granted during the period		150,000	$	2.46		—	$	—
Outstanding at end of the period		150,000	$	2.46		—	$	—
Exercisable at end of the period		150,000	$	2.46
Weighted average remaining life	6.8 years					—