Stock-based Compensation (Tables)

6 Months Ended

Jun. 30, 2023

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Stock Option Activity and Related Information

A summary of stock option activity and related information as of June 30, 2023 is as follows:

	Number of Option Shares			Weighted Average Exercise Price
Outstanding at December 31, 2022		7,985,250		$	5.55
Granted		770,350			2.39
Exercised		—			—
Cancelled		(469,184	)		3.99
Outstanding at June 30, 2023		8,286,416		$	5.34
Exercisable at June 30, 2023		7,492,898		$	5.65

Summary of Stock-based Compensation Expense

The following table summarizes stock-based compensation expense for the three and six months ended June 30, 2023 and 2022, respectively:

	Three months ended				Six months ended
	June 30,				June 30,
	2023		2022		2023		2022
Research, development and patents	$	120,037	$	96,364	$	261,155	$	138,871
General and administrative		205,673		178,138		467,818		216,684
Total stock-based compensation expense	$	325,710	$	274,502	$	728,973	$	355,555

Schedule of Assumptions Used in Estimating Fair Value of Options Granted and Performance-Based Stock Options

The following table provides the assumptions used in the Black-Scholes valuation model used to estimate the fair value of options granted during the six months ended June 30, 2023 and 2022, and to estimate the fair value of performance-based stock options as of June 30, 2023 and 2022.

	Six months ended
	June 30, 2023	June 30, 2022
Stock Option assumptions:
Risk-free interest rate	3.59 - 4.13%	2.42 - 3.01%
Expected volatility of common stock	75.81 - 77.96%	75.13 - 78.45%
Dividend yield	0.00%	0.00%
Expected term (in years)	5.13 - 5.38	5.12 - 5.77