Stock Award Plan and Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Stock Option Activity for Employees and Non-Employees

Stock option activity for employees and non-employees for the nine months ended September 30, 2021 is as follows:

	Shares Issuable Pursuant to Stock Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Terms (years)		Total Intrinsic Value (in thousands)
Outstanding January 1, 2021		10,050,523		$	6.60		7.0	$	—
Granted		140,000		$	2.90
Exercised		—		$	—
Cancelled/Forfeited(1)		(8,396,056	)	$	6.94
Outstanding September 30, 2021		1,794,467		$	4.75		7.8	$	—
Exercisable September 30, 2021		913,530		$	5.99		6.6	$	—
Available for future grant		4,762,269

Summary of Assumptions Used in Black Scholes Model to Estimate Fair Value of Stock Options

The Company uses the Black-Scholes model to estimate the fair value of stock options granted. For stock options granted during the nine months ended September 30, 2021 and 2020, the Company utilized the following assumptions:

	Nine Months Ended September 30,
	2021		2020
Expected term (years)		5.50	5.50-6.25
Risk free interest rate	0.86%		0.37%-0.42%
Volatility	75%		68%-71%
Dividend yield	0%		0%
Weighted average grant date fair value per share of    common stock	$	1.83	$	1.62

Schedule of Stock-Based Compensation Expense Included in the Company's Consolidated Statements of Operations

The following table presents stock-based compensation expense included in the Company’s consolidated statements of operations:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Research and development	$	541,332	$	813,443	$	1,826,881	$	2,189,595
General and administrative		573,194		1,242,592		2,187,769		5,550,109
Total	$	1,114,526	$	2,056,035	$	4,014,650	$	7,739,704