Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2022

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Summary of fair value determined using the Black-Scholes option-pricing model

	June 30, 2022		December 31, 2021
	(Unaudited)
Exercise price		$0.51-$3.10		$6.44-$23.41
Risk-free rate of interest		1.80%-3.61%		0.69%-1.45%
Expected term (years)		5.5-6.5		5.25-6.5
Expected stock price volatility		94.9%-104.1%		80.0%-85.9%
Dividend yield		—		—

Schedule of share-based compensation arrangements by share-based payment award

The following table summarizes the Company’s employee and non-employee stock option activity under the Plan for the following periods:

				Weighted	Aggregate
		Weighted		average	intrinsic
	Number of	average		remaining	value
	shares	exercise price		term (years)	(in thousands)
Outstanding as of December 31, 2021	2,400,315	$	6.28	7.8	$	4,224
Granted	552,000		3.00	10.0		—
Forfeited	(45,367)		(14.05)	(9.1)		—
Outstanding as of March 31, 2022	2,906,948	$	5.54	8.0	$	1,006
Granted	350,000		0.52	10.0		—
Forfeited	(550,833)		(3.76)	—		—
Outstanding as of June 30, 2022	2,706,115	$	5.20	7.7	$	174
Options vested and exercisable as of June 30, 2022	1,361,446	$	4.83	6.4	$	145

Summary of recognition of stock-based compensation

The following table summarizes the Company’s recognition of stock-based compensation for the following periods (in thousands):

	Three months ended June 30,				Six months ended June 30,
	2022		2021		2022		2021
Stock-based compensation expense
General and administrative	$	768	$	4,095	$	1,884	$	4,439
Research and development		219		188		437		216
Total stock-based compensation expense	$	987	$	4,283	$	2,321	$	4,655

Substitute Options

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Summary of fair value determined using the Black-Scholes option-pricing model

	Original Options		Substitute Options
Strike price		$1.00-$72.30		$0.20-$14.58
Volatility rate		80.0%		80.0%
Risk-free rate		0.07%-0.79%		0.07%-0.79%
Expected term		0.18-5.99		0.18-5.99
Dividend yield		—		—