Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Option Activity

A summary of option activity during the year ended December 31, 2021 is as follows:

	Number of Units Outstanding			Weighted Average Exercise Price per Unit		Weighted Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2020		7,737,095		$	4.22		9.3	$	16,374
Granted		3,953,160		$	7.31
Exercised		(789,225	)	$	1.83
Forfeited		(2,243,260	)	$	5.70
Expired		(67,359	)	$	5.18
Outstanding at December 31, 2021		8,590,411		$	5.48		8.8	$	6,196
Exercisable at December 31, 2021		2,538,244		$	4.78		8.6	$	2,634
Nonvested at December 31, 2021		6,052,167		$	5.77		9.0	$	3,590

Summary of Weighted-average Assumptions Used to Determine Grant Date Fair Value of Stock Options

The weighted-average assumptions that the Company used in Black-Scholes option pricing model to determine the grant date fair value of stock options granted to employees and non-employees were as follows:

	Year ended December 31,
	2021	2020
Expected term (in years)	5.8	6.3
Expected Volatility	73.1%	80.0%
Risk-free interest rate	1.1%	1.7%
Expected Dividend yield	—%	—%

Summary of Restricted Stock Unit Activity

A summary of RSU activity during the year ended December 31, 2021 is as follows:

	Number of Units Outstanding			Weighted Average Grant Date Fair Value
Outstanding at December 31, 2020		—		$	—
Granted		1,043,720		$	4.97
Vested		—		$	—
Forfeited		(636,000	)	$	4.49
Outstanding at December 31, 2021		407,720		$	5.72

Components of Stock-based Compensation Expense

The following table summarizes the components of stock-based compensation expense recorded in the Company’s statement of operations and comprehensive loss (in thousands):

	Year ended December 31,
	2021		2020
Research and development	$	2,388	$	1,480
Selling, general and administrative		6,819		2,203
Total stock-based compensation	$	9,207	$	3,683