Share-based compensation (Tables)

6 Months Ended

Jun. 30, 2022

Share-based compensation

Schedule of Stock-based compensation expense

Share-based compensation expense recorded as research and development and general and administrative expenses in the condensed statements of operations is as follows (in thousands):

	Three Months Ended June 30,				Six Months Ended June 30,
	2022		2021		2022		2021
Research and development	$	462	$	368	$	907	$	522
General and administrative		865		381		1,730		552
	$	1,327	$	749	$	2,637	$	1,074

Weighted average assumptions used in option-pricing

The weighted average assumptions used in the Black-Scholes option-pricing model for stock options granted were:

	Six Months Ended June 30,
	2022			2021
Expected volatility		85.6	%		83.1	%
Risk-free interest rate		2.7	%		1.1	%
Expected term (in years)		5.97			6.04
Expected dividend yield		—			—
Fair value of common stock	$	3.64		$	25.60

Summary of option activity

A summary of option activity under the Plans and 2020 Plan during the six months ended June 30, 2022 is as follows:

				Weighted
		Weighted		average
		average		remaining
	Number of	exercise price		contractual
	shares	per share		term (years)
Outstanding at January 1, 2022	2,005,756	$	11.26	8.50
Granted	543,900		3.64	9.90
Forfeited	—		—	—
Exercised	(17,012)		1.87	7.86
Outstanding at June 30, 2022	2,532,644		9.69	8.41
Exercisable at June 30, 2022	980,061		7.84	7.59
Vested or expected to vest at June 30, 2022	2,532,644		9.69	8.41