Share-based compensation (Tables)

9 Months Ended

Sep. 30, 2020

Share-based compensation

Schedule of share based compensation expense

The Company recorded share‑based compensation expense in the following expense categories of its condensed consolidated statements of operations and comprehensive loss (in thousands):

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2020		2019		2020		2019
Research and development expenses	$	668	$	417	$	1,863	$	816
General and administrative expenses		842		402		3,087		1,184
	$	1,510	$	819	$	4,950	$	2,000

Schedule of share option activity

				Weighted
		Weighted		Average	Aggregate
	Number of	Average		Contractual	Intrinsic
	Shares	Exercise Price		Term	Value
				(in years)	(in thousands)
Outstanding as of December 31, 2019	2,634,346	$	9.57	9.04	$	6,107
Granted	1,319,484		11.69	—		—
Exercised	(18,554)		5.33	—		—
Forfeited	(155,491)		10.69	—		—
Outstanding as of September 30, 2020	3,779,785	$	10.24	8.76	$	33,340
Vested and expected to vest as of September 30, 2020	3,779,785	$	10.24	8.76	$	33,340
Options exercisable as of September 30, 2020	1,377,257	$	8.39	8.08	$	15,580

Schedule of assumptions used to determine the fair value of share options granted

	Three				Nine
	Months				Months
	Ended				Ended
	September 30,				September 30,
	2020		2019		2020		2019
Risk-free interest rate	0.3	%	1.7	%	1.4	%	2.2	%
Expected volatility	74.1	%	77.0	%	74.1	%	78.3	%
Expected dividend yield	—		—		—		—
Expected term (in years)	6.1		6.0		6.0		5.9