Stock-based compensation (Tables)

3 Months Ended

Mar. 31, 2020

Stock-based compensation

Schedule of summary of stock option activity

The following table summarizes the Company’s stock option activity since January 1, 2020 (in thousands, except share and per share amounts):

				Weighted
		Weighted		Average
		Average		Remaining	Aggregate
	Number of	Exercise		Contractual	Intrinsic
	Shares	Price		Term	Value
				(in years)
Outstanding as of December 31, 2019	2,999,284	$	7.63	8.1	$	15,840
Granted	—		—
Exercised	(78,598)		0.10
Forfeited	(16,709)		7.41
Outstanding as of March 31, 2020	2,903,977	$	7.84	7.9	$	8,405
Options exercisable as of March 31, 2020	842,678	$	1.04	6.0	$	6,226
Options unvested as of March 31, 2020	2,061,299	$	10.62	8.7	$	2,179

Schedule of stock-based compensation expense

Stock-based compensation expense was classified in the condensed consolidated statements of operations and comprehensive loss as follows (in thousands):

	Three months ended March 31,
	2020		2019
Research and development expenses	$	677	$	261
General and administrative expenses		1,417		122
	$	2,094	$	383