Stock-based awards (Tables)

12 Months Ended

Dec. 31, 2019

Stock-based awards

Schedule of assumptions used to determine grant-date fair value of stock options granted

	Year Ended December 31,
	2019			2018
Weighted average risk‑free interest rate		2.12	%		2.99	%
Expected term (in years)		6.0			6.0
Expected volatility		73.75	%		70.88	%
Expected dividend yield		0	%		0	%

Summary of stock option activity

		Weighted-		Weighted-
		Average		Average	Aggregate
		Exercise		remaining	Intrinsic
	Number	Price per		contractual	Value
	of Options	Share		term (years)	(000's)
Balance Outstanding, December 31, 2017	—	$	—	—	$	—
Options granted	1,883,067		0.61	9.74
Options exercised	(12,586)		0.61
Options cancelled	(30,568)		0.61
Balance Outstanding, December 31, 2018	1,839,913		0.61	9.74		10,577
Options granted	1,912,352		12.42
Options exercised	(655,710)		0.69
Balance Outstanding, December 31, 2019	3,096,555	$	7.89	9.19	$	44,323
Exercisable, December 31, 2019	175,300	$	3.54	8.88	$	3,270
Vested and expected to vest, December 31, 2019	3,096,555	$	7.89	9.19	$	44,323