Stockholder's equity (deficit) (Tables)

12 Months Ended

Dec. 31, 2021

Stockholder's equity (deficit)

Schedule of common stock reserved for issuance

	Year Ended December 31,
	2021	2020
Options outstanding under the 2018 Stock Option and Grant Plan	2,011,891	2,148,019
Options outstanding under the 2019 Stock Option and Incentive Plan	3,209,203	1,585,293
Options available for future grant	1,889,299	2,127,544
Common stock available for ATM program	5,000,000	—
2019 Employee Stock Purchase Plan	872,429	543,963
	12,982,822	6,404,819

Summary of restricted stock activity

The following table summarizes restricted stock activity since December 31, 2019:

		Grant-Date Fair
	Number of Shares	Value
Unvested restricted common stock as of December 31, 2019	80,190	$	—
Early exercise of unvested stock options	491,207		0.65
Shares vesting	(416,248)		0.65
Unvested restricted common stock as of December 31, 2020	155,149		0.52
Shares vesting	(155,149)		0.52
Unvested restricted common stock as of December 31, 2021	—	$	-