Stockholders' Equity - Summary of Stock Option Activity (Details) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares
Number of Outstanding Options
Balance at December 31, 2020 | shares	3,136,076
Granted | shares	1,000,405
Exercised | shares	(489,179)
Cancelled | shares	(229,078)
Balance at September 30, 2021 | shares	3,418,224	3,136,076
Vested and expected to vest at September 30, 2021 | shares	3,418,224
Exercisable at September 30, 2021 | shares	1,204,210
Weighted Average Exercise Price
Balance at December 31, 2020 | $ / shares	$ 5.23
Granted | $ / shares	8.81
Exercised | $ / shares	2.24
Cancelled | $ / shares	6.56
Balance at September 30, 2021 | $ / shares	6.62	$ 5.23
Vested and expected to vest at September 30, 2021 | $ / shares	6.62
Exercisable at September 30, 2021 | $ / shares	$ 4.66
Weighted Average Remaining Contractual Term (In Years)
Balance	8 years 4 months 28 days	7 years 11 months 12 days
Vested and expected to vest at September 30, 2021	8 years 4 months 28 days
Exercisable at September 30, 2021	7 years 6 months 3 days
Aggregate Intrinsic Value
Balance | $	$ 601	$ 8,963
Vested and expected to vest at September 30, 2021 | $	601
Exercisable at September 30, 2021 | $	$ 510