Stock-Based Compensation - Stock Option Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Number of shares
Balance at beginning of period	1,420,942	489,222	350,914
Granted	175,086	978,415	152,016
Exercised	(27,783)	(2,527)	(1,377)
Early exercised		(471)	(427)
Canceled/forfeited	(70,037)	(43,697)	(11,904)
Balance at end of period	1,498,208	1,420,942	489,222
Vested and expected to vest at end of period	1,439,422
Exercisable at end of period	647,987
Weighted average exercise price per share
Balance at beginning of period (in dollars per share)	$ 10.35	$ 5.84	$ 5.81
Granted ( in dollars per share)	15.03	12.51	5.93
Exercised (in dollars per share)	6.29	5.93	5.57
Early exercised (in dollars per share)		5.93	5.93
Canceled/forfeited (in dollars per share)	12.41	8.58	5.93
Balance at end of period (in dollars per share)	10.87	$ 10.35	$ 5.84
Vested and expected to vest at end of period (in dollars per share)	10.80
Exercisable at end of period (in dollars per share)	$ 8.40
Weighted average remaining contractual term (years)
Weighted average remaining contractual term, outstanding	7 years 11 months 12 days
Weighted average remaining contractual term, Vested and expected to vest	7 years 10 months 28 days
Weighted average remaining contractual term, Exercisable	6 years 9 months 18 days