Equity Incentive Plan - Schedule of Stock Option Activity Under 2019 Plan (Detail) - 2019 Plan [Member] - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended	12 Months Ended
		Mar. 31, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options outstanding, beginning balance		4,260,753
Options granted		1,187,500
Exercised		(4,465)
Options forfeited		(146,366)
Options expired		(1,477)
Options outstanding, ending balance		5,295,945	4,260,753
Options Vested and Exercisable, March 31, 2021		1,224,595
Options Vested and Expected to vest, March 31, 2021		5,295,945
Weighted average exercise price, beginning balance		$ 8.46
Weighted average exercise price, granted		8.05
Exercised		8.00
Weighted average exercise price, forfeited		8.19
Weighted average exercise price, expired		8.00
Weighted average exercise price, ending balance		8.37	$ 8.46
Options Vested and Exercisable, March 31, 2021		8.22
Options Vested and Expected to vest, March 31, 2021		$ 8.37
Weighted average remaining contractual term, balance		9 years 1 month 6 days	9 years
Options Vested and Exercisable, March 31, 2021		8 years 9 months 18 days
Options Vested and Expected to vest, March 31, 2021		9 years 1 month 6 days
Aggregate intrinsic value, beginning balance	[1]	$ 806	$ 54
Options Vested and Exercisable, March 31, 2021	[1]	216
Options Vested and Expected to vest, March 31, 2021	[1]	$ 806

[1] Aggregate intrinsic value represents the difference between the estimated fair value of the underlying Common Stock (as defined below) and the exercise price of outstanding in-the-money options.