Equity Incentive Plan - Schedule of Stock Option Activity Under 2019 Plan (Detail) - 2019 Plan [Member] - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options outstanding, beginning balance		4,260,753	514,710
Options granted		1,415,371	4,137,750
Options exercised		(4,676)
Options forfeited		(496,842)	(387,186)
Options expired		(80,924)	(4,521)
Options outstanding, ending balance		5,093,682	4,260,753	514,710
Options vested and exercisable		2,462,298
Options vested and expected to vest		5,093,682
Weighted average exercise price, beginning balance		$ 8.46	$ 9.90
Weighted average exercise price, granted		7.88	8.49
Weighted average exercise price, exercised		8.00
Weighted average exercise price, forfeited		8.09	8.85
Weighted average exercise price, expired		8.16	8.85
Weighted average exercise price, ending balance		8.34	$ 8.46	$ 9.90
Weighted average exercise price, vested and exercisable		8.36
Weighted average exercise price, vested and expected to vest		$ 8.34
Weighted average remaining contractual term, balance		8 years 4 months 24 days	9 years	10 years
Options vested and exercisable, December 31, 2021		8 years 1 month 6 days
Options vested and expected to vest, December 31, 2021		8 years 4 months 24 days
Aggregate intrinsic value, exercised	[1]	$ 1
Aggregate intrinsic value, ending balance	[1]	24
Options vested and expected to vest, December 31, 2021	[1]	$ 24

[1] Aggregate intrinsic value (in thousands) represents the difference between the estimated fair value of the underlying common stock and the exercise price of outstanding, in-the-money options.