Stock-Based Compensation - Summary of Stock Option Activity under Company's Plans (Detail) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options outstanding, beginning balance	140,000
Options Outstanding, Granted	25,000
Options Outstanding, Exercised	(37,500)
Options Outstanding, Forfeited	(5,000)
Options outstanding, ending balance	122,500
Options Outstanding, Options exercisable	102,500
Options Outstanding, Options vested or expected to vest	121,302
Weighted-Average Exercise Price Per Share, Options outstanding, beginning balance	$ 13.14
Weighted-Average Exercise Price Per Share, Granted	29.64
Weighted-Average Exercise Price Per Share, Exercised	12.28
Weighted-Average Exercise Price Per Share, Forfeited	29.64
Weighted- Average Exercise Price Per Share, Options outstanding, ending balance	16.10
Weighted- Average Exercise Price Per Share, Options exercisable	13.45
Weighted-Average Exercise Price Per Share, Options vested or expected to vest	$ 15.96
Weighted-Average Remaining Contractual Term in Years, Options outstanding	6 years 21 days
Weighted-Average Remaining Contractual Term in Years, Options exercisable	5 years 4 months 6 days
Weighted-Average Remaining Contractual Term in Years, Options vested or expected to vest	6 years 7 days
Aggregate Intrinsic Value, Exercised	$ 1,036	$ 416
Aggregate Intrinsic Value, Options outstanding	3,413
Aggregate Intrinsic Value, Options exercisable	3,127
Aggregate Intrinsic Value, Options vested or expected to vest	$ 3,396