Stock-Based Compensation - Summary of Stock Option Activity under Company's Plans (Detail) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($) $ / shares shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options outstanding, beginning balance | shares	107,500
Options outstanding, ending balance | shares	107,500
Options Outstanding, Options exercisable | shares	87,500
Options Outstanding, Options vested or expected to vest | shares	107,164
Weighted-Average Exercise Price Per Share, Options outstanding, beginning balance | $ / shares	$ 17.34
Weighted- Average Exercise Price Per Share, Options outstanding, ending balance | $ / shares	17.34
Weighted- Average Exercise Price Per Share, Options exercisable | $ / shares	14.53
Weighted-Average Exercise Price Per Share, Options vested or expected to vest | $ / shares	$ 17.30
Weighted-Average Remaining Contractual Term in Years, Options outstanding	6 years 4 months 17 days
Weighted-Average Remaining Contractual Term in Years, Options exercisable	5 years 8 months 23 days
Weighted-Average Remaining Contractual Term in Years, Options vested or expected to vest	6 years 4 months 13 days
Aggregate Intrinsic Value, Options outstanding | $	$ 5,602
Aggregate Intrinsic Value, Options exercisable | $	4,806
Aggregate Intrinsic Value, Options vested or expected to vest | $	$ 5,589