Net Loss Per Share - Computation of Diluted Weighted-Average Shares Outstanding (Detail) - shares		3 Months Ended
		Mar. 31, 2021	Mar. 31, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total of common stock equivalents		4,428,690	6,653,462
Options to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total of common stock equivalents		3,856,204	5,432,554
Restricted Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total of common stock equivalents		454,635	936,591
Nonvested Founder Shares [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total of common stock equivalents	[1]	117,851	284,317

[1] Represents 117,851 shares of common stock that are issued and outstanding but that were subject to vesting based on service requirements at March 31, 2021 and are not included in stockholders’ equity pursuant to GAAP.