Net Loss Per Share - Summary of Potentially Dilutive Common Shares Excluded from Computation of Diluted Net Loss Per Share (Detail) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive Securities	4,913,122	4,093,032	4,913,122	4,093,032
Common Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive Securities	3,679,254	3,007,162	3,679,254	3,007,162
Restricted Common Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive Securities	1,105,415	949,683	1,105,415	949,683
Restricted Common Stock Awards [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive Securities	128,453	136,187	128,453	136,187