Net Loss Per Share - Summary of Anti-Dilutive Common Stock Equivalents Outstanding (Detail) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents	5,352,918	3,463,965	5,352,918	3,463,965
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents	5,313,821	3,445,537	5,313,821	3,445,537
Restricted Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents	30,400		30,400
Employee Stock Purchase Plan [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents	8,697	7,192	8,697	7,192
Restricted Stock Awards [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents		11,236		11,236