Net Loss Per Share - Summary of Antidilutive Securities Excluded From Computation Diluted Weighted Average Shares Outstanding (Detail) - shares	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Schedule Of Calculation Of Numerator And Denominator In Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share amount	7,972,333	6,459,862
Unvested Restricted Stock [Member]
Schedule Of Calculation Of Numerator And Denominator In Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share amount	505,703	1,062,568
Unvested Restricted Stock Units [Member]
Schedule Of Calculation Of Numerator And Denominator In Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share amount	1,954,651	498,300
Employee Stock Purchase Plan [Member]
Schedule Of Calculation Of Numerator And Denominator In Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share amount	10,959	17,639
Options to Purchase Common Stock [Member]
Schedule Of Calculation Of Numerator And Denominator In Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share amount	5,501,020	4,881,355