Net Loss Per Common Share - Potential Common Stock Equivalents Excluded from Calculation of Diluted Net Loss Per Common Share (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]
Total	2,536,891	2,930,882	2,536,891	2,930,882
Outstanding Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	1,012,833	1,384,000	1,012,833	1,384,000
Unvested Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	1,524,058	1,546,882	1,524,058	1,546,882