Annual report pursuant to Section 13 and 15(d)

Net Loss per Common Share - Additional Information (Detail)

v3.8.0.1
Net Loss per Common Share - Additional Information (Detail) - shares
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]      
Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount 13,701,104 13,676,979 9,889,452
Restricted Stock [Member]      
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]      
Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount 9,840,614 8,749,052 6,816,321