Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity - Summarizes Fortress warrant activities (Detail)

v3.8.0.1
Stockholders' Equity - Summarizes Fortress warrant activities (Detail) - USD ($)
$ / shares in Units, $ in Thousands
 9 Months Ended 12 Months Ended
Sep. 30, 2017
Dec. 31, 2016
Subsidiary or Equity Method Investee [Line Items]    
Weighted average remaining contractual life, Forfeited (years) 0 years  
Warrant [Member]    
Subsidiary or Equity Method Investee [Line Items]    
Number of shares, Outstanding 2,263,453  
Number of shares, Granted 816,180  
Forfeited (230,444)  
Number of shares, Outstanding 2,849,189 2,263,453
Number of shares, Exercisable 869,189  
Weighted average exercise price, Outstanding $ 3.62  
Weighted average exercise price, Granted 1.33  
Weighted average exercise price, Forfeited 8.39  
Weighted average exercise price, Outstanding $ 2.57 $ 3.62
Total weighted average intrinsic value, Outstanding $ 3,358,161 $ 79,800
Weighted average exercise price, Exercisable $ 3.96  
Total weighted average intrinsic value, Outstanding $ 79,800  
Total weighted average intrinsic value, Granted 329,954  
Total weighted average intrinsic value, Forfeited 0  
Total weighted average intrinsic value, Exercisable $ 546,561  
Weighted average remaining contractual life, Granted (years) 4 years 10 months 13 days  
Weighted average remaining contractual life (years), Outstanding 4 years 8 months 8 days 4 years 8 months 26 days
Weighted average remaining contractual life, Exercisable (years) 4 years 3 months 18 days