Summary of Status of Company's Stock Option Plans and Changes (Detail) (Employee Stock Option, USD $)
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Employee Stock Option
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Balances at beginning of period, Number of Shares 2,305,000 0
Number of Shares Options Assumed in the Merger   200,000
Number of Shares Options Granted 1,573,000 2,105,000
Number of Shares Options Exercised 0 0
Number of Shares Options Cancelled 250,000 0
Number of Shares Options Expired 0  
Balances at End of period, Number of shares 3,628,000 2,305,000
Number of Shares Options Vested and Exercisable 1,029,996  
Weighted Average Exercise Price Outstanding Beginning of period $ 3.96 $ 0
Weighted Average Exercise Price Options Assumed in the Merger   $ 3.05
Weighted Average Exercise Price Options Granted $ 3.22 $ 4.05
Weighted Average Exercise Price Options Exercised $ 0 $ 0
Weighted Average Exercise Price Options Cancelled $ 3.98 $ 0
Weighted Average Exercise Price Options Expired $ 0  
Weighted Average Exercise Price Outstanding end of period $ 3.64 $ 3.96
Weighted Average Exercise Price Options Vested and Exercisable $ 3.81