Annual report pursuant to Section 13 and 15(d)

Financial Instruments - Summary of Quantitative Information with Respect to Significant Unobservable Inputs (Detail)

v3.8.0.1
Financial Instruments - Summary of Quantitative Information with Respect to Significant Unobservable Inputs (Detail)
12 Months Ended
May 17, 2017
Mar. 31, 2017
Dec. 31, 2017
Dec. 31, 2016
Fair Value Inputs, Assets, Quantitative Information [Line Items]        
Volatility 70.00%      
Risk free rate 1.44%      
Discount for lack of marketability 0.00%      
Primary Warrant [Member]        
Fair Value Inputs, Assets, Quantitative Information [Line Items]        
Volatility       80.00%
Risk free rate       1.84%
Discount for lack of marketability       20.00%
Acacia Note Warrants [Member] | First Tranche [Member]        
Fair Value Inputs, Assets, Quantitative Information [Line Items]        
Volatility   65.00%   80.00%
Risk free rate   1.58%   1.61%
Discount for lack of marketability   10.00%   20.00%
Acacia Note Warrants [Member] | Second Tranche [Member]        
Fair Value Inputs, Assets, Quantitative Information [Line Items]        
Volatility   65.00%   80.00%
Risk free rate   1.64%   1.68%
Discount for lack of marketability   10.00%   20.00%
Bridge Loan Warrants [Member] | Bridge Loan [Member]        
Fair Value Inputs, Assets, Quantitative Information [Line Items]        
Volatility     70.00%  
Risk free rate     2.40%  
Discount for lack of marketability     10.00%