XML 80 R64.htm IDEA: XBRL DOCUMENT v3.8.0.1
Long-term debts, Net - Schedule of Assumptions Used to Estimate Fair Value of Warrants (Detail)
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]      
Expected term (in years)   10 years 10 years
Risk-free interest rate   1.56% 2.24%
Expected volatility 82.50% 90.47% 114.33%
Expected dividend yield 0.00% 0.00% 0.00%
Minimum [Member]      
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]      
Expected term (in years) 29 days    
Risk-free interest rate 1.02%    
Maximum [Member]      
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]      
Expected term (in years) 9 years    
Risk-free interest rate 2.35%