Annual report pursuant to Section 13 and 15(d)

Derivative Liability and Fair Value Measurements (Estimate the fair value of warrants outstanding) (Detail)

v3.8.0.1
Derivative Liability and Fair Value Measurements (Estimate the fair value of warrants outstanding) (Detail) - USD ($)
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Value of warrants outstanding:      
Fair value of warrants $ 152,927 $ 173,131 $ 240,786
Monte Carlo Options Lattice Pricing Model Warrants Outstanding      
Assumptions for Pricing Model:      
Expected term in years 7 months 2 days 1 year 2 months 19 days 2 years 7 months 6 days
Volatility range for years 143.00% 100.00% 103.00%
Risk-free interest rate 1.76% 1.47% 1.06%
Expected annual dividends 0.00% 0.00% 0.00%