Quarterly report pursuant to Section 13 or 15(d)

Equity (Details Textual)

v3.19.1
Equity (Details Textual) - USD ($)
1 Months Ended 3 Months Ended
Jan. 31, 2019
Mar. 31, 2019
Mar. 31, 2018
Equity (Textual)      
Sales of aggregate of common stock units 924,500    
Net proceeds on sale of common stock $ 400,000    
Net proceeds on exercise of warrants   $ 1,503,762
Common Stock [Member]      
Equity (Textual)      
Sales of aggregate of common stock units     30,237,894
Issuance of common stock, shares     30,237,894
Series A warrants [Member]      
Equity (Textual)      
Proceeds from warrants exercised   $ 1,500,000  
Description of warrant exercisable     Each series A warrant exercisable for one share of common stock at an exercise price of $0.60 per share.
Warrants exercised by warrant holders   2,500,000  
Aggregate series warrants     7,559,445
Warrant expired   4,900,000 5,000,000
Series B warrants [Member]      
Equity (Textual)      
Description of warrant exercisable     Each series B warrant exercisable for one share of Common Stock at an exercise price of $0.70 per share, resulting in gross proceeds of approximately $15.1 million (each unit was sold at $0.50 per unit), and net proceeds of approximately $13.8 million after deducting expenses relating to dealer-manager fees and other offering expenses.
Aggregate series warrants     22,678,393
Stock Options [Member]      
Equity (Textual)      
Stock option granted to employees   700,000  
Option exercise price minimum   $ 0.40  
Option exercise price maximum   $ 0.58  
Stock options, description   The options have an aggregated fair value of $0.2 million that was calculated using the Black-Scholes option-pricing model. Variables used in the Black-Scholes option-pricing model include: (1) discount rate range from 2.45% to 2.60% (2) expected life of 6 years, (3) expected volatility range from 78.5% to 79.0%, and (4) no expected dividends. During the three months ended March 31, 2019, options to purchase 0.1 million shares were cancelled upon the termination of employment for several employees.  
Total option expense   $ 300,000 $ 600,000
Unrecognized compensation expense   $ 2,500,000  
Stock options, term   10 years  
Stock options, vesting period   4 years  
Stock options outstanding   7,800,000  
Weighted average exercise price   $ 1.65  
Weighted average remaining contractual term   8 years 4 days