Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity (Details Textual)

v3.20.1
Stockholders' Equity (Details Textual) - USD ($)
1 Months Ended 3 Months Ended
May 09, 2020
May 25, 2020
May 19, 2020
Sep. 26, 2019
Dec. 31, 2014
Mar. 31, 2020
Mar. 31, 2019
Apr. 20, 2020
Dec. 31, 2019
Stockholders' Equity (Textual)                  
Aggregate fair value of warrants issued           $ 1,725,000    
Shares issued for cashless exercise of warrants           447,107      
Proceed for cashless exercise of warrants           $ 3,042,173      
Shares issued for cashless exercise of options           2,434      
Proceed for cashless exercise of options           $ 73,020      
Stock options exercisable period           10 years      
Number of shares available for future grants under plan           1,155,086      
Vesting period           4 years      
Unrecognized stock-based compensation expense           $ 116,000      
Aggregate intrinsic value of warrants vested and outstanding           0 $ 0    
Recognized additional compensation expense           $ 1,500,000      
Stockholders equity, reverse split       The Company's Board of Directors approved a 1-for-4 reverse split of the Common Stock, which was effective on the NASDAQ Capital Market on September 30, 2019. As a result of the reverse stock split, every 4 shares of issued and outstanding common stock were converted into 1 share of issued and outstanding common stock, with all fractional shares rounded up to the nearest whole share, and the Company's authorized share of common stock were reduced from 200,000,000 to 50,000,000 shares. All share and per share amounts have been retroactively restated to reflect this reverse stock split.          
Warrant [Member]                  
Stockholders' Equity (Textual)                  
Warrants to purchase of common stock           34,114      
Excercise of warrants           46,313      
Subsequent Event [Member]                  
Stockholders' Equity (Textual)                  
Excercise of warrants               257,441  
Stock Option and Equity Incentive Plan [Member]                  
Stockholders' Equity (Textual)                  
Number of options granted         5,152,942        
Employee Stock Option [Member]                  
Stockholders' Equity (Textual)                  
Number of options granted           600,000      
Unrecognized stock-based compensation expense           $ 66,250,000      
Unvested stock options weighted average remaining service period           3 years 8 months 19 days      
Weighted average fair value of options granted           $ 39.24      
Aggregate intrinsic value of warrants outstanding           $ 85,466,000     $ 115,731,000
Weighted average remaining service period           7 years 9 months 25 days      
Employee Stock Option [Member] | Subsequent Event [Member]                  
Stockholders' Equity (Textual)                  
Exercise price $ 45.61 $ 31.88 $ 28.00            
Options awarded 350,000 150,000 100,000            
Aggregate fair value of options $ 13,100,000 $ 4,000,000 $ 2,300,000            
Stock options term, description 10-year term vesting over 4-year period. 10-year term vesting over a 4-year period 10-year term vesting over a 4-year period            
Discount rate 0.51% 0.67% 0.83%            
Expected life term 6 years 2 months 30 days 6 years 2 months 30 days 6 years 2 months 30 days            
Expected volatility rate 107.00% 108.00% 108.00%            
Expected dividends rate 0.00% 0.00% 0.00%