XML 26 R15.htm IDEA: XBRL DOCUMENT v3.19.2
Note 3 - Basis of Presentation and Summary of Significant Accounting Policies (Tables)
6 Months Ended
Jun. 30, 2019
Notes Tables  
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]
   
Six Months Ended June 30,
 
   
2019
   
2018
 
Common stock warrants
   
3,469,925
     
2,087,501
 
Stock options
   
309,276
     
214,353
 
     
3,779,201
     
2,301,854