Quarterly report pursuant to Section 13 or 15(d)

Note 9 - Summary of Stock Options - Summary of Options Outstanding and Exercisable (Details)

v3.10.0.1
Note 9 - Summary of Stock Options - Summary of Options Outstanding and Exercisable (Details)
9 Months Ended
Sep. 30, 2018
$ / shares
shares
Exercise price range, upper limit (in dollars per share) $ 2.64
Options outstanding, number (in shares) | shares 4,298,565
Options outstanding, weighted average exercise price (in dollars per share) $ 4.64
Options outstanding, weighted average remaining contractual term (Year) 8 years 182 days
Options exercisable, number exercisable (in shares) | shares 1,406,846
Options exercisable, weighted average exercise price (in dollars per share) $ 5.56
Range One [Member]  
Exercise price range, lower limit (in dollars per share) 1.75
Exercise price range, upper limit (in dollars per share) $ 1.97
Options outstanding, number (in shares) | shares 535,000
Options outstanding, weighted average exercise price (in dollars per share) $ 1.95
Options outstanding, weighted average remaining contractual term (Year) 9 years 219 days
Options exercisable, number exercisable (in shares) | shares 31,250
Options exercisable, weighted average exercise price (in dollars per share) $ 1.97
Range Two [Member]  
Exercise price range, lower limit (in dollars per share) 2.02
Exercise price range, upper limit (in dollars per share) $ 2.83
Options outstanding, number (in shares) | shares 167,500
Options outstanding, weighted average exercise price (in dollars per share) $ 2.45
Options outstanding, weighted average remaining contractual term (Year) 9 years 219 days
Options exercisable, number exercisable (in shares) | shares 10,678
Options exercisable, weighted average exercise price (in dollars per share) $ 2.64
Range Three [Member]  
Exercise price range, lower limit (in dollars per share) 3.11
Exercise price range, upper limit (in dollars per share) $ 3.82
Options outstanding, number (in shares) | shares 481,876
Options outstanding, weighted average exercise price (in dollars per share) $ 3.56
Options outstanding, weighted average remaining contractual term (Year) 9 years 109 days
Options exercisable, number exercisable (in shares) | shares 59,910
Options exercisable, weighted average exercise price (in dollars per share) $ 3.76
Range Four [Member]  
Exercise price range, lower limit (in dollars per share) 4.30
Exercise price range, upper limit (in dollars per share) $ 4.97
Options outstanding, number (in shares) | shares 1,435,464
Options outstanding, weighted average exercise price (in dollars per share) $ 4.53
Options outstanding, weighted average remaining contractual term (Year) 8 years 255 days
Options exercisable, number exercisable (in shares) | shares 406,550
Options exercisable, weighted average exercise price (in dollars per share) $ 4.63
Range Five [Member]  
Exercise price range, lower limit (in dollars per share) 5.01
Exercise price range, upper limit (in dollars per share) $ 5.67
Options outstanding, number (in shares) | shares 771,655
Options outstanding, weighted average exercise price (in dollars per share) $ 5.35
Options outstanding, weighted average remaining contractual term (Year) 8 years 36 days
Options exercisable, number exercisable (in shares) | shares 326,006
Options exercisable, weighted average exercise price (in dollars per share) $ 5.35
Range Six [Member]  
Exercise price range, lower limit (in dollars per share) 6
Exercise price range, upper limit (in dollars per share) $ 6.61
Options outstanding, number (in shares) | shares 551,058
Options outstanding, weighted average exercise price (in dollars per share) $ 6.04
Options outstanding, weighted average remaining contractual term (Year) 7 years
Options exercisable, number exercisable (in shares) | shares 371,812
Options exercisable, weighted average exercise price (in dollars per share) $ 6.02
Range Seven [Member]  
Exercise price range, lower limit (in dollars per share) 7
Exercise price range, upper limit (in dollars per share) $ 7.92
Options outstanding, number (in shares) | shares 317,634
Options outstanding, weighted average exercise price (in dollars per share) $ 7.66
Options outstanding, weighted average remaining contractual term (Year) 7 years 182 days
Options exercisable, number exercisable (in shares) | shares 162,262
Options exercisable, weighted average exercise price (in dollars per share) $ 7.67
Range Eight [Member]  
Options outstanding, number (in shares) | shares 38,135
Options outstanding, weighted average exercise price (in dollars per share) $ 9.92
Options outstanding, weighted average remaining contractual term (Year) 4 years 36 days
Options exercisable, number exercisable (in shares) | shares 38,135
Options exercisable, weighted average exercise price (in dollars per share) $ 9.92
Range Nine [Member]  
Exercise price range, lower limit (in dollars per share) 59.60
Exercise price range, upper limit (in dollars per share) $ 149.04
Options outstanding, number (in shares) | shares 243
Options outstanding, weighted average exercise price (in dollars per share) $ 100.46
Options outstanding, weighted average remaining contractual term (Year) 2 years 73 days
Options exercisable, number exercisable (in shares) | shares 243
Options exercisable, weighted average exercise price (in dollars per share) $ 100.46