Quarterly report pursuant to Section 13 or 15(d)

Note 8 - Summary of Stock Options - Summary of Options Outstanding and Exercisable (Details)

v3.7.0.1
Note 8 - Summary of Stock Options - Summary of Options Outstanding and Exercisable (Details)
6 Months Ended
Jun. 30, 2017
$ / shares
shares
Options outstanding, weighted average exercise price (in dollars per share) $ 6.15
Options outstanding, weighted average remaining contractual term (Year) 8 years 299 days
Options exercisable, number exercisable (in shares) | shares 603,985
Options exercisable, weighted average exercise price (in dollars per share) $ 6.83
Options outstanding, number (in shares) | shares 2,287,572
Range One [Member]  
Options outstanding, weighted average exercise price (in dollars per share) $ 2.64
Options outstanding, weighted average remaining contractual term (Year) 7 years 317 days
Options exercisable, number exercisable (in shares) | shares 6,771
Options exercisable, weighted average exercise price (in dollars per share) $ 2.64
Options outstanding, number (in shares) | shares 12,500
Range Two [Member]  
Options outstanding, weighted average exercise price (in dollars per share) $ 3.76
Options outstanding, weighted average remaining contractual term (Year) 7 years 222 days
Options exercisable, number exercisable (in shares) | shares 39,011
Options exercisable, weighted average exercise price (in dollars per share) $ 3.76
Exercise price range, lower limit (in dollars per share) 3.68
Exercise price range, upper limit (in dollars per share) $ 3.76
Options outstanding, number (in shares) | shares 66,876
Range Three [Member]  
Options outstanding, weighted average exercise price (in dollars per share) $ 4.62
Options outstanding, weighted average remaining contractual term (Year) 8 years 211 days
Options exercisable, number exercisable (in shares) | shares 141,577
Options exercisable, weighted average exercise price (in dollars per share) $ 4.78
Exercise price range, lower limit (in dollars per share) 4.46
Exercise price range, upper limit (in dollars per share) $ 4.92
Options outstanding, number (in shares) | shares 427,829
Range Four [Member]  
Options outstanding, weighted average exercise price (in dollars per share) $ 5.22
Options outstanding, weighted average remaining contractual term (Year) 9 years 175 days
Options exercisable, number exercisable (in shares) | shares 75,491
Options exercisable, weighted average exercise price (in dollars per share) $ 5.22
Options outstanding, number (in shares) | shares 586,409
Range Five [Member]  
Options outstanding, weighted average exercise price (in dollars per share) $ 6
Options outstanding, weighted average remaining contractual term (Year) 8 years 171 days
Options exercisable, number exercisable (in shares) | shares 209,161
Options exercisable, weighted average exercise price (in dollars per share) $ 6
Options outstanding, number (in shares) | shares 557,753
Range Six [Member]  
Options outstanding, weighted average exercise price (in dollars per share) $ 6.35
Options outstanding, weighted average remaining contractual term (Year) 8 years 124 days
Options exercisable, number exercisable (in shares) | shares 43,466
Options exercisable, weighted average exercise price (in dollars per share) $ 6.35
Exercise price range, lower limit (in dollars per share) 6.24
Exercise price range, upper limit (in dollars per share) $ 6.40
Options outstanding, number (in shares) | shares 117,965
Range Seven [Member]  
Options outstanding, weighted average exercise price (in dollars per share) $ 7.67
Options outstanding, weighted average remaining contractual term (Year) 9 years 131 days
Options exercisable, number exercisable (in shares) | shares 42,593
Options exercisable, weighted average exercise price (in dollars per share) $ 7.70
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 472,325
Range Eight [Member]  
Options outstanding, weighted average exercise price (in dollars per share) $ 9.92
Options outstanding, weighted average remaining contractual term (Year) 5 years 146 days
Options exercisable, number exercisable (in shares) | shares 38,135
Options exercisable, weighted average exercise price (in dollars per share) $ 9.92
Options outstanding, number (in shares) | shares 38,135
Range Nine [Member]  
Options outstanding, weighted average exercise price (in dollars per share) $ 83.66
Options outstanding, weighted average remaining contractual term (Year) 120 days
Options exercisable, number exercisable (in shares) | shares 7,780
Options exercisable, weighted average exercise price (in dollars per share) $ 83.66
Exercise price range, lower limit (in dollars per share) 56
Exercise price range, upper limit (in dollars per share) $ 296
Options outstanding, number (in shares) | shares 7,780