XML 26 R25.htm IDEA: XBRL DOCUMENT v3.19.3
Note 5 - Equity - Stock Option Activity (Details) - $ / shares
9 Months Ended 12 Months Ended
Sep. 30, 2019
Dec. 31, 2018
Outstanding, number of shares (in shares) 4,535,681 2,628,749
Outstanding, weighted average exercise price (in dollars per share) $ 3.31 $ 1.31
Options granted, number of shares (in shares) 1,461,715 2,034,525
Options granted, weighted average exercise price (in dollars per share) $ 1.60 $ 6.21
Options exercised, number of shares (in shares)
Options exercised, weighted average exercise price (in dollars per share)
Options expired, number of shares (in shares) (91,813) (127,593)
Options expired, weighted average exercise price (in dollars per share)
Outstanding, number of shares (in shares) 5,905,583 4,535,681
Outstanding, weighted average exercise price (in dollars per share) $ 2.94 $ 3.31