Note 13 - Warrants - Summary of Warrant Activity (Details) - USD ($) |
12 Months Ended | |
---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
|
Warrants outstanding (in shares) | 1,487,958 | 421,015 |
Warrants outstanding (in dollars per share) | $ 9.39 | $ 5,888 |
Warrants issued in connection with equity transactions (in shares) | 9,231,628 | 1,147,595 |
Warrants issued in connection with equity transactions (in dollars per share) | $ 3.46 | $ 2.03 |
Warrants exercised (in shares) | (7,617,147) | (17,857) |
Warrants exercised (in dollars per share) | $ 2.89 | $ 0.14 |
Warrants expired (in shares) | (44,037) | (62,795) |
Warrants expired (in dollars per share) | $ 174.58 | $ 209.23 |
Warrants outstanding (in shares) | 3,058,402 | 1,487,958 |
Warrants outstanding (in dollars per share) | $ 5.29 | $ 9.39 |
Aggregate intrinsic value of outstanding warrants | $ 37,143 | |
Weighted average remaining contractual terms (Year) | 3 years 182 days |