Note 3 - Fair Value Measurements - Activity for Items Measured at Fair Value on a Recurring Basis (Details) - USD ($) |
9 Months Ended | |
---|---|---|
Sep. 30, 2017 |
Sep. 30, 2016 |
|
Balance | ||
Issuance of warrants | 4,582,170 | |
Change in fair value - loss | (219,014) | |
Balance | $ 4,363,156 | |
Stock Purchase Warrants [Member] | ||
Balance | $ 3,921,917 | |
Issuance of warrants | 2,483,848 | |
Exercise of warrants | (4,023,057) | |
Change in fair value - loss | 403,155 | |
Balance | $ 2,785,863 |