Note 7 - Warrants (Details Textual) - USD ($) |
3 Months Ended | 6 Months Ended | |
---|---|---|---|
Jun. 30, 2019 |
Jun. 30, 2019 |
Dec. 31, 2018 |
|
Class of Warrant or Right, Outstanding | 4,048,505 | 4,048,505 | 4,080,005 |
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ 4.34 | $ 4.34 | $ 4.35 |
Class of Warrant or Right, Exercised During Period | 24,000 | 29,000 | |
Class of Warrant or Right, Exercised During Period, Exercise Price | $ 4.75 | $ 4.75 | |
Proceeds from Warrant Exercises | $ 114,000 | $ 138,000 |