Note 3 - Summary of Significant Accounting Policies - Antidilutive Securities (Details) - shares |
12 Months Ended | |
|---|---|---|
Dec. 31, 2018 |
Dec. 31, 2017 |
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| Antidilutive securities (in shares) | 1,468,105 | 717,431 |
| Employee and Non-employee Stock Options [Member] | ||
| Antidilutive securities (in shares) | 639,359 | 480,035 |
| Common Stock Purchase Warrants [Member] | ||
| Antidilutive securities (in shares) | 807,563 | 216,213 |
| Deferred Share Units [Member] | ||
| Antidilutive securities (in shares) | 21,183 | 21,183 |
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- Definition Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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