Note 10 - Net Income (Loss) Per Common Share (Details Textual) - shares shares in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 2020 |
Mar. 31, 2019 |
|
| Share-based Payment Arrangement, Option [Member] | ||
| Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares) | 1.9 | 2.7 |
| Warrant [Member] | ||
| Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares) | 2.7 | 3.0 |