Note 2 - Summary of Significant Accounting Policies - Antidilutive Securities (Details) - shares |
6 Months Ended | |||||||
---|---|---|---|---|---|---|---|---|
Jun. 30, 2021 |
Jun. 30, 2020 |
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Series A Convertible Preferred Stock [Member] | ||||||||
Antidilutive Securities Excluded from Computation of Earnings Per Share (in shares) | [1] | 0 | 0 | |||||
Series B Convertible Preferred Stock [Member] | ||||||||
Antidilutive Securities Excluded from Computation of Earnings Per Share (in shares) | [2] | 2,489,542 | 2,201,634 | |||||
Series C Convertible Preferred Stock [Member] | ||||||||
Antidilutive Securities Excluded from Computation of Earnings Per Share (in shares) | [3] | 0 | 0 | |||||
Common Stock Warrants [Member] | ||||||||
Antidilutive Securities Excluded from Computation of Earnings Per Share (in shares) | 9,793,599 | 2,358,329 | ||||||
Share-based Payment Arrangement, Option [Member] | ||||||||
Antidilutive Securities Excluded from Computation of Earnings Per Share (in shares) | 3,188,628 | 1,002,400 | ||||||
Restricted Stock Units (RSUs) [Member] | ||||||||
Antidilutive Securities Excluded from Computation of Earnings Per Share (in shares) | 684,000 | 0 | ||||||
Restricted Stock [Member] | ||||||||
Antidilutive Securities Excluded from Computation of Earnings Per Share (in shares) | 232 | 249 | ||||||
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