Note 9 - Shareholders' Equity (Details Textual) - USD ($) |
3 Months Ended | ||
|---|---|---|---|
Feb. 13, 2020 |
Mar. 31, 2021 |
Mar. 31, 2020 |
|
| Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in shares) | 40,000 | 7,200 | |
| Stock Issued During Period, Value, Stock Options Exercised | $ 244,000 | $ 16,000 | |
| Stock Issued During Period, Shares, Exercise of Common Stock Warrants (in shares) | 0 | ||
| Stock Issued During Period, Shares, New Issues (in shares) | 2,125,000 | ||
| Shares Issued, Price Per Share (in dollars per share) | $ 4 | ||
| Proceeds from Issuance of Common Stock | $ 8,500,000 | $ 7,682,000 | |
| Proceeds from Issuance of Common Stock, Net | $ 7,700,000 | ||
| Warrants Issued in Private Placement [Member] | |||
| Stock Issued During Period, Shares, Exercise of Common Stock Warrants (in shares) | 0 | ||
| X | ||||||||||
- Definition The cash inflow from the issuance of common stock, net of offering costs. No definition available.
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| X | ||||||||||
- Definition The number of shares issued during the period due to the exercise of common stock warrants. No definition available.
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| X | ||||||||||
- Definition The cash inflow from the additional capital contribution to the entity. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Per share or per unit amount of equity securities issued. No definition available.
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| X | ||||||||||
- Definition Number of new stock issued during the period. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Number of share options (or share units) exercised during the current period. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Value of stock issued as a result of the exercise of stock options. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Details
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