Note 10 - Shareholders' Equity (Details Textual) - USD ($) |
3 Months Ended | 12 Months Ended |
|---|---|---|
Mar. 31, 2021 |
Dec. 31, 2021 |
|
| Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in shares) | 40,000 | |
| Stock Issued During Period, Value, Stock Options Exercised | $ 244,000 | $ 244,000 |
| Stock Issued During Period, Shares, Exercise of Common Stock Warrants (in shares) | 0 |
| X | ||||||||||
- Definition The number of shares issued during the period due to the exercise of common stock warrants. No definition available.
|
| X | ||||||||||
- Definition Number of share options (or share units) exercised during the current period. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| 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
|