Note 7 - Stock-based Compensation (Tables)
|9 Months Ended|
Sep. 30, 2023
|Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]||
Tabular disclosure of the significant assumptions used during the year to estimate the fair value of stock options, including, but not limited to: (a) expected term of share options and similar instruments, (b) expected volatility of the entity's shares, (c) expected dividends, (d) risk-free rate(s), and (e) discount for post-vesting restrictions.
Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef