Note 6 - Common Stock (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Common Stock, Shares Authorized (in shares)	50,000,000		50,000,000
Common Stock, Par or Stated Value Per Share (in dollars per share)	$ 0.001		$ 0.001
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period (in shares)	2,500
Share-Based Payment Arrangement, Shares Withheld for Tax Withholding Obligation (in shares)		50,867
Share-Based Payment Arrangement, Decrease for Tax Withholding Obligation		$ 181
The Two Thousand Eighteen Equity Incentive Plan Member
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period (in shares)	2,500	202,126