Note 3 - Investment Securities - Schedule of Investment Securities (Details) (Parentheticals) - US Government Agencies Debt Securities [Member]	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Short-Term Investments [Member] | Minimum [Member]
Maturity date	Jan. 01, 2024	Jan. 01, 2023
Short-Term Investments [Member] | Maximum [Member]
Maturity date	Jun. 30, 2024	Dec. 31, 2023
Long Term Investments [Member] | Minimum [Member]
Maturity date		Jan. 01, 2024
Long Term Investments [Member] | Maximum [Member]
Maturity date		Feb. 29, 2024