Note 11 - Subsequent Event	3 Months Ended
Mar. 31, 2023
Notes to Financial Statements
Subsequent Events [Text Block]	NOTE 11 – SUBSEQUENT EVENT On April 12, 2023, the Company learned of a cyber-attack that resulted in a disruption to the computer systems of Middlefield Bank, the Company’s banking subsidiary. Middlefield Bank took immediate action to remediate the security vulnerability and retained a cybersecurity firm to investigate the nature and scope of the incident, evaluate systems and identify solutions, and confirm what data has been impacted by this event, if any. Middlefield Bank also notified law enforcement. Middlefield Bank’s products and services are fully operational. Middlefield Bank has placed additional security measures in place and will continue to actively monitor any suspicious activity. The investigation is on-going at this time, including confirming what, if any, customer data has been impacted by this event. We have incurred expenses to investigate and remediate the cyber-attack and expect to continue to incur expenses. Middlefield Bank has retained special legal counsel. Although cyber-attacks can be unpredictable, the Company does not currently expect this incident will have a material impact on its business operations or its financial results.

Note 11 - Subsequent Event

3 Months Ended

Mar. 31, 2023

NOTE 11 – SUBSEQUENT EVENT

On April 12, 2023, the Company learned of a cyber-attack that resulted in a disruption to the computer systems of Middlefield Bank, the Company’s banking subsidiary. Middlefield Bank took immediate action to remediate the security vulnerability and retained a cybersecurity firm to investigate the nature and scope of the incident, evaluate systems and identify solutions, and confirm what data has been impacted by this event, if any. Middlefield Bank also notified law enforcement. Middlefield Bank’s products and services are fully operational. Middlefield Bank has placed additional security measures in place and will continue to actively monitor any suspicious activity. The investigation is on-going at this time, including confirming what, if any, customer data has been impacted by this event.

We have incurred expenses to investigate and remediate the cyber-attack and expect to continue to incur expenses. Middlefield Bank has retained special legal counsel. Although cyber-attacks can be unpredictable, the Company does not currently expect this incident will have a material impact on its business operations or its financial results.