Our Desktop Application is not currently 'notarized' with the Apple Store, so OS X will complain about an unrecognized developer when you try to open the TSM Desktop Application. This does not mean the Application is not safe, and you are welcome to verify this by running an independent scan on it with your software of choice.
You can follow the instructions in this Apple Support article to open the Application in the Security & Privacy section of you settings: https://support.apple.com/en-us/HT202491