OSX Setup Modify your adb_usb.ini
Open the ~/.android/adb_usb.ini file for editing and add
0x1949 0x0006
Save the file.
Note: Make sure there is only one entry per line. If the file does not exist, create the file and make sure you have the required Android SDK prerequisites configured. Restart the ADB server and confirm your Kindle Fire is detected
Open a terminal shell and execute:
[bash]adb kill-server
adb start-server
adb devices[/bash]
Locate Kindle Fire under the device list.
If your Kindle Fire is not being detected, you may need to reboot your computer or log out and log in for the changes to take effect.
Source: StackOverFlow