Cannot Get PS3 Controller Input Working on Mac

I'm trying implement gamepad controls into my game that I'm making in the Mac version of Unity, using a Playstation 3 controller. I am unable to get any response from the controller at all, regardless of what type of axes or joystick buttons I register in my Input Manager. I have checked using other applications to make sure the PS3 controller is connected to my Mac and working properly.

Can anyone point me to things I should try that might resolve this? Is there any official documentation from Unity about how to do this? I have not been able to find any so far, which seems like a huge oversight. Any help would be appreciated.