Mine came with one of those too. Ended up removing it and buying one of these Bluetooth adapters instead. Plugs right into that port(AMI/MMI) without need for the original adapter.
Works great for streaming music. I was surprised the radio has Bluetooth phone connectivity but not streaming.
They also have another version that plugs into the iPod end of the factory cable, but better to have less connections IMHO. Other companies also sell micro usb and lightning wired cables if you don't want Bluetooth, although I have never tried them to see how well they work.