I've got a custom board with Atmega328P-AU and I'm using the ArduinoISP to program it. No issues there. I run into the issue where I can't do a serial monitor. I thought for sure I've been able to do it previously. I'm on OS X 10.11.2 using IDE 1.6.7. I did a fresh install of the OS back in November and hadn't done any programming since then so the IDE is also a fresh install. I don't see the ISP available in my Tools->Ports. I only see bluetooth.
Any ideas? I shouldn't need any drivers because I'm OS X according the Arduino's documentation.