Android Emulator Intellij “smeared” display issue

I'm attempting to build my first Android app using Kotlin and Intellij (Community Edition 2018.2).

I've created my first Virtual Device, a Nexus 5 using all recommended system images and virtual device defaults.

However, when I try to use the emulator (either through running a sample app, or through using Cold Boot), the display looks strange, as though the images are distorted, as in this screenshot. It runs through the boot of the virtual device happily enough, displaying the correctly sized Google logo, etc.

I'm on a Mac running El Capitan 10.11.1.

Anyone seen this issue before? Thanks in advance for helping on this beginner question.