Unbound variable ionic

I'm getting an unbound variable when I load my sass for ionic. I am trying to override the checkbox and the ionicon variable will not resolve

// The path for our ionicons font files, relative to the built CSS in www/css
$ionicons-font-path: "../lib/ionic/fonts" !default;

// Include all of Ionic
@import "www/lib/ionic/scss/ionic";

.following {
  .checkbox input:before, .checkbox-icon:before {
    content: $ionicon-var-android-add-circle;
  }
}