How to override the primary key with a JSON API attribute

I've got a model called "Membership" that has a string attribute "inviteToken" which I would like to use as my primary key.

I've created the following serializer, but cannot get it to pick up the primary key from the JSON.

app/serializers/membership.js:

import DS from 'ember-data';

export default DS.JSONAPISerializer.extend({
  primaryKey: 'invite-token' // also tried 'inviteToken'
});

The specific error I'm getting is:

Error while processing route: invitations.show Assertion Failed: You must include an 'id' for membership in an object passed to 'push'
Error: Assertion Failed: You must include an 'id' for membership in an object passed to 'push'

API Response:

{
  "jsonapi":{
    "version":"1.0"
  },
  "data":{
    "type":"membership",
    "id":"30",
    "attributes":{
      "invite-token":"5bGo7IhZh93E4SB07VWauw"
    }
  }
}

The strange thing is that if I use "type" as the primary key, I see "membership" as the id in the ember inspector. It's as if ember data doesn't know how to use something from the "attributes". I'm using ember data 2.4.0.