Ember app errors with es5

[jgadbois]

I recently built a simple Glimmer app. It's all working fine with the defautl tsconfig, however if I change the target to es5, I get the following error when running the app.

resolver-configuration.js:1 Uncaught TypeError: Class constructor Application cannot be invoked without 'new'
    at new App (resolver-configuration.js:1)
    at index.ts:5
    at objKeys (app.js:4)
    at app.js:5

Here are the versions specified in the package.json

    "@glimmer/application": "^0.8.0",
    "@glimmer/application-pipeline": "^0.9.0",
    "@glimmer/blueprint": "~0.6.4",
    "@glimmer/component": "^0.8.0",
    "@glimmer/inline-precompile": "^1.0.0",
    "@glimmer/resolver": "^0.4.1",
    "@glimmer/test-helpers": "^0.30.0",
    "@types/qunit": "^2.0.31",
    "broccoli-asset-rev": "^2.5.0",
    "ember-cli": "^2.14.0",
    "ember-cli-dependency-checker": "^2.0.1",
    "ember-cli-inject-live-reload": "^1.6.1",
    "ember-cli-sass": "^6.2.0",
    "ember-cli-tslint": "^0.1.3",
    "ember-cli-uglify": "^2.0.0-beta.1",
    "qunitjs": "^2.3.3",
    "regenerator-runtime": "^0.11.0",
    "typescript": "^2.2.2"