Bug

components.my-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  inElementContainer: Ember.computed(function() {
    return document.querySelector('.ember-application');
  }),
  
  didInsertElement() {
    this._super(...arguments);
    
    Ember.run.next(() => {
    	this.element.parentNode.setAttribute('aria-describedby', this.get('id'));
    });
  },

  willDestroyElement() {
    this._super(...arguments);
    
    this.element.parentNode.removeAttribute('aria-describedby');
  },
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  show: true,
  
  actions: {
    toggleShow() {
      this.toggleProperty('show');
    }
  }
});

templates.application.hbs

<button {{action 'toggleShow'}}>{{if show 'hide' 'show'}}</button>

<br><br>
<span>&nbsp;</span>

<div id="parent">
  {{#if show}}
    {{my-component id='some-id'}}
  {{/if}}
</div>

templates.components.my-component.hbs

{{#-in-element inElementContainer}}
	Hello!
{{/-in-element}}

twiddle.json

{
  "version": "0.12.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "beta",
    "ember-template-compiler": "beta",
    "ember-testing": "beta"
  },
  "addons": {
  }
}