But, Motorola has now updated the Touchless Control app to help you find your device if you've lost it... assuming the device is in a place where it can hear you. Assuming your device can hear you and it isn't wedged too deeply in the couch cushions or somewhere in another room or maybe in the car, all you'll have to do is say "Okay Google Now, find my phone"; and, the device will trigger an alarm to help you find your phone.
In the case that your device can't hear you, you can still use Google's new Android Device Manager to trigger an alarm that will sound at full volume for 5 minutes. It's always good to have backup.
Download: Touchless Control