Chris Snider of the Just Talking Podcast interviewed a Dexcom software engineer last week and you might want to listen to the interview: http://justtalkingpodcast.com/2015/04/21/about-dexcom-with-cto-jorge-valdes/
I listen to Just Talking through iTunes, but the link above lets you listen on your computer or other device.
In the interview they talk about Apple Watch versus Pebble, Apple vs. Android, etc. and etc. Eventually it will come to all devices and they are hiring teams for Android, watch devices, etc.
Longterm I am waiting for the Dexcom G5 which will remove the need for a receiver and go directly to a phone.