Hello,

Sorry to say the green part was shaved off and the shrub has no means of growing foliage from the brown inner twigs and stems. A yew can recover from a trim like that (it takes a few years but it can recover) but an arborvitae, like most evergreens, can't. It will continue to grow from the green foliage that was left on top. You'll have to decide if you want to keep it with the brown base or not. But it's not dead.

Good-luck!