Sorry if this is common knowledge, but what exactly happens when Necrons 'fade out'? Specifically i'm interested in the one's that got trampled by a Dreadnough, smashed by a power fist, chopped up by an Avatar of Khaine or whatever and failed their WBB roll, Are they still repaired when they vanish?

I was under the impression that it's actually impossible to completely destroy a Necron, which seems kind of... Stupid. To say the least.