Except non is not an english word, it is a prefix of latin origin I'd use the two hyphens. Which is why american style manuals will always ask you to merge it with the subsequent word, without a hyphen
You used the dash in the wrong place Leaving non stranded doesn't work either as it is a bound morpheme, a prefix not a word (in english) I might be tempted to create an open compound, but non doesn’t stand alone.
