I would say a few hundred million in volume could bring the bid back no problem....and this could happen at the drop of a hat if we get some news from the company.
Actually, we would probably get a billion volume day if we get anything from the company officially since there are so many investors watching this stock closely....IMHO
Remember people to only play with the money your wife/husband/significant other won't disembowel you for should you lose everything if your stock goes the way of the dodo!