Not sure if you are being reasonable or not, you need to decide that, there aren't enough details for me to be sure. Can they fire you and still go through with the sale? Are they a decent, reasonable human being? If they are a reasonably decent human I would say, hey I put a lot of work into this thing and I think I deserve a piece of the action from the sale. Then see what they say and get their point of view. And if they offers you a deal make sure it is on paper. If they are a terrible human and they can fire you and still go through with the sale, then without a prior deal you are not getting anymore money than you previously negotiated. If they are a terrible human being and they need you for the sale then you negotiate a deal asap with the aid of a lawyer, or you walk.