Carol, yes, you can sell your idea to another company to manufacture and develop and sell and you get the royalties. This is licensing. It's a great way to take a product that you know there is a market for, but that you yourself cannot develop and sell (monetary limitiations for example) and still get compensated for it.

Normally if the item is patentable, it is best that you obtain the patent yourself (very time consuming and costly). But you stand a much greater chance of licesning your product if it is already patented.

When you are ready to approach a manufacturer be sure you have a non disclosure form that they sign.

Do realize, that the royalties are quite small (average 5%). But if the product sells well, that can still be quite profitable.

Good luck!