Just as the title states, I am looking for a web-based tool that would allow users to submit an idea to be voted upon. Additionally, all other users should be able to see all current ideas and I should be able to vote on certain ones. It would also be nice if I could see once a particular idea had a certain number of votes.
I am one of the developers of PollUnit. With https://pollunit.com you can create votings where users can add ideas.
Here is an example how a dot voting could look like:
We released a idea collection/feedback/brainstorming feature. I think this is exactly what you are looking for. See screenshot: