Do angel investors invest in companies that have just an idea?
An idea is worth next to nothing without a team to implement. You can't legally own an idea. So you have to build the business on top of it to give it value.
Here's some recommended reading:
I Had That Idea Years Ago
Do You Have An Invention?
Your Idea Has No Value
The Real Truth About Selling Your Invention
Idea or Implementation
Ideas are Easy, Doing Stuff is Hard