You have an interesting project you want to work on and give access to a specific idea to a user who is not an Admin role user. Is this possible? YES
You can provide access to anyone in the system to get access to a project (or an idea) to add them to the Team. To do this, you need to be an Admin user.
Provide access to an idea to a normal user
Step 1: Open the Project
Step 2: Go on the right side to the block: Team
Step 3: Add Team Member with the team member button
Now, the user you selected has access to the project to collaborate.
The user will automatically get a notification to access this idea.