Some moderators want to oversee all ideas, especially those that are in the 'pending approval' stage before making them live in the community. Ideas that require moderation approval (if set by administrator from community settings) or ideas that were flagged inappropriate are queued up in 'pending' approval stage. These ideas can easily be approved from the moderation panel by editing (if required) and moving them to next stage.
To review these ideas in the moderation panel, navigate into your community settings and go into the Moderation --> Ideas section (screenshot below).
Each idea will have an Action menu (black button you can see below) - when clicked on, will display the option to change the status of an idea
Furthermore, it is possible to bulk approve or delete ideas, move ideas from one campaign to another (without campaign specific custom fields), one stage to another or merge two similar/duplicate ideas from this same moderation panel.
Help article on merge ideas: https://support.ideascale.com/moderation/moderation-merge-ideas