One point Della makes is that some short story ideas can be moved on to become novel ideas too. However, a novel is not a short story idea with extra words and description. It needs to have sub-plots, character development, and the action can take place over a far longer period of time.
Turning little ideas into bigger ideas is something that many writers consider. Non-fiction writers especially, are encouraged to consider writing a non-fiction book on a subject, if they've had a handful of articles on that subject published.
My first book, 100 Ways For A Dog To Train Its Human, has been moved on twice. I can trace its origin back to a short filler (about 75 words in total, I think) in a dog magazine. I moved this on to become an 800-word article for a different dog magazine, before moving it on again into a 5,000-word book.
If you dream of moving on to bigger projects, whether it's from short stories to novels, or articles to non-fiction books, why not look back through some of your smaller ideas? It's quite possible, that if they were successful in one format, with a bit of work and development, they could work in another, larger, format too.
For more information about Della's book, Moving On, click here.