The phrase "I don't have much of an idea" is correct and usable in written English. It can be used to express that you lack understanding or knowledge of a certain situation, topic, or concept. For example, you could say "I don't have much of an idea about what kind of car I should buy.".
If the simple act of approaching a large corporation enables it to steal the idea, I'd say you don't have much of an idea.
He didn't have much of an idea about how a mutual fund functioned.
Good ideas don't have much of a chance of survival with their constant negative feedback.
– A doctor "I don't have much idea about the CPMP.
Many doctors also mentioned that they were unaware about the code: "I don't have much idea about the CPMP.
"I don't have much.
They don't have much of it.
Ludwig does not simply clarify my doubts with English writing, it enlightens my writing with new possibilities
Simone Ivan Conte
Software Engineer at Adobe, UK