First of all, let me clarify my position... "I am THAT guy."
Today, I run my own company, and, I suspect, your "genius" has similar designs someday. That said, he's on your team now and is disrupting the normal workings of the company, despite all the good he can do by the speed of his intellect or a talent he possesses. These kinds of people don't live in the same boxes as the rest of your employees, nor do they see their contributions in the same ways. They love to focus on the brilliance of their ideas, forgetting that the execution of it is most important to legitimate success. And, they would see a failing of their idea as the product of someone else's inaction, and not their own.
Discipline (shame, fear, intimidation) seldom works for these guys. Why? Because they'll see a superiority position OVER the disciplinarian. They may be recoiling on the outside, but on the inside, they're thinking, "If you were so smart, why didn't you come up with the idea yourself?"
The way you need to handle this person is with education — but that's putting it mildly. The kind of education this person needs, and the kind you have to give needs to be just as ingenious as this person's wit. Telling them that their paperwork is crucial to the effort will fall on deaf ears and idle hands. They'll see nothing crucial about sending off the communication to their co-workers, the harm in not booking their time on the project... they live far too often at the center of their own universe. You'll need to jump into that center and shake it up a bit.
Play to their pride, their ego and their intellect.
Tell them that it's not enough to have the idea. Their ideas and designs need to be handled in such a way, that anyone on the team can grasp what they have to offer. Their "job" is not just to be brilliant, but to make the work around their idea just as brilliant. "What good is the great design if we can't bill for it?" Accounting needs to know. "The trade show idea is awesome, but you're going to need 10 people to pull it off, right?" Set up a team e-mail to let them know how awesome it's going to be. "You idea was crucial to winning that piece of business, but we're going to lose it if we're not on time." You've got to take care of your AE.
Set up a check list.
If you let a task go too long, it's gone. Is their a project list, and can a box be checked? Are those boxes chronological? Something this simple can be a real help. People who can fill up a blank sheet of paper with ingenious thoughts and designs, seldom see a start and stop to their work. They're on to the next thought. Give them an official box to check —literally. It will be their "I have made fire" moment.
Do it now.
Creative people may often be disorganized, but they typically are good at playing "hot-potato". In your correspondence, don't allow latitude on executable ideas or tasks. Be specific (we understand deadlines - you just know that the creative will use every last second of it - so "cheat" a little and demand your deadline an hour to a day in advance) and give a clear direction of what and where something has to go. By doing so, you'll allow them to work within a framework that's comfortable for them and you may actually find some peace in your work place.
When all else fails...
Have them explain how their 2% inspiration is going to make a 100% success. Honestly. They most likely see the brilliance of their own thought. They may think that it's enough for something to succeed. You know that just isn't the case, but it hasn't been their job to truly understand that fact. They can and they must. Giving them ownership of the full process may get them to cow-tow a bit better to the hard work of the paper work and communication that should accompany every project running through your company.
...or maybe they'll simply hang out their own shingle, in which case, they're no longer your problem, and you'll have the satisfaction of knowing that they are paying their penance because they finally have to manage the whole process themselves.
