Ideational progression

I had an idea for a screenplay yesterday about a guy whose megalo-paranoid personality gets so out of control that he thinks the local book and film critics are somehow reading his novel as he writes it and criticizing it in their articles about other books or films. He draws out their analyses to mean something about his writing, and it is driving him insane. Actually, that's the middle part of the story, while he's living in his former boss's basement trying to write a novel. He hides out because he thinks everyone hates him, when in fact they find him endearing if often frustrating for his paranoia and gruffness. He'll be a kind of Harvey Pekar, but slightly delusional.
The idea actually grew from an initial thought about a character that gets totally disillusioned by reading critics of other people's writings while I was reading some seriously harsh film reviews in the Globe on Friday. The movie's they were reviewing undoubtedly deserved the drubbing they got, but man, Burr and Morris were in slash and burn mode. I can feel for them. I mean having to go see every movie that comes out and try to come up with something intelligent to say about it, forget about it. Anyway, then I thought I might try to incorporate the idea into the Rebel W/out a Cause storyline, but that story's just too full as it is, so the idea was just kind of hanging around.
Then I was at home dancing in my living room to the Dennis Brown Anthology that I just got, and the kernel of the story hit me as this character idea. I then spent the next hour or so flushing it out a little bit to a slight 3 act structure. I want it to end with him finally pushing beyond the paranoia and writing his book, which is maybe rejected by editors or poorly received. Maybe he goes on a book tour and has to defend himself against the kind of criticism he was afraid of, but because he actually wrote the book he doesn't care anymore. Something along those lines. Not a totally happy ending, but he comes out with his own unique brand of success, which gives him a dignity.