This quote is from an excerpt of a discussion about the craftsmanship and process that is required to take an idea to a remarkable product. Its the reason two people can have an almost identical idea and only one of them turns it into something successful:
… one of the things that really hurt Apple was after I left John Sculley got a very serious disease. It’s the disease of thinking that a really great idea is 90% of the work. And if you just tell all these other people “here’s this great idea,” then of course they can go off and make it happen …
The rest of the quote is here on the Signal vs. Noise blog.