Ideas don't come easily to me, which might be surprising if you thought that all artistic types are virtually brimming with some vision or other, ideas spewing all over the place.
And the ones that come don't usually stay for the party. If it's an interesting thought, I'll usually ponder that for a little while, and then discard it in the face of more immediate problems at work, like figuring out why some invoice for a sh*t-ton of money didn't get paid.
The good ideas--the best ones--the ones I actually do something with--come back again. After six months or so, but they do come back. It's hard to say exactly what will be a good idea: an offhand comment on an email, watching my cats play, a lyric to a song I haven't heard in ages. Inspiration comes from the weirdest places.
I suppose, if I were any better at capturing ideas, I'd be a lot more prolific. As it is, well, I don't work at a lab because I like breaking the rules.