Full Idea
I distinguish ideas from thoughts. For we always have all our pure or distinct ideas independently of the senses, but thoughts always correspond to some sensation.
Gist of Idea
Thoughts correspond to sensations, but ideas are independent of thoughts
Source
Gottfried Leibniz (New Essays on Human Understanding [1704], 2.01)
Book Reference
Leibniz,Gottfried: 'New Essays on Human Understanding', ed/tr. Remnant/Bennett [CUP 1996], p.119
A Reaction
Leibniz's concept of an 'idea' is quite different from the empiricist notion of them, and strikes me as being much closer to Frege's notion of a concept. On the whole I like the Leibniz account best.