Full Idea
Fichte said that the thing-in-itself (which both Reinhold and Schulze accepted) is only "a piece of whimsy, a pipe-dream, a non-thought".
Gist of Idea
The thing-in-itself is an empty dream
Source
report of Johann Fichte (Review of 'Aenesidemus' [1792]) by Terry Pinkard - German Philosophy 1760-1860 05
Book Reference
Pinkard,Terry: 'German Philosophy 1760-1860' [CUP 2002], p.107
A Reaction
This seems to be a key moment in German philosophy, and the first step towards the idealist interpretation of Kant.