Full Idea
Reason itself contains the origin of certain concepts and principles, which it derives neither from the senses nor from the understanding.
Gist of Idea
Reason contains within itself certain underived concepts and principles
Source
Immanuel Kant (Critique of Pure Reason [1781], B355/A299)
Book Reference
Kant,Immanuel: 'Critique of Pure Reason', ed/tr. Guyer,P /Wood,A W [CUO 1998], p.387
A Reaction
You might say that these principles are known 'by the natural light' rather than being innate, but if they are not even 'derived from the understanding', that seems to leave them innate, which is a classic hallmark of a rationalist philosopher.