German idealism
Neo-Kantianism refers broadly to a revived type of philosophy along the lines of that laid down by Immanuel Kant in the 18th century, or more specifically by Schopenhauer's criticism of the Kantian philosophy in his work "The World as Will and Representation" (1818), as well as by other post-Kantian philosophers such as Jakob Friedrich Fries and Johann Friedrich Herbart. It has some more specific reference in later German philosophy.
German philosophy
Since the publication of his "Critique", Immanuel Kant has been considered one of the greatest influences in all of western philosophy. In the late 18th and early 19th century, one direct line of influence from Kant is German Idealism.