Before the Nazi Party came to power, it took part on several elections: 6.4% and 3% in 1924, 2.6% in 1928, 18% in 1930, and 37% and 33% in 1932 (came 1st) and 44% in 1933.

A party doesn't come out of nowhere. It takes time. In 2013 AfD missed the 5%, but not by much. In 2017 has 13% and is the third largest party in Germany. Saying that it'll fizzle out soon is naive at best.