AfD got 12.6% of the votes in the last federal election, with a turn out of 76.2%, which translates to 9.6% or less than 1/10th of the German electorate voting for them.
AfD actually did influence German politics and policy making a lot, and public debate even more so, in my humble opinion.
From what I have seen, AfD is also a lot more "broadly extremist" than UKIP, but I am very probably pretty biased, being from Germany and having consumed far more German news than British.
Trouble is, the UK political scene is currently entirely populated by people who lack the competence to realise there is anything wrong with their own strategies. (All of them, including the groups I used to consider ‘my side’).
So, they might be relevant by default.
They are still going under different leadership, focusing on other typical right-wing issues. Depending on how things go with Brexit they might well come back into the limelight this year.