Iowa was one of his weaker states.
http://freerepublic.com/focus/news/3378750/posts?page=22#22
Now as I pointed out, this is from polling data collected over several months. Cruz held a lead in Iowa even at the time, however the Western states were led mostly by Carson.
Carson has faded since then.
I really don’t know who might benefit more - Trump or Cruz.
So basically, Cruz blew his wad on Iowa