Don't get too excited. The last Emerson poll only showed Cruz with a 1 point lead, so even this poll is showing Cruz expanding his lead. And Emerson underestimated Cruz's support in Texas by 14 points, in Iowa by 5 points, etc. So I think a 7-10 point Cruz lead is probably about right, and consistent with the other polls we have seen.
I fully expect Cruz to win WI but 10 pts is really laying it on thick.