It is known that the response time for Iron Dome is such that short range and depressed trajectory rockets cannot be intercepted. Longer range rockets, such as the Grad appear susceptible to interception by Iron Dome. Either that, or they will be used on depressed trajectory attacks and thus have their range severely restricted. The extreme reluctance of the IDF to deploy the system over the last year suggests that it does not perform as well as claimed, and that no one wants to burden their budget with an expensive system.
Passport control employees at Ben Gurion airport to strike between 11 A.M. and 1 P.M. (Haaretz)
from the article: Israel deploys Iron Dome missile defense system for first time