They have a missile that has the diameter and weight-carrying capacity to carry a nuclear weapon to Israel. They appear to have a program to design a warhead that would fit on that missile. They have a program to produce large amounts of low-enriched uranium, which would give them the raw material to build more than dozens of bombs. I say more than dozens because conceivably it would be even in the low hundreds of bombs. It's hard to look at this without starting to worry that they're planning to in fact produce dozens and dozens of bombs with the characteristic that they could fit on those long-range missiles.
Furthermore, they are testing even longer-range missiles. These multi-stage missiles they are testing would have the range to reach into eastern Europe, but what's more disturbing is that most countries that have learned how to build multi-stage missiles have been able to expand that upwards to the point where they could build an intercontinental ballistic missile. The great technical hurdles are in going to the multi-stage, not in how you ramp up from there to an intercontinental ballistic missile. The fact that Iran is putting so much effort into a multi-stage missile suggests that its ambition may in fact be to acquire intercontinental ballistic missiles, but we have no proof of that.