Mazda Miata clutch won't disengage, soft pedal?

The car has been sitting for a long time and I just recently started it up again. Before the long period of rest the clutch worked. Now the clutch pedal is really loose and when the car is running it does absolutely nothing when you push it in. I checked the clutch fluid and it was empty so is this just because there is air in the line? What do I need to do?