Hi blackthumbkate and
to ATP! Your lilies (true lilies, genus lilium) did not die, they just went dormant for the off season. The foliage and stem die back and the bulb rests to return in the spring.
They look crowded and would grow best planted in the garden but you probably should wait until fall to transplant them. You can ask questions about true lilies on the lily forum here
http://garden.org/forums/view/...
True lilies are different from daylilies (genus Hemerocallis). Stick around and you can learn a lot about both!