How to use ilaplace on a transfer function

I would like to know how to use ilaplace on a transfer function given the following.

num = [1]
den = [1 1 1]

sys = tf([num],[den]);

ilaplace(sys)

I know that the one below works but I want to know how I could use ilaplace on the above code.

syms s

g = 1/(s^2+s+1)
ilaplace(g)