I want to have a GameObject that has a "hovering" effect when the mouse is over it.

What I'm having trouble with is actually having a color that gradually goes from one color to the next. I'm assuming Color.Lerp() is the best function for that, but I can't seem to get it working properly.

Here's my CubeBehavior.cs's Update() function:

private bool ReachedTop = false;
private float t = 0f;
private float final_t;
private bool MouseOver = false;

// Update is called once per frame
void Update () {
    if (MouseOver) {
        t = Time.time % 1f; // using Time.time to get a value between 0 and 1
        if (t >= 1f || t <= 0f) // If it reaches either 0 or 1...
            ReachedTop = ReachedTop ? false : true; 

        if (ReachedTop) final_t = 1f - t; // Make it count backwards
        else final_t = t;

        print (final_t); // for debugging purposes
        renderer.material.color = Color.Lerp(Color.red, Color.green, final_t);
    }
}

void OnMouseEnter() {
    MouseOver = true;
}

void OnMouseExit() {
    renderer.material.color = Color.white;
    MouseOver = false;
}

Now, I've tried several approaches to making it reach 1 then count backwards till 0 including a multiplier that alternates between 1 and -1, but I just can't seem to get that effect. The value goes to 1 then resets at 0.

Any ideas on how to do this?