Move Object Forward Click, Move Object Back again on another Click

I want to move a gameobject forward and back when I click on it. However I Also want to Animate the movement, when I use lerp to animate it jumps backward and forward as it is in the Update...Am I on the right track? This is the original code (just makes object change its location):

 private var toggle : int = 1;
 var Active : boolean;
 var BlockDistance : int = 1;
 
 
 function Update(){
 
     if(toggle == 1) {
         Active = false;
         }else{
         Active = true;
         }
 if(Active == true) {
     transform.localPosition = Vector3(transform.position.x,transform.position.y,BlockDistance);
     }else{
     transform.localPosition = Vector3(transform.position.x,transform.position.y,0);
     }
 
 
 }
 
 
 function OnMouseDown() {
     toggle = (toggle + 1)%2;
     }
 
 // Needs to be on a mesh collider 

This is where I'm up to...it can't complete the lerp movement:

 var MovePerSec : float = 1; 
 
 
 static var end : Vector3;
 end = Vector3(transform.position.x,transform.position.y,BlockDistance);
 static var start : Vector3;
 start = Vector3(transform.position.x,transform.position.y,0);
 
 function Update(){
 
 
 
     if(toggle == 1) {
         Active = false;
         }else{
         Active = true;
         }
 
 if(Active == true) {
 
     StartCoroutine("del", 2.0);     
     }else{
 ppp();
     }
 
 
 }
 
 
 
 function OnMouseDown() {
     toggle = (toggle + 1)%2;
     }
 
 function del () {
 transform.position = Vector3.Lerp(start, end, Time.time * MovePerSec);
 }
 function ppp () {
     transform.localPosition = Vector3(transform.position.x,transform.position.y,0);
 }
 
 // Needs to be on a mesh collider