Coroutine isn't entering If statement c#

Hi guys, i'm new to coroutines and im trying to make a simple Ai, it is supposed to follow when in range and lay a trail of nodes and navigate back to start position when the player breaks the range. it gets into the idle IEnumerator but wont then enter the If statement.

 using UnityEngine;
 using System.Collections;
 
 public class shogoth_follow : MonoBehaviour {
     public GameObject target;
     int range; 
     float lockPos = 0;
     bool follow;
     bool hasFollowed;
     float timer;
     bool timerActive;
     public GameObject[] path;
     Vector3 myPosition;
     public GameObject path_Node;
     float speed =  3.0f;
     private float startTime;
     Vector3 startRotation;
 
     void Start () 
     {
         target = GameObject.FindGameObjectWithTag ("Player");
         StartCoroutine("idle");
         range = 10;
         
     }
 
     IEnumerator idle()
     {
 
         if(Vector3.Distance(gameObject.transform.position,target.transform.position)< range)
         {
             Debug.Log ("seen");
             startRotation = transform.rotation.eulerAngles;
             follow = true;
             hasFollowed = true;
 
         }
         else if (Vector3.Distance(gameObject.transform.position,target.transform.position)> range)
         {
             follow = false;
             if (hasFollowed)
             {
                 CancelInvoke();
                 yield return StartCoroutine("backTrack");
                 
                 
             }
         }
         if (follow)
         {
             Debug.Log ("follow state");
             yield return StartCoroutine("chase");
             
         }
         yield return null;
     }
 
     void spawnNode () 
     {
         GameObject newNode = Instantiate (path_Node, transform.position, transform.rotation) as GameObject;
         newNode.name = "pathNode";
         Debug.Log ("path node spawned");
 
     }
 
 
 
     void FindPath()
     {
         int i;
         GameObject[] pathNodes = GameObject.FindGameObjectsWithTag("pathnode");
         path = new GameObject[pathNodes.Length];
         for (i = 0; i < pathNodes.Length; i ++)
         {
             path[i] = pathNodes[i];
         }
     }
 
     GameObject closestPath (GameObject[] targets)
     {
         int i;
         float closest = (path[0].transform.position - transform.position).sqrMagnitude;
         int targetNumber = 0;
         for (i = 1; i < targets.Length; i++)
         {
             float currentDistance = (path[i].transform.position - transform.position).sqrMagnitude;
             if(currentDistance < closest)
             {
                 closest = currentDistance;
                 targetNumber = i;
             }
         }
         return path[targetNumber];
     }
 
     IEnumerator backTrack()
     {
         int i;
         GameObject moveTarget;
         FindPath ();
         for (i = 0; i < path.Length; i++)
         {
             myPosition = transform.position;
             startTime = Time.time;
             moveTarget = closestPath(path);
 
 
             float step = speed * Time.deltaTime;
             transform.position = Vector3.MoveTowards(transform.position, moveTarget.transform.position, step);
 
 
             Destroy(moveTarget);
             transform.rotation = Quaternion.FromToRotation(transform.rotation.eulerAngles,startRotation);
         }
         yield return StartCoroutine ("idle");
     }
 
     IEnumerator chase()
     {
         InvokeRepeating("spawnNode",0,3);
         transform.LookAt(target.transform.position);
         transform.rotation = Quaternion.Euler (lockPos,transform.rotation.eulerAngles.y ,lockPos);
         transform.Translate(Vector3.forward *  Time.deltaTime*4);
     }
 
     void Update () 
     {
 
     }
 }