please help me take json data "price_usd"
https://api.coinmarketcap.com/v1/ticker/bitcoin-cash/
[
{
    "id": "bitcoin-cash", 
    "name": "Bitcoin Cash", 
    "symbol": "BCH", 
    "rank": "4", 
    "price_usd": "338.53", 
    "price_btc": "0.121547", 
    "24h_volume_usd": "189098000.0", 
    "market_cap_usd": "5579888431.0", 
    "available_supply": "16482700.0", 
    "total_supply": "16482700.0", 
    "percent_change_1h": "-4.29", 
    "percent_change_24h": "-23.79", 
    "percent_change_7d": "0.43", 
    "last_updated": "1501831807"
} ]
<?php
$json = file_get_contents('https://api.coinmarketcap.com/v1/ticker/bitcoin-cash/');
$data = json_decode($json, TRUE);
$price_usd = $data["price_usd"];
echo $price_usd;
?>
The php script got nothing
 
     
    