Coinbase isn't supporting it as of now, though it is supported on lots of other exchanges. There's LocalMonero (like LocalBitcoins), Poloniex, Bittrex, Bitfinex, Kraken, HitBTC, Shapeshift, and many other large exchanges support it, however.

I personally use Changelly for conversions; if you want to use my referral link (no cost to you), it's this.

Thanks!