We are talking about exchange traded call options. A March 5 PTX call gives the buyer the right, but not the obligation, to buy 100 shares of PTX at $5 per share at any time up to the expiration date of the option (the third Friday of the month, in this case March 17).
As the other poster stated, do not mess with options until you are sure you fully understand them. A good place to start would be the following web sites:
I would read through those materials, then if still interested do some simple paper trading over the course of a couple months before putting real money into options.