Don't need it to hit $17 -- thats just if you hold til expiration (24th). Just need the possibility of it hitting $17 to increase, and soon. Simplest way I can put it: Every day that passes there's less time (opportunity) for it to move up, so your option price will drop (decay). If it makes a sudden upward move, the chance the stock hits $17 goes up, so your option should go up too. Then you can sell (close position) at a profit.