They had a 1 for 4 reverse split not too long ago. That is what affected the options. So, instead of dealing with the standard 100 shares, you are effectively dealing with 100 quarter shares, 25 shares or whatever will make it make sense. I say that because everything else has the 100 multiplier.
e.g. you buy one call with a strike of 2.5 with a ask of .05. That contract will cost you $5 plus commission, If it is exercised, you will get 25 shares for $250. Yes, $10 per share.
Or you can sell a 2.5 put for 1.80 ($180) and if exercised end up with 25 shares for (250-180 =) $70.. A much better deal then the call. That is only $2.8 per share. But if the price of OPXA is higher then $2.50 at expiration, you get to keep the $180 and no stock.
IMHO These options are not a good move unless you miss Vegas.