Theoretically there really isn't any dilution in that if you choose not to purchase shares and or warrants you pay nothing more. Your shares do diminish by 90% but the share price is now ten times what it currently is. The rub is that the PPS generally starts falling shortly after a RS.
Basically NEPH is offering (if my math is correct) current shareholders the opportunity to buy additional shares at 91 cents a share after all options are exercised.