This little company's scientific breakthrough opened up a whole new sliver of the drug market (although it's still leading the developmental race).Small biopharma story stocks just aren't paying off like they used to. Maybe there are just too many of them, with each one working on a medical breakthrough that's statistically unlikely to even come close to an approval.Every now and then, though, one of these companies defies the odds and gets a new drug on the market. CRISPR Therapeutics (CRSP -2.34%) is one ...