Shareholders of Catalyst Pharmaceuticals (NASDAQ: CPRX) got a nasty shock on Jan. 23 when the company reported that a competitor, Teva Pharmaceutical Industries (NYSE: TEVA), was planning to make a generic version of its only marketed drug, Firdapse. With Catalyst's shares falling 30% in a day before slightly recovering, it's clear that the market is interpreting Teva's actions as severely threatening, and it's reasonable for investors to wonder if it's time to start looking for the door. First, let's take a moment to understand what Firdapse means for Catalyst Pharmaceuticals.