Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Optimer Pharmaceuticals (Nasdaq: OPTR) jumped 12% today after positive news from the FDA was released.

So what: The company's experimental antibiotic, fidaxomicin, passed a key test when the FDA agreed with the company's efficacy claims. The drug, which fights life-threatening diarrhea, is headed to an advisory panel Tuesday.

Now what: There are still concerns about safety, as 25.7% of fidaxomicin patients had serious complications, but the market is overlooking that risk. Analysts expect $203 million in sales annually if the drug gets final approval. Good news from the advisory panel could spark another move for the stock. Stay tuned.

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