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 biotech Amarin (NASDAQ:AMRN) plummeted 20% today after announcing plans to hire a sales force for the launch of its cholesterol-reducing fish-oil pill Vascepa.

So what: The start of an independent sales force, coupled with a $100 million non-equity financing, suggests that Amarin will have to launch Vascepa on its own and that a buyout is no longer on the horizon. Of course, on a conference call CEO Joe Zakrzewski insisted that "all options are still on the table" and that "partner discussions were still active," giving Amarin bulls a glimmer of hope that a deal is still possible.

Now what: Unfortunately, Amarin still isn't sure when the Food and Drug Administration will issue a ruling on Vascepa's New Chemical Entity, or NCE, status, adding even more uncertainty to the situation. Given that the stock will continue to move wildly on news or speculation tied to the NCE status, as well as management's strategic talks, only biotech-savvy bargain hunters should consider jumping in at this point. While Amarin's upside remains juicy, the volatility and downside might be too much for average Fools to handle.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.