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 stem cell therapy specialist Geron (Nasdaq: GERN) plunged as low as 17% in intraday trading after it announced plans to raise about $87 million in a stock sale.

So what: Unfortunately for Geron shareholders, the 17.4 million public share offering is being priced at $5 each, representing an 18% discount to yesterday's closing price. Additionally, Geron is giving its underwriters an option to buy another 2.6 million shares, leaving Mr. Market more than enough dilution anxiety to send the stock plummeting.

Now what: I wouldn't be so quick to pounce on today's price plunge. When you couple today's discounted capital raise with the most recent quarter, in which losses widened to $18.3 million on growing expenses, Geron's fundamentals leave plenty to be desired. For my money, profitable big-caps like Amgen (Nasdaq: AMGN), Biogen Idec (Nasdaq: BIIB), and Bristol-Myers (NYSE: BMY), which all sport forward P/E's under 12, seem like much more prudent biotech bets.

Interested in more info on Geron? Add it to your watchlist.

Fool contributor Brian Pacampara owns no position in any of the companies mentioned. Try any of our Foolish newsletter services free for 30 days.

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