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 Inovio Pharmaceuticals Inc (NASDAQ:INO), a maker of synthetic vaccines targeted at treating infectious diseases and cancer, plummeted as much as 26% after reporting its second-quarter financial results after the bell on Friday.

So what: So much for heading into the weekend on a positive note! For the quarter, Inovio reported revenue of $786,000 compared to $436,000 in the year-ago period, but it also levied a wider loss of $0.06 per share on shareholders relative to its $0.03 per-share loss last year. Operating expenses actually fell 10%, working in the company's favor; however, Inovio's huge share price appreciation caused it to take a charge related to its stock warrants, which pushed losses higher. In addition, once the quarter ended, Inovio reported that it sold some 4.2 million shares under its at-the-market sales agreement and exercised warrants to purchase almost 5.3 million shares of stock.

Now what: I'm pretty sure everyone under the sun knew this rally was bound to come crashing back to Earth. My biggest concern with a company like Inovio isn't its ability to innovate so much as it is its ability to find a buyer for its vaccines. Infectious disease vaccines are growing more competitive and most governments and hospitals simply aren't buying enough of the product to make the ongoing research profitable for many of these small biotech firms. With the company's accumulated deficit over the past 30 years now at nearly $250 million, and its outstanding share count having grown by a 12 over the past decade because of dilutive share offerings, I would strongly suggest looking elsewhere for investing ideas in the biotech sector.

Fool contributor Sean Williams has no material interest in any companies mentioned in this article. You can follow him on CAPS under the screen name TMFUltraLong, track every pick he makes under the screen name TrackUltraLong, and check him out on Twitter, where he goes by the handle @TMFUltraLong.

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