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 biopharmaceutical company Opko Health (NASDAQ:OPK) dropped as much as 11% after a top executive sold 50,000 shares of Opko stock.

So what: In order to stem the assumed panic that, after a big run, insiders were cashing out, Opko's management noted that only Adam Logal -- its vice president, chief accounting officer, and treasurer -- sold 50,000 shares to "address pressing family circumstances." According to the press release, no other officers or directors have sold or have contemplated selling shares of the company within the last 12 months.

Now what: Sales of Opko's diagnostic and pharmaceutical products are expected to rise by better than 50% in 2013, according to estimates, but, with a valuation over $1.9 billion, I'm having trouble seeing the same optimism as investors. I wouldn't read too much into Opko's directors' buy and sell indications, but would instead wait for Opko's guidance to dictate the proper course of action for the share price. Based on what I'm seeing (i.e., losses expected throughout 2013), I find a hard time supporting further price appreciation from here.

Craving more input? Start by adding Opko Health to your free and personalized watchlist so you can keep up on the latest news with the company.

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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