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 BJ's Restaurants, (NASDAQ:BJRI) dropped as much as 10% early Friday after the company announced preliminary fourth quarter results that left a great deal to be desired and caused the company to be downgraded by investment brokerage Wunderlich Securities.

So what: Quarterly revenue rose roughly 7.1% year-over-year to $213.9 million, helped both by the opening of 11 new restaurants and a comparable store sales increase of 1.2%. Analysts were modeling slightly higher sales of $214.3 million.

Separately, Wunderlich analyst Robert Derrington also downgraded BJ's Restaurants from "Buy" to "Hold," and simultaneously reduced his price target from $56 per share to $50 per share.

Now what: All of these issues being said, its important for long term Foolish investors to have some perspective on this move. First, keep in mind Derrington's new price target still represents a 16% premium to BJ's current stock price of roughly $43 per share. What's more, BJ's comparable store sales results were actually stronger than the company told investors to expect when it announced earnings in late October. At the time, management said October comps were trending in the meager 0.5% range, and warned of continued pressure on average check levels until at least the end of the first quarter of 2015.

So it's no surprise BJ's Restaurants CEO Greg Trojan insisted they are "pleased" with their top-line results today. He elaborated, "The steady progress we made in 2014 in reigniting comparable restaurant sales and managing our business provides us with a solid platform to begin fiscal 2015." 

All things considered, long-term BJ's Restaurants investors shouldn't be alarmed by today's drop.