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 Red Robin Gourmet Burgers (NASDAQ:RRGB) were looking tasty today, gaining as much as 10% after serving up an impressive quarterly earnings report.

So what: The casual-dining chain topped earnings estimates by $0.11, with a profit of $0.77 a share, but revenues came up a bit short in the quarter, as sales grew 6.5%, to $238.3 million, below projections of $239.4 million. Same-store sales ticked up 4.3% on a 5% growth in average ticket, due to a price increase, as guest count decreased 0.7%.  Management also said it expects to open 20 restaurants during the rest of the year, increasing its company-owned base by 6%.

Now what: While this was a strong earnings beat, the reason for it was almost entirely the increase in prices, which is not sustainable. The decrease in customer traffic is also concerning, and the company sees a full-year comparable sales increase of just 3%, meaning the second half of the year should be significantly weaker. I'd expect analysts to bump up their estimates after the 44% increase in profits, but I'm not sure if Red Robin will be able to deliver a repeat performance. A P/E ratio of nearly 30 also seems steep for a company with just 6.5% top-line growth.