What happened

Shares of Red Robin Gourmet Burgers Inc. (NASDAQ:RRGB) climbed 22.7% in the month of May, according to data provided by S&P Global Market Intelligence, after the casual-dining chain delighted investors with solid first-quarter 2017 results.

So what

That's not to say Red Robin's quarter looked stellar on the surface. Revenue rose 4.1% year over year to $418.6 million, as a 1.2% decline in comparable-restaurant revenue was offset by new and acquired locations. That translated to an 18.3% drop in net income to $11.6 million and a 13.6% decline in net income per share to $0.89. But Wall Street, by comparison, was looking for even lower earnings of $0.57 per share.

Naturally, Red Robin stock jumped nearly 20% the following day as investors digested the news.

Red Robin's Burnin' Love burger

IMAGE SOURCE: RED ROBIN GOURMET BURGERS.

Now what

Red Robin CEO Denny Marie Post added that the company has gained share in the struggling casual-dining market, thanks largely to its strategic initiatives to drive sales and traffic. For full-year 2017, Red Robin also now expects earnings per share of $2.80 to $3.10 -- significantly above the $2.76 per share analysts were modeling at the time of the release.

In the end, Red Robin didn't need jaw-dropping growth for its share price to continue to climb. Rather, its rise was a simple case of beating expectations and following with strong guidance. And investors rightly savored every bit of the stock's ensuing gains last month.

Steve Symington has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.