Select Comfort Corp., the Plymouth-based maker of adjustable-firmness mattresses, said Monday morning it will likely miss it internal sales goals for the first quarter. The company said in a release that has experienced below-plan sales since Feb. 1.

In a company statement Shelly Ibach, president and CEO, Select Comfort said "We believe this is a short-term issue associated with accelerated changes made to our media-buying strategy, and we are making the necessary corrections to both media buying and near-term expenses."

Shares of Select Comfort were fell $3.21, or 15.6 percent, to $17.31 in early trading.

The company does not provide quarterly financial guidance and does not plan to provide additional comment on sales until it releases its first quarter financial results on April 17th.

Analysts who cover the company were expecting 2013 first quarter sales of $306 million.

Select's sales for the first quarter ended March 30, 2012, were $262.4 million and sales for the year ended Dec. 28 were $935 million.

Patrick Kennedy • 612-673-7926