After popping 15% yesterday after the company released earnings, shares of Dendreon Corp. (OTC:DNDNQ) slipped back 7% today, showing that investors may have sobered up after taking time to digest the earnings news. The company did sell more of its drug Provenge than expected, showing a sequential improvement of 10% to $74.8 million in sales, but in this video, Motley Fool health-care analyst David Williamson reminds investors that this is still down from the $85.5 million for the company last year. He also notes that management has said Q1 of 2014 would more closely resemble Q1 of 2013, which posted the disastrous sales figure of $67.6 million. David stresses how vital sales growth is for Dendreon today, and emphasizes how essential it is for the company to avoid these backslides.