NEW YORK ( TheStreet) -- Pandora Media ( P) shares were jumping more than 9% to $18.73 in afterhours trading after the biggest online radio service beat first-quarter revenue expectations. The company's revenue outlook also topped expectations as its mobile advertising sales accelerated and the company added more subscribers during the quarter. "Pandora continues to expand its mobile leadership," stated CEO Joe Kennedy, who announced in March that he planned to step down after a successor was found. "Mobile listening hours and mobile ad revenue reached record highs, with growth in mobile ad revenue exceeding growth in mobile listening hours. During the quarter, we successfully implemented a mobile listening limit, enabling us to manage our content acquisition costs with minimal impact on listenership or revenue growth. Pandora's subscriber base surpassed 2.5 million, adding more net new subscribers in the quarter than in all of fiscal 2013, giving Pandora the largest US streaming subscriber base of any music service." During the first quarter, mobile revenue grew 101% year-over-year to $86.7 million, outpacing mobile listener hour growth, which grew 47% year-over-year. Also, Pandora One subscribers surpassed 2.5 million, adding over 700,000 net new subscribers in the first quarter and growing 114% year-over-year. Total listener hours grew 35% to 4.18 billion. Content acquisition costs were also managed down during the quarter, with these costs making up 66% of revenue, down from 69% the same period last year. The company predicted second-quarter results ranging from loss per share of 2 cents to a penny a share in profit, on revenue of $155 million to $160 million. The Wall Street earnings target is currently 2 cents a share on revenue of $149.95 million. Pandora estimated that results for the fiscal 2014 spanning from loss of 2 cents a share to earnings per share of 8 cents, on revenue of $615 million to $635 million, vs. the consensus estimate of 2 cents a share on revenue of $618.10 million. For the first quarter, Pandora booked an as-expected loss of 10 cents a share on a 58% increase in revenue from a year ago to $128.5 million. Analysts, on average, predicted revenue of $123.96 million. Follow @atwtse -- Written by Andrea Tse in New York >To contact the writer of this article, click here: Andrea Tse.