Pandora Media Inc. said first-quarter revenue grew 58 percent to $128.5 million on the strength of mobile advertising and new subscribers to the online streaming music service.

Mobile revenue on a non-GAAP basis nearly doubled in the quarter to $83.9 million.

"The mobile cap they put in place appears to working - it's driving lower content costs and additional subscribers," said Aaron Kessler, an analyst with Raymond James.

Shares of Pandora jumped 9 percent in extended trading after closing at $17.16 on Thursday.

Pandora, whose revenue comes mainly from advertisers, introduced a cap of 40 hours for free listeners on mobile devices. Subscription is required beyond that limit.

Mobile is an important revenue source for Pandora as more people choose to listen to music on smartphones.

Pandora on Thursday it had a net loss of $28.5 million, or 16 cents per share, compared with a loss of $20.2 million, or 12 cents per share, in the year-ago period.

Adjusted for items, Pandora had a loss of 10 cents per share that matched analysts' average estimates according to Thomson Reuters I/B/E/S.

Non-GAAP revenue of $128.5 million includes $3 million related to the mobile subscription service. Analysts had expected $124 million.