Companies whose shares are expected to trade actively in today’s session are Pandora Media Inc (NYSE:P), Ambarella Inc (NASDAQ:AMBA), Skullcandy Inc (NASDAQ:SKUL), Sequenom, Inc. (NASDAQ:SQNM), Maxwell Technologies Inc. (NASDAQ:MXWL) and Ann Inc (NYSE:ANN).

stocks to watch

Pandora Media Inc (NYSE:P): The Internet radio firm’s revenues continue to rise briskly. The company won investors’ confidence by demonstrating that its costs are mounting at a much slower pace. However, Pandora CEO Joseph Kennedy is stepping aside. Results handily topped Wall Street estimates. Shares surged 21.48 percent to $14.25 in early trading.

Ambarella Inc (NASDAQ:AMBA): The image-processing chips manufacturer’s fourth quarter profits more than doubled amid solid growth in the network security camera market. Results beat analysts’ expectations. Shares rose 17.88 percent to $14.11 in the early session.

Skullcandy Inc (NASDAQ:SKUL): Though the headphone maker’s 2012 sales soared 28 percent, the company issued a downbeat first quarter guidance. Skullcandy admitted that it made some big packaging mistakes, and couldn’t address trends in the audio category quickly. Shares plunged 18.30 percent to $5.49 in early market trading.

Sequenom, Inc. (NASDAQ:SQNM): The life sciences company’s fourth quarter losses widened as expenses increased and margins continued to weaken. The loss was far greater than analysts’ expectations. Shares tumbled 9.61 percent to $4.08 in early trading.

Maxwell Technologies Inc. (NASDAQ:MXWL): Shares of the power systems and components maker sank 9.87 percent to $8.21 after it announced that it has to restate the results of 2011 and most of 2012. Maxwell said there were errors in timing of recognition of sales from certain distributors.

Ann Inc (NYSE:ANN): The women’s apparel retailer posted 8.7 percent increase in its fourth quarter profits amid strong revenue growth. Same-store sales remained almost flat. After cutting the fourth quarter guidance last month, the company issued above-consensus guidance for the current quarter and full year. Shares gained 6.38 percent to $30.85 in early market.

Another company to watch for is Medifast Inc. (NYSE:MED). Though its fourth quarter profits rose 59 percent, the company issued pessimistic guidance for the current quarter.