Although we don't believe in timing the market or panicking over daily movements, we do like to keep an eye on market changes -- just in case they're material to our investing thesis.

Yesterday's concerns about the state of the economy turned into resounding optimism today, as stock markets soared in response to a bigger jump in job creation during October than economists had expected. The bullish sentiment was especially obvious in shares of Arena Pharmaceuticals (NASDAQ:ARNA), Santarus (NASDAQ: SNTS), and Universal Display (NASDAQ:OLED), which all posted double-digit percentage gains. Let's look at each of these stocks to see what sent them soaring today.

Arena Pharmaceuticals climbed more than 17% in the wake of the company's third-quarter earnings report. Revenue soared by 140%, although the company's net loss widened from year-ago levels. Much more importantly, though, Arena announced that it would expand its marketing and supply agreement with Japan's Eisai for its Belviq obesity drug, with Arena receiving an upfront $60 million payment in exchange for exclusive commercialization rights nearly worldwide, with the exception of five countries. In the U.S., Eisai will double its sales force in an effort to reach 65,000 doctors nationwide, and will also launch a magazine ad campaign. Investors clearly hope that Eisai's redoubled effort will boost sales, and that Arena will receive further milestone payments under the agreement.

Santarus led the gainers list with a nearly 38% jump after biotech peer Salix Pharmaceuticals made a $32-per-share bid to buy the company. With Santarus shares closing just $0.05 below the buyout price, investors seem to believe that the $2.6 billion proposed deal is the best exit strategy for the company after it got its Uceris treatment for ulcerative colitis approved earlier this year. Salix also advanced, showing that investors believe that the acquisition makes sense in the context of Salix's efforts to bolster its own development pipeline.

Universal Display gained almost 26% after reporting an unexpected profit for the third quarter, with revenue beating consensus estimates by about 50%. The maker of organic LEDs has been working for years to boost the commercial use of its innovative products in smartphones and large-screen displays, and finally, commercial launches are starting to ramp up sales. Universal Display also boosted its full-year 2013 sales guidance by as much as 15% above the top of its previous range, leading investors to conclude that the acceleration in its growth is real.