While Fools should generally take the opinion of Wall Street with a grain of salt, it's not a bad idea to take a closer look at particularly stock-shaking analyst upgrades and downgrades -- just in case their reasoning behind the call makes sense.

What: Shares of FireEye Inc (NASDAQ:FEYE) popped 5% today after Goldman Sachs initiated coverage on the cybersecurity technologist with a buy rating.

So what: Along with the bullish call, analyst Matthew Niknam planted a price target of $42 on the stock, representing about 24% worth of upside to yesterday's close. So, while momentum traders might be turned off by FireEye's sharp pullback in recent months, Niknam's call could reflect a sense on Wall Street that its growth prospects are becoming too cheap to pass up.

Now what: Goldman listed several reasons why FireEye's risk/reward trade-off is particularly attractive at this point:

(1) FEYE's position as the market leader in fighting APTs positions it well in the current market environment.... (2) Following significant investor concern around weaker product revenue growth in 1Q14, we expect growth to reaccelerate in 2Q14, following a wave of recent product launches, and (3) we expect concerns around FCF burn to moderate, as we expect trough levels in 2014 before an above consensus ramp in 2015. Finally, given its limited scale and global ambitions, we believe the company may be a beneficiary of industry consolidation over time as part of a larger, scaled entity which can reap greater efficiency with FEYE in its fold.

Given Goldman's solid stock-picking track record -- currently ranked in the top 15% of our CAPS community -- tech-savvy contrarians might want to take a closer look at FireEye.