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

What: Shares of Zendesk, Inc. (NYSE:ZEN) popped 8% today after Canaccord Genuity initiated coverage on the software development specialist with a buy rating.

So what: Along with the bullish call, analyst Richard Davis planted a price target of $19 on the stock, representing about 23% worth of upside to Friday's close. So while conservative investors might be turned off by Zendesk's emerging nature, Davis' call could reflect a sense on Wall Street that its growth prospects are just too promising to pass on.

Now what: According to Canaccord, Zendesk's risk/reward trade-off is pretty attractive at this point. "Zendesk is a promising, albeit emerging firm that appears set to continue to rapidly win business with firms looking to deploy what we believe is a best-in- class customer engagement platform," said Davis. "Our $19 price target is based on an 8.8x EV/revenue multiple applied to our C2015 estimate of $161M, assuming roughly $55M in prospective net cash and a fully diluted post-deal share count of 77.3M." Given Zendesk's still-speculative business model and suddenly hot stock price, however, I'd wait for a much wider margin of safety before betting on those assumptions. 

Brian Pacampara has no position in any stocks mentioned, and neither does The Motley Fool. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.