What: Shares of Aerovironment, (NASDAQ:AVAV) had a rough September, falling 17% after an earnings report that had investors wondering when they would see a turnaround in the company's fortunes.

So what: On the first day of September, Aerovironment reported a loss of $0.24 per share on an adjusted basis, six cents worse than Wall Street expected. That's what started the decline for the stock and it never got any better.

The problem Aerovironment has today is that it's sinking millions into programs like Global Observer and commercial drones that present big market opportunities but no one knows quite when the payback will be or how big it will be. That makes Wall Street nervous and with the company swinging to a loss it's time to start showing some progress on these growth initiatives.

Now what: Aerovironment is playing the long game when it comes to drones and investors have to take quarters like this with a grain of salt. The long-term payoff won't come until years down the road and a single quarter's loss is just the cost of making that investment in growth.

With that said, I think investors need to be cautious just jumping into this stock without knowing the risks. High altitude drones like the Global Observer may not pan out and the company just lost a project to build medium altitude drones for the military. I'm still bullish long-term but risk averse investors may want to wait for more growth on the top and bottom line as a sign that the business strategy is working and it's time to buy the stock.