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

What: Shares of inverter manufacturer Enphase Energy Inc (NASDAQ:ENPH) dropped as much as 14% today after the company reported underwhelming first-quarter earnings.

So what: Revenue jumped 50% from a year ago to $86.7 million on 162 MW of microinverters sold. Net loss for the quarter was $6.3 million, or $0.14 per share, up just slightly from a year ago. On an adjusted basis, the loss was $0.07 per share, a penny better than estimates. Management said that revenue for the second quarter would be $100 million to $105 million, toward the low end of analysts' $104 million estimate.  

Now what: The quarter's results may have topped estimates, but there were much higher expectations from investors hoping for a big impact from battery storage or a booming solar market. Instead, losses continued and there are more questions than answers about whether or not Enphase Energy can ever be a big player in energy storage, or even be a profitable inverter supplier.

Unless Enphase Energy makes its way into a business where it can maintain a sustainable competitive advantage and a high margin, I don't see a reason to buy the stock. There's a lot of potential there, but as a supplier of a middling component in a solar power system, I don't see how Enphase Energy becomes the big value-adder that investors once hoped it could be.