Image source: Getty Images.

What happened

Last month, shares of Fitbit (FIT) popped 13%, according to data provided by S&P Global Market Intelligence. Investors were happy to see the company boost revenue by more than 46% and device sales skyrocket by nearly 27% year over year.

So what

Fitbit has fought back against rising wearable tech rivals like Apple (AAPL 0.01%) by dumping tons of cash in into its research and development program (a 162% increase year over year last quarter) and increasing sales and marketing spending by 70%. 

All that spending evidently paid off in the second quarter, with revenue jumping to $586.5 million and device sales rising to 5.7 million. The company said most of the revenue came from its new devices, the Blaze and the Alta (and their accessories), which made up 54% of all revenue in the quarter. 

Fitbit said in press release that two-thirds of the Blaze and Alta purchases were from new customers, which likely impressed investors who may have been worried about the company being able to bring in new customers in an increasingly competitive wearable tech market.  

But while investors loved seeing revenue and device sales spike, it came at the expense of profits. Earnings per share fell by 57% year over year on a GAAP basis. 

Now what

Fitbit is expected to release more products later this year to keep up its aggressive product push, and that could help the company as it heads into the typically lucrative holiday season. But while Fitbit is the undisputed king of wearable tech right now, there's still plenty to be concerned about as Apple continues to muscle into the space. Fitbit's fate is somewhat tied to Apple's moves, and it's still unclear if the company will be able to fight off the Apple Watch maker over the long term.