What happened

Shares in Nevro Corp. (NVRO 1.66%) are rallying 10.5% at 12:30 p.m. EDT after the company gave investors an early peek at its second-quarter financials,

So what

The company is knee-deep in growth mode following the launch of Senza in 2015, a device that uses neurostimulation of the spinal cord to reduce chronic pain in patients. 

A doctor consults with a patient in a hospital bed.

IMAGE SOURCE: GETTY IMAGES.

In the second quarter, global sales are expected to officially clock in between $77.5 million to $78 million, up from $55.4 million one-year ago. Revenue in the U.S. is anticipated to be between $62.7 million and $63 million when the accounting dust settles.

For the full year, management is reaffirming its target for sales of between $310 million to $320 million. For comparison, revenue was $228.5 million in 2016, up 228% from 2015.

Now what

Marketing Senza hasn't been cheap. Operating expenses grew to $176 million in 2016 from $104 million in 2015, and while the company didn't offer up preliminary numbers on the bottom line today, heavy spending in the first quarter kept the company firmly in the red. 

In Q1, the company's investment in personnel caused operating expenses to come in 70% higher than last year. As a result, its loss from operations was $13.1 million, or $0.50 per share in the period.

While it's good news to see that the company continues to grow quickly, investors shouldn't ignore the fact that sales growth is decelerating. That's not unexpected -- at some point, however, investors will want to see a clear runway to profitability.