What happened

After Tandem Diabetes Care (TNDM 1.25%) posted a 42% year-over-year increase in sales during the first quarter, its shares are 18.5% higher as of 11:15 a.m. EDT today.

So what

Tandem Diabetes, which makes touchscreen insulin pumps for diabetics, today unveiled preliminary first-quarter results showing growing demand for its lineup.

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IMAGE SOURCE: GETTY IMAGES.

Specifically, management reported that insulin pump shipments jumped 56% from last year to approximately 4,400 pumps and that, as a result, Tandem Diabetes' sales went up to $27 million. 

The growth benefited from increased sales of its t:slim X2 insulin pump. In its fourth-quarter earnings conference call, management cited the successful launch of integration with Dexcom's G5 Mobile continuous glucose monitor and remote PC functionality as the key drivers of demand for the t:slim X2 pump. 

Tandem Diabetes also updated investors on its balance sheet. It finished March 2018 with approximately $81.9 million in cash, cash equivalents, and short-term investments, including about $64.2 million in net proceeds from an equity financing it completed in February and $6.5 million in net proceeds from warrants that were exercised in the first quarter of 2018. 

Now what

The revenue acceleration is good news because the market for devices that help manage diabetes is becoming increasingly competitive due to new product launches, such as Medtronic's (MDT -1.41%) artificial pancreas. Rising revenue is also important to Tandem Diabetes' long-term survival because the company is yet to turn a profit. Last year, its GAAP operating loss was $62.9 million on $107.6 million in revenue.

Tandem Diabetes plans to report official first-quarter results on April 26, and while it's unlikely those numbers will change meaningfully from these preliminary results, it may still be worth tuning in to see if the company offers new insight into its full-year forecast. Currently, it's guiding for full-year sales of between $132 million to $140 million and a negative operating margin of 35% to 40%.