What happened

Shares of Tandem Diabetes Care (TNDM -0.90%) were up more than 22% as of Friday morning at 10:30 a.m. ET, according to data provided by S&P Global Market Intelligence. The insulin delivery and diabetes technology company's stock closed last week at $24.46, then rose to as high as $30.40 on Thursday and Friday.

So what

The impetus for the big move was the medical device company's announcement after the market closed on Tuesday that it had received Food and Drug Administration (FDA) clearance for its Tandem Mobi insulin pump for patients 6 and older. The Mobi is the world's smallest automated insulin delivery system, according to Tandem, and is controlled from a mobile application and is compatible with continuous glucose monitors (CGMs).

The company said it expects to launch the product later this year. Some of its features include a 200-unit insulin cartridge and an on-pump button as an alternative to phone control. The device is small enough to be hidden in a coin pocket, but it can also be clipped to clothing or worn with an adhesive sleeve.

Now what

The launch comes at a crucial time for Tandem. While there's plenty of growth expected for diabetes care, Tandem also has plenty of competitors. In the first quarter, the company reported revenue of $169.3 million, down 3.7% year over year, while it had a net income loss of $123.9 million, compared to net loss of $14.7 million in the same period a year ago. The company said it had $519.6 million in cash. One positive is the company's base of installed customers rose 22% year over year, to 430,000. The company makes money not just from the sales of its pumps, but also from the consumables that go along with the pumps, such as cartridges. The company's pump sales are somewhat cyclical, with the fourth quarter, when people have generally met their deductibles, usually showing more sales than the first quarter.