What happened

Shares of TransEnterix (NYSEMKT:TRXC), a fledgling robotic surgery company, rose an impressive 125.9% in the first half of 2018, according to data from S&P Global Market Intelligence. The much better than expected commercial launch of its Senhance robot-assisted surgical system keeps giving investors reasons to cheer.

So what 

TransEnterix reported a slight profit in the first quarter of the year, but that's only because it divested a previous robotic surgery system that never got off the ground. Nevertheless, some black ink below the bottom line and a handful of Senhance system sales in the important U.S. market perked up the company's already enthusiastic shareholders. 

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TransEnterix stock also received some lift when the company announced the Food and Drug Administration had cleared the Senhance system for use in two more common, minimally invasive surgical procedures -- hernia repair and gallbladder removal. Since the system is already approved for use in the approximately 1.5 million colorectal and gynecologic surgeries performed each year, the inclusion of the new indications effectively doubles the number of procedures that could be performed with the assistance of a Senhance.

Now what

If TransEnterix stock is going to continue climbing, the company needs to show investors that the systems it's already placed aren't just going to sit idle. Predictable, recurring revenue from selling the consumable tools used during each procedure has made industry peer Intuitive Surgical a top stock.

TransEnterix recently announced it sold four Senhance systems worldwide during the second quarter of 2018, which is twice as many it sold during the previous three months. The company has already announced preliminary sales figures for the second quarter of between $6 million and $6.3 million, which would be a huge improvement over the $4.8 million recorded during the previous quarter. If instrument and accessory revenue makes a similarly large leap, the second half of the year could look a lot like the first.

Cory Renauer has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.