Sapheon raised $3.6 million of a hoped-for $10 million in a convertible debt offering it plans to use as working capital, according to a regulatory filing.

Forty-nine unnamed investors participated in the round for Morrisville, N.C.-based Sapheon, which makes the VenaSeal device for treating varicose veins, according to the filing.

In September Sapheon submitted the 1st module it its application for pre-market approval from the FDA for the VenaSeal device, which is designed to seal blood vessels using a special glue.

The company is conducting a U.S. investigational device exemption trial of 242 patients and has a pair of other studies under way in Europe and the Dominican Republic, totaling 108 patients. The VenaSeal device won CE Mark approval in the European Union in 2011.

Sapheon has said it expects to launch the VenaSeal device in the U.S. during the 1st half of 2015 if the FDA grants approval.