NeuroMetrix Inc. won commitments from institutional investors to buy about $18.7 million worth of its stock — 8,816,521 shares and warrants to purchase up to 8,375,695 additional shares — in a private placement for $2.12 per share.

The Waltham, Mass.-based nerve test equipment manufacturer said the offering is expected to close “later this week.”

It plans to use the cash to bolster its direct sales force in the U.S., boost its profile overseas, pay for clinical trials and get its lead potassium channel blocker compound to a Phase I milestone.