EnteroMedics Inc. is looking to raise $16.5 million in an underwritten offering of class A and class B units.

Each class A unit will sell for $5.31 apiece, comprising one common share and a warrant to purchase another stock for $5.84 within five years from the date of issue.

Class B units are priced at $1,000 apiece and consist of convertible preferred stock and warrants to purchase 188 common shares.

All in all, EnteroMedics expects to issue 751,412 common shares, 12,531 preferred shares and warrants to purchase another 3,111,299 common stock of the company.

The issue is expected to close by Jan. 23.

The offering's underwriters can purchase up to an additional 466,695 common shares and warrants that can be exercised for up to an additional 466,695 shares of the company.

Ladenburg Thalmann & Co. Inc., a subsidiary of Ladenburg Thalmann Financial Services Inc., is the sole book-running manager for the offering.