Avinger Inc. closed an underwritten public offering for gross proceeds of about $18 million.

The company issued about 18,000 shares of series B preferred stock, convertible into about 9 million common shares, and warrants to purchase about 18 million common shares as part of the offering.

The series B stock is convertible into shares at a conversion price of $2 per share. The series B preferred stock and the warrants are immediately separable and will be issued separately.

Redwood City, Calif.-based Avinger plans to use the net proceeds for working capital and general corporate purposes, and may also use a portion to resolve pending legal proceedings.

Ladenburg Thalmann & Co. Inc. acted as sole book-running manager for the offering.

Separately, the company's lenders CRG LP and certain of its affiliated entities converted $38 million of debt into the company's series A convertible preferred stock.

Avinger makes image-guided and catheter-based systems for patients with peripheral arterial disease.