San Diego’s Sequenom (NASDAQ: SQNM) says today it hopes to raise gross proceeds of $84 million from an underwritten public offering of 14 million shares of its common stock at a price of $6 a share. Jefferies & Company is the sole book-running manager for the offering. The company, which specializes in biomedical diagnostics, says it has granted the underwriters a 30-day option to purchase as much as 2.1 million additional shares to cover any over-allotments. The offering is expected to close Dec. 7. Sequenom share prices fell by more than 3 percent, or 22 cents, and were trading at about $6.60 at mid-day; trading was more than four times the recent average volume.