Rigel Pharmaceuticals Inc. priced an offering of 20 million shares at $2 apiece.

The clinical-stage biotechnology company will raise approximately $40 million in gross proceeds to fund research and development activities, among other things.

Rigel also granted the offering's underwriters a 30-day option to purchase up to an additional 3 million shares.

The offering is expected to close by Feb. 3

Jefferies LLC, Piper Jaffray & Co. and BMO Capital Markets are acting as the joint book-running managers for the offering, while H.C. Wainwright & Co. LLC is acting as lead manager.