Agricultural biotech Ceres Inc. is planning a secondary offering of its common stock that could bring in up to $20 million.

The Thousand Oaks firm will use the funds for general corporate purposes, including working capital. It did not disclose the number of shares to be offered or pricing, according to a prospectus filed Friday with the Securities and Exchange Commission.

Aegis Capital Corp. of New York is acting as the sole book-running manager of the offering.

Ceres is among a handful of companies developing genetically modified sweet sorghum seeds for ethanol crop, and has contracts with mills in Brazil.

But the demand for the seeds has been lower than expected, prompting Ceres to announce in October it would lay off about 20 percent of its workers. The company has yet to report a profit since going public in February 2012.

Ceres reported a net loss of $8.2 million (-33 cents a share) in its fiscal first quarter ended Nov. 30. Revenue plummeted more than 60 percent to $793,000.

Shares closed down 6 cents, or 4 percent, to $1.42 on the Nasdaq.