Thousand Oaks-based Ceres, the developer of seed stock for energy crops, said today that it has closed its IPO, selling a total of 5,750,000 shares of its common stock at $13.00 per share. The firm said its underwriters exercise their full option to purchase an additional 750,000 shares of common stock from the company as part of the IPO. Ceres debuted last Wednesday on the Nasdaq Global Market as CERE. The firm's IPO was underwritten by Goldman Scahs & Co., Barclays Capital, Piper Jaffray, Raymond James, and Simmons & Company International. The firm is now trading around $15.08. Ceres is the first, venture-backed Southern California company to hit the market this year.