Antibiotics developer Cempra (NASDAQ: CEMP) is on the hunt for more capital.

The Chapel Hill company plans to offer and sell shares of its common stock, the company announced Thursday after the markets closed.

But the company gave no indication Thursday of just how much it intends to raise.

A prospectus filed with the Securities and Exchange Commission did not list the number of shares or an offering price and Cempra said in a statement that there can be no assurances of the size or the timing of the offering.

Cempra did say it will pursue the stock offering through an existing “shelf registration.” Cempra’s most recent shelf registration was filed in March. Such filings made in advance of a company needing to raise capital. But with much of the paperwork already done, a company can pull the filing “off the shelf” and raise money as needed.

In the March shelf filing, Cempra outlined plans to raise up to $100 million but that figure is just a high mark. Cempra could sell securities in any amount up to $100 million, if it even raises money at all.

Cempra’s shares closed Thursday at $7.95 but were up to $8.13 per share in after hours trading.

Cempra is coming off two major wins in the last month.

First, Cempra reached a $70 million licensing deal with Toyama Chemical Co. of Japan for the company’s top antibiotics candidate, solithromycin.

And two weeks later Cempra announced that the Biomedical Advanced Research and Development Authority, or BARDA, awarded the company a contract valued at up to $58 million to develop solithromycin in pediatric applications and as a possible defense against bioweapons.

Cempra said that proceeds from the stock sale would be used to finance planned oral phase III clinical trials of solithromycin studying the experimental antibiotic in community acquired bacterial pneumonia.