Zai Lab (ZLAB) said late Wednesday it has launched a $200 million public offering of its American depositary shares.

The firm expects to grant a 30-day option to its underwriters, including Goldman Sachs and Jefferies, to acquire up to an additional 15% of the ADSs sold in the offering. Each ADS represents 10 ordinary shares.

Zai Lab said it plans to use the net proceeds for general corporate purposes.

The company's shares were down about 8.8% in after-hours activity.

Price: 27.31, Change: -2.64, Percent Change: -8.83