vaxart shares plummeted at the start of trading after the company said its public offering had been priced for gross proceeds of 15 million the stock opened 266 lower at 91 cents shares are down 75 over the past 12 months the clinicalstage biotechnology company said just before the market opened that it will offer 16 million shares and has granted its underwriter a 30day option to buy up to an additional 24 million shares the proceeds will be used for general corporate purposes capital expenditures working capital and other expenses