Wall Street give IsoRay Medical’s (AMEX:ISR) shares a beating today after the company announced that it had sold about $14.7 million in common stock to a pair of unnamed institutional investors.

The Richland, Wash.-based brachytherapy systems maker announced that it sold more than 5.6 million shares of its common stock at a price of $2.60 per share, planning to use the funds for "working capital and general corporate purposes."

ISR shares dropped more than 20% in early afternoon trading, going for about $2.60 apiece as of about 12:45 p.m. The shares may have simply flown too close to the sun, as they are still trading more than 130% higher than they were just 5 days ago and nearly 270% higher than they were 1 month ago.

The offering is scheduled to close on or before March 26.

One analyst at Seeking Alpha warned that the stock his highly over-valued, placing the target price at $1.50 per share.

"The stock has run upwards of 450% in a span of 5 trading days based on nothing of significance," the author, who goes by the name "value investor right now," wrote today. "The company most likely needs to raise additional capital, so further dilution likely."