The company may have done a large stock buyback for 3 million shares on Thursday. This would lower total float to 10.7 million shares. The CEO with the help of private equity could very easily buy the company then.
Rbcn is selling at 30c on the dollar and any news, will force the 3 million shares that are short. They could sell the co to CREE or one of the Asian co looking for IP. They could do a massive buyback or they co beat earnings