Insiders are buying at every opportunity.http://www.insidercow.com/history/company.jsp?company=TNGN
I think some of the shares were PRI don't know if they would show on the regular volume charts.
How is this so volatile on such little volume? Non of that insider activity is reflecting in the daily movement. They are using the 30-day option from TNGN to buy stock at $5 per share.