Ann: Autobio $2M Placement in LBT & MicroStreak IP Transfer, page-34

Their total capital at risk would have dropped from 2 million to 500K. They can then deploy the remaining money in other ways rather than have it locked up in LBT, while retaining the upside of the options.
It's a strategy used by US investment banks in CR's with high risk sectors like Biotech, however they try to sell more gradually to minimise the loss on the intial investment.

If this is not the reason for the dramatic decline, then I'm worried that something more sinister is brewing. At least with the above theory the SP should rebound once the selling ends.