there was fear that there was going to be significant restatement of earnings related to philidor (or whatever) and it turned out not to be meaningful. short squeeze.
Sounds like a good explanation but it's just speculation. Even if the "restatement of earnings related to philidor (or whatever)" turned out to be meaningful VRX still could have jumped 5% after a two day 20% sell-off.
It's known as Volatility.

