RVX's share price has on many occassions inexplicably run up by dollars, and I would contend that when real negotiations start heating up behind the scenes we will witness another "inexplicable" run up by dollars per share over a few months or quarters.

When a deal is finally announced, the announced 100% to 200% "premium" will be expressed as a percentage from the new higher share price or the already much higher 30-day average.    

N.B. Synthorx SP nearly tripled in the months leading up to the buy out for 282% of its 30-day moving average. 

Also from the article:  "The biggest premium paid over the period was actually for Tobira, which Allergan bought for $1.7bn in 2016, at a 1,532% 30-day premium; however, this has been excluded as an outlier."