In this daily chart of MYGN, above, we can see weakness before yesterday's plunge. Prices have been trading below the declining 50-day and 200-day moving averages for some time.
The On-Balance-Volume (OBV) line has been declining since November telling us that sellers have been more aggressive for months. The volume on the gap day was huge and tells you investors really wanted out of this name.
We needed to look at this five-year weekly chart of MYGN, above, to see where support might develop. MYGN has pretty much broken the support from late 2013. All the long-term indicators are aligned to the downside -- a downward sloping 40-week moving average line, a declining OBV line and a bearish MACD oscillator.
How far MYGN will fall is a tough call at this point. It could work lower into the upper teens and if there is a bounce the $24 area will likely cap the upside (the midpoint of the gap).