Several factors should be taken into consideration.
AMRI's low trading volumes lead to higher volatility. Up until recently, volume has been low. Recently, price rises on some days were accompanied by decent volume.
Why do I mention this? Because volume demonstrates a solid trend one way or the other. My drinking buddy fund manager has a Bloomberg terminal and that includes Bloomberg's patented Money Flow feature. Basically, it boils down to measuring each trade and the price at which it was executed. Volume + Price Change = Money Flow. Stronger Money Flow can be equated with a stronger market sentiment.
Prior to last week, on most days that AMRI cracked the 150k trading level, there were more sellers than buyers.
Another factor is that on many days, especially lower volume days, AMRI seems to trade in sympathy with these benchmarks, with Yahoo ticker in parenthesis: Nasdaq Biotechnology (^NBI) and Nasdaq Health Care (^IXHC) . Punch 'em in and compare.