Could be a lot of reasons, but stocks that don't have much backing yet are being held in size by sharks (eg Blum Capital et al) and sharpies (eg spec takeover funds, quant funds) have been and will continue to be subject to selling blitzes since early August and IMO that trend will continue through October. AVID IMO is additionally directly disadvantaged -- its CEO was pushed out w/o a strong permanent replacement, the sagging economy is resulting in loss of advertising revenues at their TV station/network customers, and more.
A final possible factor is Wall Street cannibalization. To wit, when a big holder like a mutual/hedge/quant/spec fund is bleeding in the water, there are other groups on Wall Street that move in for the kill. In that case, they are perfectly capable of shorting/dumping their prey's holdings like AVID as an indirect means of weakening their real prey. There are carnivores on Wall Street for all seasons and all reasons, and if it comes down to survival amongst themselves you will be seeing weaker carnivore on the menus of their betters.
I could have sworn I saw a negative ANALyst note, but as usual with Yahoo they wipe out the newswire ref the next day or two. What I recall was negativity on future orders to the TV industry. You might ask around about ANALysts notes on the board here and see if anyone has it.