Bankruptcy filings tell the tale. From 36,000 customers down to 7500. And those are soon to go away too, since Riverbed hasn't bothered developing their products in several years.
How long will the $100M cash infusion keep the lights on? A few months? Will it be used to pay severance packages? If cash flow was so bad before bankruptcy, who is going to buy bankrupt Riverbed's outdated appliances now? And you can bet all the 7500 remaining customers are looking at alternatives.
At a macro level you have sales going to zero, and support revenue going to zero... you do the math.
I implore you to start interviewing now. The financial vultures are picking away at the corpse of Riverbed. Don't get caught off guard.