"insiders" doesn't necessarily mean astute investors. Besides, "insiders" sell for a variety of reasons. Could be their real estate taxes are due or they want to buy a Maserati for cash, etc.
Read my comments on the Current SA article about IBM insider sales.
Why not find out the reasons for their sells instead of speculating? What are you, an anal-yst?
I seriously doubt you would ever buy.
If the extent of your due diligence is to make decisions based on what others are doing, then you definitely SHOULD NOT buy. Buy an index fund and sleep peacefully.