The link you provided shows 3.8 mm shares sold by insiders. 3.3 mm of those were sold by Resolute Fund Partners and 0.357 mm were sold by JZ Capital Partners Ltd. These are classified as "insiders" because they were holdings of beneficial owners, which is to say owners that held more than 10% of the shares of TAL at the time of the sale. However, they are fund management companies unaffliated with TAL who happen to own large stakes. You may take their sales as a cue for you to sell if you like, but for clarity sake it should be pointed out that over 3.6 mm of the 3.8 mm shares of insider sales were not sold by actual insiders at the company itself, but rather were sold by institutional fund managers who happen to hold large stakes. I look at that very differently.
I sold mine about a buck cheaper than where it is now, and wishing I hadn't. The recent dip to $40 had me concerned. If we get another dip to that area I'll scale back into the stock. Be careful if it makes it to $45.