I think it'd be fine, assuming it is a good tire. I had sidewall damage on a set of Michelin pilot sport 4S's. It's the best-of-the-best. It endured perfectly fine.
Look at this guy:
https://www.youtube.com/watch?t=160&v=UgBqXsKNRGs&feature=youtu.be
Toyo At3's with sidewall damage. The guy still goes off-roading with it. Some manufacturers, for some tire lines, over build/engineer their tires. Not all tires are equal, and some will fail where others don't given the same damage. If it's a budget tire, I'd probably replace it. Judging by the damage, if it's a trusted tire, I probably wouldn't worry.
