In my opinion, Natera has a toxic culture. I won't pretend to understand what causes it or keeps it going. All I can say is that I felt this unsettling, gnawing pulse during most of my time there.
In my experience -- after my honeymoon -- I had internal struggles. I desperately wanted to leave, but I also desperately wanted to stay, to improve things and make an impact. The company has a very distinct lure about it, and, I believe, even those within its walls hold on to this hope that the culture is merely a product of "growing too fast" or "being on the cutting edge," and it will turn around soon.
In my opinion, Natera is akin to Theranos. To me, it seems to be a healthcare company run by those without a lot of prior healthcare experience. I truly hope the company doesn't have the same outcome as Theranos.