I don't understand the expectation that it is management's job to support stock price, particularly in a venture like this? Shouldn't they be focused on executing the science and business plan? Who knows why any insider might buy or sell shares? There could be a million different reasons, irrespective of pps levels.
Why buy at market when you can vote yourself stock options or even stock grants? That may be one reason for not buying.
The bigger concern...why no ownership by ANY "smart money"....like a hedgie or some really smart biotech analyst or private investor? That's the concern I have and have always had...much more so that if AD and ES are buying at market...they don't need any more shares if this works, IF...IF!