Ok - too many posts, tweets, and bearish sentiment about this insider selling. Let’s look at what is really going on here (if you're lazy scroll to the bottom):
Stephen Hoffman – director at ACRX and partner at Skyline Ventures. Skyline distributed 1/3rd of their ACRX shares to investors in their fund recently via an ‘in kind distribution’ – or basically handing the shares over to individual investors rather than cutting them a check. Though they aren’t actually his shares, Stephen is on the Form 4 because he is an insider and representative of the fund. You’ll notice there were multiple Form 4s filed – one showing Stephen as an insider and then one showing the fund itself as a 10% stakeholder. This was one transaction with multiple filings as a means of full disclosure. Regardless, there are a number of reasons this distribution could have happened. One possibility is that approval will be a binary even for the stock and this is a means of giving individual fund investors the choice to hold their ACRX position through that or not.
Mark Wan – director at ACRX and partner at Three Arch Partners. Three Arch has a large number of ACRX securities in several of their funds and recently sold a relatively small amount. How small of an amount? Look at the form 4. There was a total disposition of 10.7% from the 4 funds listed. The "126,153 remaining shares" Yahoo reports is just from one of their smaller funds - Three Arch still owns nearly 10m shares overall. They bought in at less than 1/3rd the current price yet are only taking a little off the table. That’s modest profit taking, not “insider dumping”.
In the end: Hoffman/Skyline didn't sell, they transferred. Wan/Three Arch did sell a sliver (~10%) and are still holding far (like, almost 100x far) more shares than Yahoo is reporting.