If you look at the chart you will see that the lower gap hopped over the 200MA. The 200MA is a significant point of resistance to higher prices usually and one that any retail stock trader will be familiar with. So to avoid that wall of selling you simple gap the price up and over it which the market makers did.
There's nothing that says that the lower gap "will" 100% guaranteed be filled. It's all a game of probability and my interpretation of what I see in the chart (based on logic, intelligence, perception and reason predominantly) tells me that it will more than likely be filled.
The only slight doubt I have about it not being filled is because the 200MA line is now acting as support when approached from above, so a wave of buying is likely to happen if/when it hits it. The shorts will have to slam the bid hard if they want it to breach that level and that costs money. But considering that the FDA are likely to approve the label in some form, it is probably cost effective for them to do it, and then buy in the 16's and 17's because they know there's a very high probability the share price will be north of $30 soon enough. It's all a game.
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