I'm no expert but......
My opinion is that the stock has been overbought yesterday/today. No recent changes or news to support anything other than the fact that warrants still outstanding and could be exercised soon.
First 5 min of trading today saw 1mil shares traded yet couldn't push through 0.51. Late morning another tap on 0.51ish but no break even though steady volume.
Taking a step back and looking at daily candles a pivot sign has formed today. On that same chart 20MA is resistance (at 0.51) and support is the 50MA down around 0.38-39.
With no change in news or situation at NPH the stock has been pumped up past couple days which would coincide with maximizing the potential value of exercising warrants soon (didn't this exact scenario happen last time warrants were exercised?). Perhaps an agreement with a firm to assist in this maneuver, buy it up, and simply signal them just before you exercise your warrants.
So what does this meean? Nothing has changed, the long term play is the same. But for those playing dips or waiting/missed the chance to get in. I suspect we will go back down to that 50MA on the daily chart (0.38-39) sometime in the next week. The hourly candles also support this showing overbough.