The most recent short interest precedes the recent pop. My guess is if we continue to rise we will start to see more heavy shorting, thus slowing the rise down. The only thing that might knock the upward slowdown off track is uncommitted shorts that shorted at a level that is starting to infringe on their sphincter.

http://www.nasdaq.com/symbol/mnkd/short-interest#.UT5PEzfzLFw

Swing