Qiagen is a spin-off of the University of Düsseldorf. I have lived in the Düsseldorf area for most of my life and while Qiagen is the only major company in a little town right next to Düsseldorf I think it is fair to say that almost no one in that town that is not working for them knows what they are doing. It is not really a secret, people just don't care. Excluding Genentech (Roche) and Serono (Merck) it might be the second largest (by market capitalisation, behind Actelion) "biotech company" in Europe. I think Qiagen has a decent chance of being a DAX30 component company in the not so distant future (see comment #9 here).
Qiagen shares are currently my third largest position (see comments #31,32 here).