Our data from 351 innovating firms for the years 2001–2012 generally suggest that patentable ideas are strongly linked to the mobility of individual inventors, or that the knowledge flows transmitted are sticky inventor-specific. In other words, the larger the knowledge pool of an inventor entering (leaving) the firm, the more the firm’s innovation performance increases (decreases). However, our separate estimations for six different technology classes suggest that this does not apply for all technologies. Our data indicate that the knowledge flows are mobile inventor-specific for chemicals and pharmaceuticals and mechanical engineering such that the mobility of an inventor to a firm increases its innovation performance but the mobility of an inventor from a firm does not affect its innovation performance. We further find that particularly innovation coopetition (i.e., collaboration with a firm’s competitors) is an important source of knowledge spillovers. Furthermore, the magnitude of overall localized innovation activity positively relates to the firm’s innovation performance providing support for agglomeration externalities.