Based on theories of inter-organizational knowledge flows and organizational learning, we argue that intensively accessing knowledge from a limited number of external channels, i.e., open search depth, can facilitate the innovating company's incremental innovation performance. We also argue that accessing knowledge from a broad range of external channels, i.e., open search breadth, can enhance the innovating firm's radical innovation performance. Using hierarchical regressions to analyze survey data collected from 184 Taiwanese electronic product manufacturers, we found that open search depth is positively related to the innovating firm's incremental innovation performance, and that open search breadth is positively related to radical innovation performance. As our results differ from those of previous studies, we provide a possible explanation for the discrepancy. Examining the effect of open search strategy from a theoretical angle not yet explored before, our findings can contribute to both scholarly and practitioner knowledge of open innovation.