Current laboratory experiments indicate that direct dust growth via mutual collisions can only produce particles up to roughly mm to cm in size. On the other hand, it has been suggested that it is significantly more difficult for mm‐sized particles to spontaneously concentrate themselves in protoplanetary disks via the streaming instability to trigger planetesimal formation, in comparison to meter‐sized boulders. I will argue that previous models were under-resolved and significantly longer simulation time is needed. I will show that it is possible for particles of dimensionless stopping time 10^‐3 to concentrate themselves via the streaming instability at a solid abundance of a few percent. The solid density in the local concentrated regions can achieve as high as that on the order of the Roche density, which indicates possible direct gravitational collapse into planetesimals. These results bridge the gap of particle size in between direct dust growth and the streaming instability, and may have important consequences on dust coagulation and planetesimal formation models inside the ice line.