Single-photon detectors are an integral part of experiments in quantum optics, and have applications in optical quantum computing, quantum communications, the characterization of single-photon sources, and free-space optical communications. In particular, superconducting nanowire single-photon detectors (SNSPDs) are excellent detectors in the near-infrared due to their fast recovery times, low jitter, and low dark count rates. Until recently however, the efficiency of SNSPDs in the telecommunications band was relatively poor in comparison to other detector technologies. I will discuss how the use of an amorphous superconductor, WSi, has led to significant improvement in system detection efficiency (~90%) compared to the early NbN-based SNSPDs. Furthermore, device yield has improved from ~30% with NbN to ~100% with WSi-based SNSPDs, enabling for the first time the fabrication of large (64 pixel) SNSPD arrays. I will outline the development of these SNSPD arrays, in addition to discussing novel device geometries and other amorphous superconductors such as MoSi, which are enabling operation of these detectors at higher temperatures.