  Submillimeter cameras now have up to $10^4$ pixels (SCUBA 2). The proposed
CCAT 25-meter submillimeter telescope will feature a 1 degree field-of-view.
Populating the focal plane at 350 microns would require more than $10^6$
photon-noise limited pixels. To ultimately achieve this scaling, simple
detectors and high-density multiplexing are essential. We are addressing this
long-term challenge through the development of frequency-multiplexed
superconducting microresonator detector arrays. These arrays use
lumped-element, direct-absorption resonators patterned from titanium nitride
films. We will discuss our progress toward constructing a scalable 350 micron
pathfinder instrument focusing on fabrication simplicity, multiplexing density,
and ultimately a low per-pixel cost.
