Mac OS X cannot passthrough USB device to guest

I'm using Mac OS 10.9.4 with qemu-system-arm installed from brew (version 1.7.1) and verified with qemu-system-x86_64. I'm trying to pass a Ralink 5370 WiFi USB dongle to my guest system, it appears in my system profiler as:

802.11 n WLAN:

  Product ID:	0x5370
  Vendor ID:	0x148f
  Version:	 1.01
  Serial Number:	1.0
  Speed:	Up to 480 Mb/sec
  Manufacturer:	Ralink
  Location ID:	0x1d110000 / 6
  Current Available (mA):	500
  Current Required (mA):	450

Using the docs, I'm passing "-usb -device usb-host,vendorid=0x148f,productid=0x5370" and getting this error back:
"qemu-system-arm: -device usb-host,vendorid=0x148f,productid=0x5370: Parameter 'driver' expects device type"