4. Supplemental Balance Sheet Information

Inventories

Inventories are stated at the lower of cost or market value on a first-in, first-out basis and are comprised of the following (in thousands):

	March 31,		December 31,
	2015		2014
Raw materials	$	111	$	71
Work-in-process	141		44
Total inventories	$	252	$	115

Property and Equipment

Property and equipment consists of the following (in thousands):

	March 31, 2015			December 31, 2014
Office and computer equipment	$	384		$	383
Software	505			480
Laboratory equipment	3,380			3,312
Furniture	187			187
Manufacturing tooling and molds	26			26
Leasehold improvements	833			764
Construction in progress	2,428			387
T2Dx instruments and components	1,184			563
	8,927			6,102
Less accumulated depreciation and amortization	(3,595		)	(3,342		)
Property and equipment, net	$	5,332		$	2,760

Construction in progress is primarily comprised of equipment and leasehold improvement construction projects that have not been placed in service. T2Dx instruments and components is comprised of raw materials and work-in-process inventory that are expected to be used or used to produce Company-owned instruments, based on our business model and forecast, and completed instruments that will be used for internal research and development or reagent rental agreements with customers. Such completed instruments have not yet been placed in service.

Accrued Expenses

Accrued expenses consist of the following (in thousands):

	March 31,		December 31,
	2015		2014
Accrued payroll and compensation	$	1,457	$	1,846
Accrued professional services	428		374
Accrued research and development expenses	635		733
Other accrued expenses	906		709
Total accrued expenses	$	3,426	$	3,662