E. Inventories

Our major classes of inventories were as follows as of December 31, 2013 and 2012 (in thousands):

	December 31,

	2013		2012
Raw materials	$	3,157	$	2,652
Work in process		8,322		2,524
Finished goods		5,738		7,275


Total inventories	$	17,217	$	12,451

During 2013, we expensed $1.1 million of commercial inventory deemed no longer saleable, which we recorded in cost of goods sold. In addition, during 2013, we expensed $1.1 million of commercial inventory which we determined would solely be used in manufacturing processes development activities at our third-party suppliers, which we have recorded in research and development expense.

During 2012, we expensed $0.6 million of inventory which was initially produced to validate the manufacturing process at third-party suppliers and which we no longer believed was suitable for sale. We have recorded this $0.6 million in research and development expenses. In addition, during 2012, we expensed $0.6 million of commercial inventory deemed no longer saleable, which we recorded in cost of goods sold. We expensed $0.7 million of additional inventory related to our then-ongoing divestiture of our Cambridge, Massachusetts manufacturing facility and recorded the expense in restructuring costs.

On a quarterly basis, we analyze our inventory levels to determine whether we have any obsolete, expired, or excess inventory. If any inventory is expected to expire prior to being sold, has a cost basis in excess of its net realizable value, is in excess of expected sales requirements as determined by internal sales forecasts, or fails to meet commercial sale specifications, the inventory is written-down through a charge to cost of goods sold. The determination of whether inventory costs will be realizable requires estimates by management of future expected inventory requirements, based on internal sales forecasts and forecasts received from Takeda. Once packaged, Feraheme/Rienso currently has a shelf-life of five years in the U.S. and between two and three years outside of the U.S., and as a result of comparison to internal sales forecasts, we expect to fully realize the carrying value of our current Feraheme/Rienso finished goods inventory. If actual market conditions are less favorable than those projected by management, additional inventory write-downs may be required. Charges for inventory write-downs are not reversed if it is later determined that the product is saleable.