Inventories

The components of inventories consist of the following (in thousands):



	December 31, 2012		June 30, 2013
Purchased parts and materials	$	3,051	$	2,139
Finished goods	1,986		2,054
Total inventory	$	5,037	$	4,193

Inventories are valued at the lower of cost (first-in, first-out method) or market value. The valuation of production inventory requires us to estimate excess or obsolete inventory. The determination of excess or obsolete inventory requires us to estimate the future demand for our products. Our markets are volatile, subject to technological risks and price changes and inventory reduction programs by our customers. In addition, we are required to make last time buys of certain components on occasion. These factors result in a risk that we will forecast incorrectly and purchase excess inventories of particular products or have commitments to purchase excess inventory components from our suppliers. As a result, actual demand will differ from forecasts, and such a difference has in the past and may in the future have a material effect on our financial statements. Any write downs to inventory due to the existence of excess quantities, physical obsolescence, changes in pricing, damage, or other causes establish a new cost basis for the inventory. When we sell or dispose of reserved inventory the new cost basis is charged to cost of sales. Service inventory is amortized ratably over the estimated life of the related product series.