8. Goodwill

Goodwill represents the excess of the cost of an acquired entity over the fair value assigned to the assets purchased and liabilities assumed in connection with a business acquisition. Goodwill is not amortized but is subject, at a minimum, to annual tests for impairment in accordance with accounting guidance for goodwill. The carrying amount of goodwill is evaluated annually, and between annual evaluations if events occur or circumstances change indicating that the carrying amount of goodwill may be impaired.

Goodwill as of December 31, 2017 and September 30, 2017 totaled $27.5 million and $27.3 million, respectively. Goodwill in the Medical Device reporting unit represents the gross value from the fiscal 2016 acquisitions of Creagh Medical and NorMedix. Goodwill in the In Vitro Diagnostics reporting unit represents the gross value from the acquisition of BioFX Laboratories, Inc. (“BioFX”) in fiscal 2007.

Goodwill was not impaired in either reporting unit based on the outcome of the fiscal 2017 annual impairment test, and there have been no events or circumstances that have occurred in the first three months of fiscal 2018 to indicate that goodwill has been impaired.

The change in the carrying amount of goodwill by segment for the three months ended December 31, 2017 was as follows:

(Dollars in thousands)	In Vitro Diagnostics		Medical Device		Total
Balance as of September 30, 2017	$	8,010	$	19,272	$	27,282
Currency translation adjustment		—		223		223
Balance as of December 31, 2017	$	8,010	$	19,495	$	27,505