The following table presents changes in the carrying amount of goodwill for the years ended December 31, 2019, and 2018.



	Life Sciences			Mobile Solutions			Power Solutions			Total
Balance as of December 31, 2017	$	177,784		$	74,147		$	202,681		$	454,612
Currency impact and other	(3,118		)	(705		)	(1,882		)	(5,705		)
Goodwill acquired in acquisitions	165,288			—			2,657			167,945
Impairments	—			(73,442		)	(109,100		)	(182,542		)
Measurement period adjustments	4,993			—			149			5,142
Balance as of December 31, 2018	344,947			—			94,505			439,452
Currency impact and other	(631		)	—			274			(357		)
Balance as of December 31, 2019	$	344,316		$	—		$	94,779		$	439,095

The following table presents the gross carrying amount of goodwill and accumulated impairment charges as of December 31, 2019, and 2018.



	December 31, 2019							December 31, 2018
	Gross Carrying Amount		Accumulated Impairment Charges			Net Book Value		Gross Carrying Amount		Accumulated Impairment Charges			Net Book Value
Life Sciences	$	344,316	$	—		$	344,316	$	344,947	$	—		$	344,947
Mobile Solutions	77,458		(77,458		)	—		77,650		(77,650		)	—
Power Solutions	215,628		(120,849		)	94,779		215,354		(120,849		)	94,505
Total goodwill	$	637,402	$	(198,307	)	$	439,095	$	637,951	$	(198,499	)	$	439,452

We review goodwill for impairment on a reporting unit basis annually during the fourth quarter of each year, using a measurement date of October 1^st, and whenever events or changes in circumstances indicate the carrying value of goodwill may not be recoverable. Reporting units for the purpose of goodwill impairment testing are the same as our operating segments (Life Sciences, Mobile Solutions and Power Solutions). Based on the results of the quantitative measurement performed, which indicated a fair value in excess of carrying amount for each of our designated reporting units, we concluded there was no impairment of goodwill for the year ended December 31, 2019.

The fair value of the Power Solutions reporting unit exceeds the carrying value by approximately 5% as of the date of our annual impairment test. If our assessment of the relevant facts and circumstances changes, or the actual performance falls short of the expected results, impairment charges may be required.

During the fourth quarter of 2018, our market capitalization declined to a level that was less than the net book value of our stockholders’ equity. We performed our annual goodwill impairment analysis as of October 1, 2018, and elected to early adopt ASU 2017-4, Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment. As a result of our analysis, we recorded an impairment loss on goodwill in 2018 of $73.4 million and $109.1 million for Mobile Solutions and Power Solutions, respectively, to the “Goodwill impairment” line on the Consolidated Statements of Operations and Comprehensive Income (Loss). In addition, goodwill in Power Solutions was reduced by $1.6 million related to adjusting deferred tax liabilities for tax deductible goodwill, which is reflected in “Currency impact and other” in the above table. No goodwill impairment loss was recorded at Life Sciences in 2018.

Goodwill acquired in 2018 is related to the acquisitions as described in Note 4 and is derived from the value of the businesses acquired. During 2018, we recorded $161.8 million of goodwill related to the Paragon Medical acquisition, $8.0 million related to the Bridgemedica acquisition, and $2.8 million related to the Technical Arts acquisition. We finalized our valuations related to the 2018 acquisitions in 2019 with no material changes to the initial purchase price allocation.

As noted above, it was determined under a quantitative assessment that there was no impairment of goodwill in 2019. However, if we become aware of indicators of impairment in future periods, we may be required to perform an interim assessment for some or all of our reporting units before the next annual assessment. Examples of such indicators may include a decrease in expected net earnings, adverse equity market conditions, a decline in current market multiples, a decline in our common stock price, a significant adverse change in legal factors or business climates, an adverse action or assessment by a regulator, unanticipated competition, strategic decisions made in response to economic or competitive conditions, or a more likely than not expectation that a reporting unit or a significant portion of a reporting unit will be sold or disposed of. In the event of significant adverse changes of the nature described above, we may have to recognize a non-cash impairment of goodwill, which could have a material adverse effect on our consolidated financial condition and results of operations.

Based on the closing sales price of a share of our common stock as of December 31, 2019, our market capitalization exceeded the $353.3 million net book value of our stockholders’ equity. Subsequent to December 31, 2019, our market capitalization declined to a level that is less than the net book value of our stockholders’ equity. A prolonged or significant decline in market capitalization could be an indicator of possible goodwill impairment. We will continue to monitor the market capitalization relative to net book value in subsequent periods.