	Premises			Identity		Total
Balance as of December 31, 2019	$	6,684		$	3,554	$	10,238
Currency translation adjustment		(100	)		—		(100	)
Balance as of March 31, 2020	$	6,584		$	3,554	$	10,138

The Company tests goodwill for impairment on an annual basis, in the fourth quarter, or whenever events or changes in circumstances indicate that the carrying amount of these assets may not be recoverable. In testing for goodwill impairment, the Company compares the fair value of its reporting unit to its carrying value including the goodwill of that unit. If the carrying value, including goodwill, exceeds the reporting unit’s fair value, the Company will recognize an impairment loss for the amount by which the carrying amount exceeds the reporting unit’s fair value. During the quarter ended March 31, 2020, the Company noted no indicators of goodwill impairment and concluded no further testing was necessary.

The following table summarizes the gross carrying amount and accumulated amortization for intangible assets resulting from acquisitions (in thousands):

				Developed			Customer
	Trademarks			Technology			Relationships			Total
Amortization period (in years)	5			10 – 12			4 – 12

Gross carrying amount as of March 31, 2020	$	749		$	9,054		$	15,712		$	25,515
Accumulated amortization		(267	)		(5,098	)		(10,808	)		(16,173	)
Intangible assets, net as of March 31, 2020	$	482		$	3,956		$	4,904		$	9,342

Gross carrying amount as of December 31, 2019	$	763		$	9,109		$	15,763		$	25,635
Accumulated amortization		(229	)		(4,873	)		(10,429	)		(15,531	)
Intangible assets, net as of December 31, 2019	$	534		$	4,236		$	5,334		$	10,104

Each period, the Company evaluates the estimated remaining useful lives of purchased intangible assets and whether events or changes in circumstances warrant a revision to the remaining period of amortization. If a revision to the remaining period of amortization is warranted, amortization is prospectively adjusted over the remaining useful life of the intangible asset. Intangible assets subject to amortization are amortized on a straight-line basis over their useful lives as shown in the table above. The Company performs an evaluation of it its amortizable intangible assets for impairment at the end of each reporting period. The Company did not identify any impairment indicators during the three months ended March 31, 2020.

The following table illustrates the amortization expense included in the condensed consolidated statements of operations for the three months ended March 31, 2020 and 2019, respectively (in thousands):

	Three Months Ended
	March 31,
	2020		2019
Cost of revenue	$	224	$	224
Selling and marketing		418		418
Total	$	642	$	642

The estimated annual future amortization expense for purchased intangible assets with definite lives as of March 31, 2020 was as follows (in thousands):