	Identity		Premises		Total
Balance as of December 31, 2020	$	3,554	$	6,712	$	10,266
Currency translation adjustment		—		15		15
Balance as of March 31, 2021	$	3,554	$	6,727	$	10,281

Balance as of December 31, 2021	$	3,554	$	6,714	$	10,268
Currency translation adjustment		—		20		20
Balance as of March 31, 2022	$	3,554	$	6,734	$	10,288

In accordance with ASC 350, Intangibles – Goodwill and Other, 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. The Company performs an initial assessment of qualitative factors to determine whether the existence of events and circumstances leads to a determination that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. In performing the qualitative assessment, the Company identifies and considers the significance of relevant key factors, events, and circumstances that affect the fair value of its reporting units. These factors include external factors such as macroeconomic, industry, and market conditions, as well as entity-specific factors, such as actual and planned financial performance. If, after assessing the totality of relevant events and circumstances, the Company determines that it is more likely than not that the fair value of the reporting unit exceeds its carrying value and there is no indication of impairment, no further testing is performed; however, if the Company concludes otherwise, then the Company will perform the quantitative impairment test which compares the estimated fair value of the reporting unit to its carrying value, including goodwill. If the carrying amount of the reporting unit is in excess of its fair value, an impairment loss would be recorded in the condensed consolidated statement of comprehensive loss. During the three months ended March 31, 2022 and 2021, 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, 2022	$	767		$	9,136		$	15,779		$	25,682
Accumulated amortization		(575	)		(6,331	)		(12,594	)		(19,500	)
Intangible assets, net as of March 31, 2022	$	192		$	2,805		$	3,185		$	6,182

Gross carrying amount as of December 31, 2021	$	764		$	9,127		$	15,774		$	25,665
Accumulated amortization		(536	)		(6,219	)		(12,465	)		(19,220	)
Intangible assets, net as of December 31, 2021	$	228		$	2,908		$	3,309		$	6,445

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 indicated in the table above. The Company performs an evaluation of 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, 2022 and 2021.

The following table summarizes the amortization expense included in the condensed consolidated statements of comprehensive loss for the three months ended March 31, 2022 and 2021, respectively (in thousands):

	Three Months Ended March 31,
	2022		2021
Cost of revenue	$	112	$	119
Selling and marketing		168		160
Total	$	280	$	279

The estimated annual future amortization expense for purchased intangible assets with definite lives as of March 31, 2022 was as follows (in thousands):