Intangible Assets

3 Months Ended

Mar. 31, 2022

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible Assets

Note 5. Intangible Assets

The following table summarizes the gross book value, accumulated amortization and net book value balances of intangible assets as of March 31, 2022 and December 31, 2021 (in thousands):

	March 31, 2022						December 31, 2021
	Gross Book Value		Accumulated Amortization		Net Book Value		Gross Book Value		Accumulated Amortization		Net Book Value
Licensing Agreement(1)	$	29,400	$	20,266	$	9,134	$	29,400	$	19,780	$	9,620
Trade names and trademarks		210		55		155		210		50		160
Customer relationships		240		62		178		240		56		184
Total intangible assets	$	29,850	$	20,383	$	9,467	$	29,850	$	19,886	$	9,964

⁽¹⁾ Prior to the acquisition, Enteris entered into a non-exclusive commercial license agreement (the “License Agreement”) with Cara Therapeutics, Inc. (“Cara”), for oral formulation rights to Enteris’ Peptelligence® technology to develop and commercialize Oral KORSUVA^TM in any indication worldwide, excluding South Korea and Japan. Cara is obligated to pay Enteris certain development, regulatory and tiered commercial milestone payments, as well as low single-digit royalties based on net sales in the licensed territory.

Amortization expense related to intangible assets was $0.5 million and $1.6 million for the three months ended March 31, 2022 and 2021, respectively.

The estimated future amortization expense related to intangible assets as of March 31, 2022 is as follows (in thousands):

Fiscal Year	Amount
Remainder of 2022	$	1,277
2023		1,703
2024		1,546
2025		1,076
2026		1,076
Thereafter		2,789
Total	$	9,467