Intangible assets

6 Months Ended

Sep. 30, 2021

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible assets

Intangible assets

Intangible assets comprise the following (in thousands):

		As of March 31, 2021						As of September 30, 2021
	Useful life (in years)	Gross Carrying amount		Accumulated amortization		Net		Gross Carrying amount		Accumulated amortization		Net
Patents and trademarks	3 - 20	$	115	$	(82)	$	33	$	113	$	(84)	$	29
Customer relationships	2 - 15	2,687		(2,271)		416		2,653		(2,330)		323
Internal-use software, technology and other	1 - 18	35,618		(17,764)		17,854		37,834		(19,337)		18,497
Total		$	38,420	$	(20,117)	$	18,303	$	40,600	$	(21,751)	$	18,849

For the three months ended September 30, 2020 and 2021, amortization expense of $0.9 million, and $1.0 million, respectively, has been recognized. For the six months ended September 30, 2020 and 2021, amortization expense of $1.7 million, and $2.0 million, respectively, has been recognized.