Balance Sheet Components - Schedule of Carrying Value of Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Mar. 31, 2023
Finite-Lived Intangible Assets [Line Items]
Gross	$ 5,224		$ 5,224		$ 5,224
Accumulated Amortization	(4,951)		(4,951)		(4,729)
Foreign Exchange Rate Changes	(174)		(174)		(174)
Net	99		99		321
Amortization expense	100	$ 100	200	$ 200
Patents
Finite-Lived Intangible Assets [Line Items]
Gross	2,963		2,963		2,963
Accumulated Amortization	(2,864)		(2,864)		(2,642)
Foreign Exchange Rate Changes	0		0		0
Net	$ 99		$ 99		$ 321
Estimated Useful Life (in years)	10 years		10 years		10 years
Developed Technology - 150 V
Finite-Lived Intangible Assets [Line Items]
Gross	$ 560		$ 560		$ 560
Accumulated Amortization	(517)		(517)		(517)
Foreign Exchange Rate Changes	(43)		(43)		(43)
Net	$ 0		$ 0		$ 0
Estimated Useful Life (in years)	6 years		6 years		6 years
Developed Technology - 600 V
Finite-Lived Intangible Assets [Line Items]
Gross	$ 1,701		$ 1,701		$ 1,701
Accumulated Amortization	(1,570)		(1,570)		(1,570)
Foreign Exchange Rate Changes	(131)		(131)		(131)
Net	$ 0		$ 0		$ 0
Estimated Useful Life (in years)	6 years		6 years		6 years