Cover Page - USD ($) $ in Billions	12 Months Ended
Cover Page - USD ($) $ in Billions	Mar. 31, 2026	May 11, 2026	Sep. 26, 2025
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Current Fiscal Year End Date	--03-31
Document Period End Date	Mar. 31, 2026
Document Transition Report	false
Entity File Number	001-41617
Entity Registrant Name	Nextpower Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	36-5047383
Entity Address, Address Line One	6200 Paseo Padre Parkway
Entity Address, City or Town	Fremont
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94555
City Area Code	510
Local Phone Number	270-2500
Title of 12(b) Security	Class A Common Stock, $0.0001 par value
Trading Symbol	NXT
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 10.8
Documents Incorporated by Reference	Portions of the registrant’s definitive Proxy Statement relating to its 2026 Annual Meeting of Stockholders are incorporated by reference into Part III of this Annual Report on Form 10-K where indicated. Such Proxy Statement will be filed with the United States Securities and Exchange Commission within 120 days after the end of the fiscal year to which this Annual Report on Form 10-K relates.
Entity Central Index Key	0001852131
Document Fiscal Year Focus	2026
Document Fiscal Period Focus	FY
Amendment Flag	false
Class A common stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		150,274,472
Class B common stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		0