v3.25.2
Cover
12 Months Ended
Mar. 31, 2025
shares
Document Information [Line Items]  
Document Type 20-F
Document Registration Statement false
Document Annual Report true
Document Transition Report false
Document Financial Statement Error Correction [Flag] false
Document Shell Company Report false
Entity Interactive Data Current Yes
Document Accounting Standard U.S. GAAP
ICFR Auditor Attestation Flag false
Amendment Flag false
Document Period End Date Mar. 31, 2025
Document Fiscal Year Focus 2025
Document Fiscal Period Focus FY
Entity Information [Line Items]  
Entity Registrant Name DESWELL INDUSTRIES, INC.
Entity Central Index Key 0000946936
Entity File Number 001-33900
Entity Incorporation, State or Country Code D8
Current Fiscal Year End Date --03-31
Entity Well-known Seasoned Issuer No
Entity Voluntary Filers No
Entity Current Reporting Status Yes
Entity Shell Company false
Entity Filer Category Non-accelerated Filer
Entity Emerging Growth Company false
Entity Incorporation, Date of Incorporation Dec. 02, 1993
Entity Contact Personnel [Line Items]  
Entity Address, Address Line One 10B, Edificio Associacao Industrial De Macau
Entity Address, Address Line Two 32 Rua do Comandante Mata e Oliveria
Entity Address, City or Town Macao
Entity Address, Country CN
Entity Address, Postal Zip Code 0000
Entity Listings [Line Items]  
Title of 12(b) Security Common shares, no par value
Trading Symbol DSWL
Security Exchange Name NASDAQ
Entity Common Stock, Shares Outstanding 15,935,239
Business Contact [Member]  
Entity Contact Personnel [Line Items]  
Contact Personnel Name Herman Wong
Contact Personnel Email Address hermanwong@jetcrown.net
Contact Personnel Fax Number 853-28-323265
Entity Address, Address Line One 10B, Edificio Associacao Industrial De macau
Entity Address, Address Line Two 32 Rua do Comandante Mata e Oliveira
Entity Address, City or Town Macao
Entity Address, Country CN
Entity Address, Postal Zip Code 0000
Entity Phone Fax Numbers [Line Items]  
City Area Code 853
Local Phone Number -28-322096