Annual report pursuant to Section 13 and 15(d)

Document and Entity Information

Document and Entity Information - USD ($)
$ in Millions
12 Months Ended
Mar. 31, 2021
May 14, 2021
Sep. 30, 2020
Entity Central Index Key 0001002135    
Current Fiscal Year End Date --03-31    
Document Fiscal Year Focus 2021    
Document Fiscal Period Focus FY    
Amendment Flag false    
Entity Public Float     $ 14
Entity Address, State or Province IL    
Local Phone Number 898-2500    
City Area Code 630    
Entity Address, Postal Zip Code 60504    
Entity Address, City or Town Aurora    
Entity Address, Address Line One 750 North Commons Drive    
Entity Incorporation, State or Country Code DE    
Entity File Number 0-27266    
Entity Interactive Data Current Yes    
Document Quarterly Report true    
Document Transition Report false    
Entity Tax Identification Number 36-3154957    
ICFR Auditor Attestation Flag false    
Entity Current Reporting Status Yes    
Document Type 10-K    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Filer Category Non-accelerated Filer    
Entity Small Business true    
Entity Emerging Growth Company false    
Entity Shell Company false    
Entity Registrant Name WESTELL TECHNOLOGIES, INC.    
Document Period End Date Mar. 31, 2021    
Class A Common Stock [Member]      
Entity Common Stock, Shares Outstanding   7,635,998  
Class B Common Stock [Member]      
Entity Common Stock, Shares Outstanding   3,484,287