v3.25.2
Cover - USD ($)
$ in Millions
 12 Months Ended
Apr. 30, 2025
Apr. 30, 2024
Jul. 22, 2025
Oct. 31, 2024
Document Type 10-K      
Amendment Flag false      
Document Annual Report true      
Document Transition Report false      
Document Period End Date Apr. 30, 2025      
Document Fiscal Period Focus FY      
Document Fiscal Year Focus 2025      
Current Fiscal Year End Date --04-30      
Entity File Number 001-33417      
Entity Registrant Name Ocean Power Technologies, Inc.      
Entity Central Index Key 0001378140      
Entity Tax Identification Number 22-2535818      
Entity Incorporation, State or Country Code DE      
Entity Address, Address Line One 28 ENGELHARD DRIVE      
Entity Address, Address Line Two SUITE B      
Entity Address, City or Town MONROE TOWNSHIP      
Entity Address, State or Province NJ      
Entity Address, Postal Zip Code 08831      
City Area Code (609)      
Local Phone Number 730-0400      
Entity Well-known Seasoned Issuer No      
Entity Voluntary Filers No      
Entity Current Reporting Status Yes      
Entity Interactive Data Current Yes      
Entity Filer Category Non-accelerated Filer      
Entity Small Business true      
Entity Emerging Growth Company false      
Entity Shell Company false      
Entity Public Float       $ 18.7
Entity Common Stock, Shares Outstanding     177,542,775  
ICFR Auditor Attestation Flag false      
Document Financial Statement Error Correction [Flag] false      
Auditor Firm ID 23 274    
Auditor Opinion [Text Block] We have audited the accompanying consolidated balance sheet of Ocean Power Technologies, Inc. (and subsidiaries) (the “Company”) as of April 30, 2025, the related consolidated statements of operations, shareholders’ equity and cash flows for the year then ended, and the related notes (collectively referred to as the “consolidated financial statements”). In our opinion, the consolidated financial statements present fairly, in all material respects, the consolidated financial position of the Company as of April 30, 2025, and the consolidated results of its operations and its cash flows for the year then ended, in conformity with accounting principles generally accepted in the United States of America.      
Auditor Name Baker Tilly US, LLP EISNERAMPER LLP    
Auditor Location Dallas, Texas Iselin, NJ    
Common Stock, par value $0.001 [Member]        
Title of 12(b) Security Common Stock, par value $0.001      
Trading Symbol OPTT      
Security Exchange Name NYSEAMER      
Series A Preferred Stock Purchase Rights [Member]        
Title of 12(b) Security Series A Preferred Stock Purchase Rights      
No Trading Symbol Flag true      
Security Exchange Name NYSEAMER