v3.26.1
Cover - USD ($)
$ in Millions
 12 Months Ended
Apr. 30, 2026
Aug. 18, 2026
Oct. 31, 2024
Document Type 10-K    
Amendment Flag false    
Document Annual Report true    
Document Transition Report false    
Document Period End Date Apr. 30, 2026    
Document Fiscal Period Focus FY    
Document Fiscal Year Focus 2026    
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   270,138,823  
ICFR Auditor Attestation Flag false    
Document Financial Statement Error Correction [Flag] true    
Document Financial Statement Restatement Recovery Analysis [Flag] false    
Auditor Firm ID 23    
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, 2026 and 2025, the related consolidated statements of operations, shareholders’ equity and cash flows for the years 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, 2026 and 2025, and the consolidated results of its operations and its cash flows for the years then ended, in conformity with accounting principles generally accepted in the United States of America.    
Auditor Name Baker Tilly US, LLP    
Auditor Location Dallas, Texas    
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