XML 12 R1.htm IDEA: XBRL DOCUMENT v3.21.2
Cover - shares
 6 Months Ended
Oct. 31, 2021
Dec. 14, 2021
Cover [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Quarterly Report true  
Document Transition Report false  
Document Period End Date Oct. 31, 2021  
Document Fiscal Period Focus Q2  
Document Fiscal Year Focus 2022  
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  
Title of 12(b) Security Common Stock $0.001 par value  
Trading Symbol OPTT  
Security Exchange Name NYSE  
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 Common Stock, Shares Outstanding   55,873,173