XML 41 R28.htm IDEA: XBRL DOCUMENT
v3.22.2

Summary of Significant Accounting Policies (Tables) | 12 Months Ended
--- | ---
Apr. 30, 2022
Accounting Policies [Abstract] |
Schedule of Cash and Cash Equivalents | Schedule of Cash and Cash Equivalents
|  | April 30, 2022 |  |  | April 30, 2021 |
|  | (in thousands) |
Checking and savings accounts |  | $ | 1,815 |  |  | $ | 1,850 |
Money market account |  |  | 6,070 |  |  |  | 81,178 |
|  | $ | 7,885 |  |  | $ | 83,028 |
Schedule of Cash and Cash Equivalents and Restricted Cash | The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the Consolidated Balance Sheets that total to the same amounts shown in the Consolidated Statements of Cash Flows. Schedule of Cash and Cash Equivalents and Restricted Cash
|  | April 30, 2022 |  |  | April 30, 2021 |
|  | (in thousands) |
Cash and cash equivalents |  | $ | 7,885 |  |  | $ | 83,028 |
Restricted cash- short term |  |  | 258 |  |  |  | 384 |
Restricted cash- long term |  |  | 219 |  |  |  | 222 |
Cash, cash equivalents, restricted cash and restricted cash equivalents |  | $ | 8,362 |  |  | $ | 83,634 |
Schedule of Investments and Unrealized Gains/Losses | The following table represents the fair value of the investments and unrealized gains/losses by class, which have been recorded at amortized costs as of April 30, 2022: Schedule of Investments and Unrealized Gains/Losses
Category |  | Cost or Amortized Cost |  |  | Gross Unrealized Gains |  |  | Gross Unrealized Losses |  |  | Estimated Fair Value |  |  | Net Unrealized Gains/(Losses) |
Held-to-Maturity Securities |  | $ | 49,384 |  |  | $ | 81 |  |  | $ | (414 | ) |  | $ | 49,051 |  |  | $ | (333 | )
Schedule of Property, Plant and Equipment, Useful Life | Schedule of Property, Plant and Equipment, Useful Life
Description |  | Estimated useful life
Equipment |  | 5-7 years
Computer equipment & software |  | 3 years
Office furniture & fixtures |  | 3-7 years
Equipment under capitalized lease |  | Over the life of the lease
Leasehold improvements |  | Shorter of the estimated useful life or lease term
Schedule of Revenue by Major Customers by Reporting Segments | The table below shows the percentage of the Company’s revenues derived from customers whose revenues accounted for at least 10% of the Company’s consolidated revenues for at least one of the periods indicated: Schedule of Revenue by Major Customers by Reporting Segments
Customer |  | 2022 |  |  | 2021 |
|  | Twelve months ended April 30, |
Customer |  | 2022 |  |  | 2021 |
Transocean Ltd. |  |  | 15 | % |  |  | — | %
Valaris PLC |  |  | 12 | % |  |  | — | %
Diamond Offshore Drilling, Inc. |  |  | 11 | % |  |  | — | %
United States Department of Energy |  |  | 11 | % |  |  | — | %
Enel Green Power Chile, LTDA |  |  | 9 | % |  |  | 61 | %
Eni S.p.A. |  |  | 1 | % |  |  | 22 | %
Other (no other customers over 10%) |  |  | 41 | % |  |  | 17 | %
Revenues, percentage |  |  | 100 | % |  |  | 100 | %

X
- Definition Property Plant And Equipment Useful Life [Table Text Block] + References No definition available. + Details
Name: | OPTT_PropertyPlantAndEquipmentUsefulLifeTableTextBlock
Namespace Prefix: | OPTT_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_AccountingPoliciesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the components of cash and cash equivalents. + References No definition available. + Details
Name: | us-gaap_ScheduleOfCashAndCashEquivalentsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of cash and cash equivalents restricted as to withdrawal or usage. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(1)(a)) -URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 8 -URI https://asc.fasb.org/extlink&oid=126999549&loc=SL98516268-108586 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(2)) -URI https://asc.fasb.org/extlink&oid=126734703&loc=d3e572229-122910 + Details
Name: | us-gaap_ScheduleOfRestrictedCashAndCashEquivalentsTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the extent of the entity's reliance on its major customers, if revenues from transactions with a single external customer amount to 10 percent or more of entity revenues, including the disclosure of that fact, the total amount of revenues from each such customer, and the identity of the reportable segment or segments reporting the revenues. The entity need not disclose the identity of a major customer or the amount of revenues that each segment reports from that customer. For these purposes, a group of companies known to the entity to be under common control is considered a single customer, and the federal government, a state government, a local government such as a county or municipality, or a foreign government is each considered a single customer. + References No definition available. + Details
Name: | us-gaap_ScheduleOfRevenueByMajorCustomersByReportingSegmentsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of unrealized gains and losses on investments. + References No definition available. + Details
Name: | us-gaap_UnrealizedGainLossOnInvestmentsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration