0001493152-22-019173 | 10-K | XBRL Viewer | Ocean Power Technologies INC

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Cover - USD ($) $ in Millions	12 Months Ended
Cover - USD ($) $ in Millions	Apr. 30, 2022	Jul. 13, 2022	Oct. 31, 2021
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Apr. 30, 2022
Document Fiscal Period Focus	FY
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, par value $0.001
Trading Symbol	OPTT
Security Exchange Name	NYSE
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			$ 40.8
Entity Common Stock, Shares Outstanding		55,881,861
ICFR Auditor Attestation Flag	true
Auditor Firm ID	274
Auditor Name	EisnerAmper LLP
Auditor Location	Iselin, New Jersey

Consolidated Balance Sheets - USD ($) $ in Thousands	Apr. 30, 2022	Apr. 30, 2021
Current assets:
Cash and cash equivalents	$ 7,885	$ 83,028
Short-term investments	49,384
Restricted cash, short-term	258	384
Accounts receivable	482	350
Contract assets	386	190
Inventory	442
Other current assets	467	487
Total current assets	59,304	84,439
Property and equipment, net	445	406
Intangibles, net	4,136	274
Right-of-use asset, net	752	1,036
Restricted cash, long-term	219	222
Goodwill	8,537
Total assets	73,393	86,377
Current liabilities:
Accounts payable	905	687
Accrued expenses	877	1,881
Contract liabilities	129
Right-of-use liability, current portion	319	347
Contingent liabilities, current portion	748
Litigation payable		1,224
Liability classified stock awards		60
Paycheck protection program loan, current portion		495
Total current liabilities	2,978	4,694
Deferred tax liability	203
Contingent liabilities, less current portion	843
Paycheck protection program loan, less current portion		396
Right-of-use liability, less current portion	538	819
Total liabilities	4,562	5,909
Commitments and contingencies (Note 17)
Shareholders’ Equity:
Preferred stock, $0.001 par value; authorized 5,000,000 shares, none issued or outstanding
Common stock, $0.001 par value; authorized 100,000,000 shares, issued and outstanding 55,905,213 and 52,479,051 shares, respectively	56	52
Treasury stock, at cost; 23,352 and 21,040 shares, respectively	(341)	(338)
Additional paid-in capital	322,932	315,820
Accumulated deficit	(253,770)	(234,895)
Accumulated other comprehensive loss	(46)	(171)
Total shareholders’ equity	68,831	80,468
Total liabilities and shareholders’ equity	$ 73,393	$ 86,377

Consolidated Balance Sheets (Parenthetical) - $ / shares	Apr. 30, 2022	Apr. 30, 2021
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	55,905,213	52,479,051
Common stock, shares outstanding	55,905,213	52,479,051
Treasury stock, shares	23,352	21,040

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Apr. 30, 2022	Apr. 30, 2021
Income Statement [Abstract]
Revenues	$ 1,759	$ 1,206
Cost of revenues	1,860	2,279
Gross loss	(101)	(1,073)
Operating expenses	21,512	12,519
Operating loss	(21,613)	(13,592)
Litigation settlement		(1,224)
Interest income, net	124	124
Other income	60
Gain on forgiveness of PPP loan	890
Loss on liquidation of subsidiary	(157)
Other expense, net		(83)
Foreign exchange (loss) / gain	(1)	15
Loss before income taxes	(20,697)	(14,760)
Income tax benefit	1,823
Net loss	$ (18,874)	$ (14,760)
Basic and diluted net loss per share	$ (0.35)	$ (0.49)
Weighted average shares used to compute basic and diluted net loss per share	54,010,233	30,018,838

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2022	Apr. 30, 2021
Income Statement [Abstract]
Net loss	$ (18,874)	$ (14,760)
Foreign currency translation adjustment	(32)	12
Total comprehensive loss	$ (18,906)	$ (14,748)

- Definition

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income. Excludes changes in equity resulting from investments by owners and distributions to owners.

+ References + Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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+ Details

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Beginning balance, value at Apr. 30, 2020	$ 13	$ (302)	$ 231,101	$ (220,136)	$ (183)	$ 10,493
Balance, shares at Apr. 30, 2020	12,939,420	(4,251)
Net loss				(14,760)		(14,760)
Share-based compensation			721			721
Issuance (forfeiture) of restricted stock, net			184			184
Issuance (forfeiture) of restricted stock, net, shares	175,500
Exercise of prefunded warrants, net of costs	$ 1		2,818			2,819
Exercise of common warrants, net of costs, shares	732,500
Issuance of common stock- Aspire financing, net of issuance costs	$ 8		14,384			14,392
Issuance of common stock- Aspire financing, net of issuance costs, shares	8,747,251
Issuance of common stock- AGP At The Market offering, net of issuance costs	$ 30		66,136			66,166
Issuance of common stock- AGP At The Market offering, net of issuance costs, shares	29,522,389
Issuance of shares in acquisition			477			477
Issuance of shares in acquisition, shares	361,991
Acquisition of treasury stock		$ (36)				$ (36)
Acquisition of treasury stock, shares		(16,789)				16,789
Other comprehensive loss					12	$ 12
Ending balance, value at Apr. 30, 2021	$ 52	$ (338)	315,821	(234,896)	(171)	80,468
Balance, shares at Apr. 30, 2021	52,479,051	(21,040)
Net loss				(18,874)		(18,874)
Share-based compensation			1,169			1,169
Issuance of shares in acquisition	$ 3		5,852			5,855
Issuance of shares in acquisition, shares	3,330,162
Acquisition of treasury stock		$ (3)				$ (3)
Acquisition of treasury stock, shares		(2,312)				2,312
Other comprehensive loss					(32)	$ (32)
Proceeds from stock options exercises	$ 1		90			$ 91
Proceeds from stock options exercises, shares	96,000					45,332
Liquidation of subsidiary					157	$ 157
Ending balance, value at Apr. 30, 2022	$ 56	$ (341)	$ 322,932	$ (253,770)	$ (46)	$ 68,831
Balance, shares at Apr. 30, 2022	55,905,213	(23,352)

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2022	Apr. 30, 2021
Cash flows from operating activities:
Net loss	$ (18,874)	$ (14,760)
Adjustments to reconcile net loss to net cash used in operating activities:
Foreign exchange (gain) / loss	1	(15)
Depreciation of fixed assets	144	143
Amortization of intangibles	86	6
Amortization of right of use asset	285	223
Amortization of premium on investments	58
Gain on forgiveness of PPP loan	(890)
Loss on liquidation of subsidiary	157
Compensation expense related to equity compensation	1,169	721
Deferred tax liabilities	(377)
Performance obligation shares compensation	(60)	60
Net effect from disposal of property, plant and equipment		2
Accounts receivable	(133)	(245)
Contract assets	(195)	61
Inventory	(292)
Other assets	19	106
Accounts payable	217	441
Accrued expenses	(1,004)	761
Litigation payable	(1,224)	1,224
Change in right of use lease liability	(309)	(237)
Contract liabilities	(74)	(165)
Net cash used in operating activities	(21,296)	(11,674)
Cash flows from investing activities:
Cash acquired in acquisition		100
Purchase of short-term investments	(49,442)
Purchase of property, plant and equipment	(145)	(26)
Payment for MAR acquisition, net of cash acquired	(4,444)
Net cash (used in) provided by investing activities	(54,031)	74
Cash flows from financing activities:
Proceeds from Paycheck Protection Program Loan		890
Proceeds from loan payable		467
Payment of loan payable		(467)
Proceeds from stock option exercises	90	184
Payment of payroll taxes related to stock option exercises		(245)
Proceeds from issuance of common stock- Aspire financing net of issuance costs		14,393
Proceeds from issuance of common stock- AGP At The Market offering, net of issuance costs		66,166
Proceeds associated with exercise of common stock warrants		2,818
Acquisition of treasury stock	(3)	(36)
Net cash provided by financing activities	87	84,170
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(32)	134
Net (decrease) / increase in cash, cash equivalents and restricted cash	(75,272)	72,704
Cash, cash equivalents and restricted cash, beginning of year	83,634	10,930
Cash, cash equivalents and restricted cash, end of year	8,362	83,634
Supplemental disclosure of noncash investing and financing activities:
Acquisition of property, plant and equipment through accounts payable		6
Issuance of stock for acquisition	5,855	477
Contingent liability - MAR	$ 1,591

Background and Liquidity

12 Months Ended

Apr. 30, 2022

Accounting Policies [Abstract]

Background and Liquidity

(1) Background and Liquidity

(a) Background

Ocean Power Technologies, Inc. (the “Company”) was founded in 1984 in New Jersey, commenced business operations in 1994 and re-incorporated in Delaware in 2007. We are a complete solutions provider, controlling the design, manufacturing, sales, installation, operations and maintenance of our products and services. Our solutions provide distributed offshore power which is persistent, reliable, and economical along with power and communications for remote surface and subsea applications. Historically, funding from government agencies, such as research and development grants, accounted for a significant portion of the Company’s revenues. Today our goal is to generate the majority of our revenues from the sale or lease of our products and solutions, and sales of services to support our business operations. As we continue to develop and commercialize our products and services, we expect to have a net decrease in cash due to the use of cash from operating activities unless and until we achieve positive cash flow from the commercialization of products, solutions and services.

(b) Liquidity

For Fiscal 2022

For the fiscal year ended April 30, 2022, and the fiscal year ended April 30, 2021, the Company incurred net losses of approximately $18.9 million and $14.8 million, respectively, and used cash in operating activities of approximately $21.4 million and $11.7 million, respectively. The Company has continued to make investments in ongoing product development efforts in anticipation of future growth, including its recent acquisition of Marine Advanced Robotics, Inc., as described in Note 18. The Company’s future results of operations involve significant risks and uncertainties. Factors that could affect the Company’s future operating results and could cause actual results to vary materially from expectations include, but are not limited to, performance of its products, its ability to market and commercialize its products and new products that it may develop, technology development, scalability of technology and production, ability to attract and retain key personnel, concentration of customers and suppliers, deployment risks and integration of acquisitions, pending or threatened litigation, and the impact of COVID-19, and any variants on its business. The Company previously obtained equity financing through it’s At the Market Offering Agreement (“ATM”) with A.G.P/Alliance Global Partners (“AGP”) and through its equity line financing with Aspire Capital Fund, LLC (“Aspire Capital”), but the Company cannot be sure that additional equity and/or debt financing will be available to the Company as needed on acceptable terms, or at all. For fiscal year 2022 to date, management has not obtained any additional capital financing. Management believes the Company’s current cash balance of $7.9 million and short term investments balance of $49.4 million is sufficient to fund its planned operations through at least July 2023.

On January 7, 2019, the Company entered into an At the Market Offering Agreement with AGP (the “2019 ATM Facility”), under which the Company could issue and sell to or through AGP, acting as agent and/or principal, shares of the Company’s common stock having an aggregate offering price of up to $25.0 million. From inception of the program through its termination on December 8, 2020, under the 2019 ATM Facility, the Company sold and issued an aggregate of 17,595,472 shares of its common stock with an aggregate market value of $23.4 million at an average price of $1.33 per share, including 12,342,506 shares in fiscal year 2021 with an aggregate market value of $18.7 million at an average price of $1.51 per share and paid AGP a sales commission of approximately $0.8 million related to those shares. The agreement was fully utilized and terminated on December 8, 2020.

On November 20, 2020, the Company entered into another At the Market Offering Agreement with AGP (the “2020 ATM Facility”), having capacity up to $100.0 million. On December 4, 2020, the Company filed a prospectus with the Securities and Exchange Commission whereby, the Company could issue and sell to or through AGP, acting as agent and/or principal, shares of the Company’s common stock having an aggregate offering price of up to $50.0 million. From inception of the 2020 ATM Facility through April 30, 2022, the Company had sold and issued an aggregate of 17,179,883 shares of its common stock with an aggregate market value of $50.0 million at an average price of $2.91 per share and paid AGP a sales commission of approximately $1.6 million related to those shares. A prospectus supplement was filed on January 10, 2022 to allow the Company to sell an additional $25.0 million (or an aggregate of $75.0 million) under the 2020 ATM Facility, none of which has been sold to date.

Equity Line Common Stock Purchase Agreements

On October 24, 2019, the Company entered into a common stock purchase agreement with Aspire Capital which provided that, subject to certain terms, conditions and limitations, Aspire Capital was committed to purchase up to an aggregate of $10.0 million shares of the Company’s common stock over a 30-month period. Through September 18, 2020, the Company had sold an aggregate of 6,424,205 shares of common stock with an aggregate market value of $4.0 million at an average price of $0.63 per share pursuant to this common stock purchase agreement, including 5,025,000 shares in fiscal year 2021 with an aggregate market value of $2.9 million at an average price of $0.57 per share. The agreement was fully utilized and terminated on September 18, 2020.

On September 18, 2020, the Company entered into a new common stock purchase agreement with Aspire Capital which provided that, subject to certain terms, conditions and limitations, Aspire Capital was committed to purchase up to an aggregate of $12.5 million shares of the Company’s common stock over a 30-month period subject to a limit of 19.99% of the outstanding common stock on the date of the agreement if the price did not exceed a specified price in the agreement. The number of shares the Company could issue within the 19.99% limit was 3,722,251 shares without shareholder approval. Shareholder approval was received at the Company’s annual meeting of shareholders on December 23, 2020 for the sale of 9,864,706 additional shares of common stock to Aspire Capital, which exceeded the 19.99% limit of the outstanding common stock on the date of the agreement. Through April 30, 2022, the Company had sold, since the agreement, an aggregate of 3,722,251 shares of common stock with an aggregate market value of $11.8 million at an average price of $3.17 per share pursuant to this common stock purchase agreement with approximately $1.0 million remaining on the facility as of April 30, 2022.

Summary of Significant Accounting Policies

12 Months Ended

Apr. 30, 2022

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

(2) Summary of Significant Accounting Policies

(a) Consolidation

The accompanying consolidated financial statements include the accounts of the Company and its majority-owned subsidiaries, Ocean Power Technologies Ltd. in the United Kingdom, and Ocean Power Technologies (Australasia) Pty Ltd. in Australia, which has been liquidated as of April 30, 2022. All significant intercompany balances and transactions have been eliminated in consolidation.

(b) Use of Estimates

The preparation of the consolidated financial statements requires management of the Company to make a number of estimates and assumptions relating to the reported amounts of assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the period. Significant items subject to such estimates and assumptions include, among other items, stock-based compensation, valuations, purchase price allocations and contingent consideration related to business combinations, expected future cash flows including growth rates, discount rates, terminal values and other assumptions and estimates used to evaluate the recoverability of long-lived assets, goodwill and other intangible assets and the related amortization methods and periods, estimated hours to complete projects and percentage of completion of customer contracts for purposes of revenue recognition. Actual results could differ from those estimates.

(c) Business Combinations

The Company accounts for business combinations in accordance with Financial Accounting and Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2015-16, Business Combinations (Topic 805). The Company allocates the fair value of consideration transferred in a business combination to the estimated fair value at the acquisition date of the tangible and intangible assets acquired as well as the liabilities assumed. Acquisition costs are expensed as incurred. Any excess consideration transferred is recorded as goodwill and in instances where the fair value of consideration transferred is less than the estimated fair value of tangible and intangible assets acquired less liabilities assumed; such amounts are recorded as a gain on the bargain purchase.

(d) Revenue Recognition

A performance obligation is the unit of account for revenue recognition. The Company assesses the goods or services promised in a contract with a customer and identifies as a performance obligation either: a) a good or service (or a bundle of goods or services) that is distinct; or b) a series of distinct goods or services that are substantially the same and that have the same pattern of transfer to the customer. A contract may contain a single or multiple performance obligations. For contracts with multiple performance obligations, the Company allocates the contracted transaction price to each performance obligation based upon the relative standalone selling price, which represents the price the Company would sell a promised good or service separately to a customer. The Company determines the standalone selling price based upon the facts and circumstances of each obligated good or service. The majority of the Company’s contracts have no observable standalone selling price since the associated products and services are customized to customer specifications. As such, the standalone selling price generally reflects the Company’s forecast of the total cost to satisfy the performance obligation plus an appropriate profit margin.

The nature of the Company’s contracts may give rise to several types of variable considerations, including unpriced change orders and liquidated damages and penalties. Variable consideration can also arise from modifications to the scope of services. Variable consideration is included in the transaction price to the extent it is probable that a significant reversal of cumulative revenue recognized will not occur once the uncertainty associated with the variable consideration is resolved. Our estimates of variable consideration and determination of whether to include such amounts in the transaction price are based largely on our assessment of legal enforceability, performance and any other information (historical, current, and forecasted) that is reasonably available to us. There was no variable consideration as of April 30, 2022 or 2021. The Company presents shipping and handling costs, that occur after control of the promised goods or services transfer to the customer, as fulfillment costs rather than evaluating whether the shipping and handling activities are promised services to the customer.

The Company recognizes revenue when or as it satisfies a performance obligation by transferring a good or service to a customer, either (1) at a point in time or (2) over time. A good or service is transferred when or as the customer obtains control. The evaluation of whether control of each performance obligation is transferred at a point in time or over time is made at contract inception. Input measures such as costs incurred or time elapsed are utilized to assess progress against specific contractual performance obligations for the Company’s services. The selection of the method to measure progress towards completion requires judgment and is based on the nature of the services to be provided. For the Company, the input method using costs incurred or labor hours best represents the measure of progress against the performance obligations incorporated within the contractual agreements. If estimated total costs on any contract project a loss, the Company charges the entire estimated loss to operations in the period the loss becomes known. The cumulative effect of revisions to revenue, estimated costs to complete contracts, including penalties, incentive awards, change orders, claims, anticipated losses, and others are recorded in the accounting period in which the events indicating a loss are known and the loss can be reasonably estimated. These loss projects are re-assessed for each subsequent reporting period until the project is complete. Such revisions could occur at any time and the effects may be material.

The Company’s contracts are either cost plus or fixed price contracts. Under cost plus contracts, customers are billed for actual expenses incurred plus an agreed-upon fee. Under cost plus contracts, a profit or loss on a project is recognized depending on whether actual costs are more or less than the agreed upon amount.

The Company has two types of fixed price contracts, firm fixed price and cost-sharing. Under firm fixed price contracts, the Company receives an agreed-upon amount for providing products and services specified in the contract, a profit or loss is recognized depending on whether actual costs are more or less than the agreed upon amount. Under cost-sharing contracts, the fixed amount agreed upon with the customer is only intended to fund a portion of the costs on a specific project. Under cost sharing contracts, an amount corresponding to the revenue is recorded in cost of revenues, resulting in gross profit on these contracts of zero. The Company’s share of the costs is recorded as product development expense. The Company reports its disaggregation of revenue by contract type since this method best represents the Company’s business. For the twelve-month periods ended April 30, 2022 and 2021, all of the Company’s contracts were classified as firm fixed price.

As of April 30, 2022, the Company’s total remaining performance obligations, also referred to as backlog, totaled $0.6 million. The Company expects to recognize approximately 100%, or $0.6 million, of the remaining performance obligations as revenue over the next twelve months.

The Company also enters into lease arrangements for its PB3 PowerBuoy® (“PB3”) and Wave Adaptive Modular Vessels (“WAM-V^®”) with certain customers. Lease elements generally include a PB3 and components, while non-lease elements generally include engineering, monitoring and support services. In the lease arrangement, the customer is provided an option to extend the lease term or purchase the leased PB3 at some point during and/or at the end of the lease term.

The Company classifies leases as either operating or financing in accordance with the authoritative accounting guidance contained within ASC Topic 842, “Leases”. At inception of the contract, the Company evaluates the lease against the lease classification criteria within ASC Topic 842. If the direct financing or sales-type classification criteria are met, then the lease is accounted for as a finance lease, of which the Company has none. All others are treated as an operating lease.

The Company recognizes revenue from operating lease arrangements generally on a straight-line basis over the lease term and is presented in Revenues in the Consolidated Statement of Operations. The lease income for the twelve months ended April 30, 2022 and 2021 was immaterial.

(e) Cash and Cash Equivalents, Restricted Cash, Security Agreements and Investments

Cash and Cash Equivalents

The Company considers all highly liquid investments with a maturity of three months or less when purchased to be cash equivalents. The Company invests excess cash in a money market account. The following table summarizes cash and cash equivalents for the years ended April 30, 2022 and 2021:

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

Restricted Cash and Security Agreements

The Company has a letter of credit agreement with Santander Bank, N.A. (“Santander”). Cash of $154,000 is on deposit at Santander and serves as security for a letter of credit issued by Santander for the lease of warehouse/office space in Monroe Township, New Jersey. This agreement cannot be extended beyond July 31, 2025 and is cancellable at the discretion of Santander.

Santander also issued one letters of credit to subsidiaries of Enel Green Power (“EGP”) pursuant to the Company’s contracts with EGP. A letter of credit was issued in the amount of $645,000 and was reduced to $323,000 in August 2020. The second letter of credit will be reduced by $258,000 once the PB3 is fully deployed and passes final acceptance testing. The remaining restricted amount of $65,000 will be released 12 months after the buoy is fully deployed.

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.

	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
	$	8,362	$	83,634

Investments

During fiscal 2022, the Company acquired approximately $49.4 million in investment securities through Charles Schwab Bank. All investment securities consist of corporate bonds, government agency bonds, or U.S. Treasury Notes and Bonds, are investment grade rated or better, and mature within 12 months. The Company has the means and intends to hold all investments to maturity, and as such are classified as held-to-maturity investments. The total recognized interest expense on the premium we paid for the bonds as of April 30, 2022 is approximately $60,000 on an amortized cost basis of approximately $0.3 million. Additionally, there has been no other than temporary impairment on these investments.

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:

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	)

(f) Property and Equipment

Property and equipment are stated at cost, less accumulated depreciation and amortization. Depreciation and amortization are calculated using the straight-line method over the estimated useful lives (three to seven years) of the assets. Leasehold improvements are amortized using the straight-line method over the shorter of the estimated useful life of the asset or the remaining lease term. Expenses for maintenance and repairs are charged to operations as incurred. Property and equipment are also reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of the asset to estimated undiscounted future cash flows expected to be generated by the asset. If the carrying amount of the asset exceeds its estimated future cash flows, then an impairment charge is recognized in the amount by which the carrying amount of the asset exceeds the fair value of the asset.

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

(g) Foreign Exchange Gains and Losses

The Company maintains cash accounts that are denominated in British pound sterling, Euros and Australian dollars. These amounts are included in cash, cash equivalents and restricted cash on the accompanying Consolidated Balance Sheets. Such positions may result in realized and unrealized foreign exchange gains or losses from exchange rate fluctuations, which are included in “Foreign exchange (loss)/gain” in the accompanying Consolidated Statements of Operations.

(h) Concentration of Credit Risk

Financial instruments that potentially subject the Company to credit risk consist principally of trade accounts receivable, short term investments and cash. The Company believes that its credit risk is limited because the Company’s current contracts are with companies with a reliable payment history. The Company invests its excess cash in a money market fund and short term held-to maturity investment and does not believe that it is exposed to any significant risks related to its cash accounts, money market fund, or held-to maturity investments. Cash is also maintained at foreign financial institutions. Cash in foreign financial institutions as of April 30, 2022 was less than $0.1 million.

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:

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	%

The loss of, or a significant reduction in revenues from a current customer could significantly impact the Company’s financial position or results of operations. The Company does not require its customers to provide collateral.

(i) Warrant Accounting

The Company accounts for warrants issued in connection with its public offerings in accordance with the guidance FASB Topic “48 Accounting for Certain Financial Instruments with Characteristics of Both Liabilities and Equity” which provides that warrants meeting the classification of a liability award are recorded as a liability at its fair value. The warrant liabilities are subject to re-measurement at each balance sheet date using the Black-Scholes option pricing model. The Company recognizes any change in fair value in its Consolidated Statements of Operations. The Company will continue to adjust the carrying value of the warrants for changes in the estimated fair value until such time as these instruments are exercised or expire. At that time, the liabilities will be reclassified to “Additional paid-in capital”, a component of “Shareholders’ equity” on the Consolidated Balance Sheets. The pre-funded and common warrants issued in the Company’s April 8, 2019 public offering did not meet the criteria to be classified as a liability award and therefore were treated as an equity award. The Company has no warrants classified as liabilities as of April 30, 2022 and 2021.

(j) Net Loss per Common Share

Basic and diluted net loss per share for all periods presented is computed by dividing net loss by the weighted average number of shares of common stock and common stock equivalents outstanding during the period. The pre-funded warrants were determined to be common stock equivalents and have been included in the weighted average number of shares outstanding for calculation of the basic earnings per share number. Due to the Company’s net losses, potentially dilutive securities, consisting of options to purchase shares of common stock, warrants on common stock and unvested restricted stock issued to employees and non-employee directors, were excluded from the diluted loss per share calculation due to their anti-dilutive effect.

In computing diluted net loss per share on the Consolidated Statement of Operations, warrants on common stock, options to purchase shares of common stock and unvested restricted stock issued to employees and non-employee directors, totaling 6,353,422 and 5,163,020 for the years ended April 30, 2022 and 2021, respectively, were excluded from each of the computations as the effect would be anti-dilutive due to the Company’s losses.

(k) Share-Based Compensation

Costs resulting from all share-based payment transactions are recognized in the consolidated financial statements at their fair values. The aggregate share-based compensation expense recorded in the Consolidated Statements of Operations for the years ended April 30, 2022 and 2021 was approximately $1.2 million and $0.8 million, respectively.

(l) Intangibles

Intangible assets acquired in a business combination are recognized separately from goodwill and are initially recognized at their fair value at the acquisition date (which is regarded as their cost) (See also Note 18). Intangible assets are amortized over the estimated useful life of the asset on a basis that approximates the pattern of economic benefit. The trade name and customer relationship intangible are being amortized over 12 years and 10 years respectively, which is consistent with the estimated pattern of economic benefit of the assets.

Intangible assets are reviewed for impairment if indicators of potential impairment exist. There was no indication of impairment of intangible assets as of April 30, 2022.

(m) Goodwill

Goodwill is assessed for impairment using a qualitative or quantitative approach. Where the Company use a qualitative analysis, it considers factors that include historical financial performance, macroeconomic and industry conditions, and the legal and regulatory environment. If the qualitative assessment indicates that it is more likely than not that an impairment exists, then a quantitative assessment is performed. The quantitative assessment requires an analysis of several estimates including future cash flows or income consistent with management’s strategic business plans, annual sales growth rates and the selection of assumptions underlying a discount rate (weighted average cost of capital) based on market data available at the time to determine fair value of the Company. If the fair value is less than the carrying amount an impairment charge for the difference is recorded. The Company acquired goodwill as part of its purchase of MAR (Note 18). As this is the first year of the acquisition, no goodwill impairment assessment was completed however, the Company is not aware of potential triggering events that would cause an impairment analysis to be performed as of April 30, 2022.

(n) Income Taxes

Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carry forwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences and operating loss and tax credit carry forwards are expected to be recovered, settled or utilized. In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. If such event occurs, a valuation allowance is recorded. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date.

The Company recognizes the effect of income tax positions only if those positions are more likely than not of being sustained upon examination. Recognized income tax positions are measured at the largest amount that is greater than 50% likely of being realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. The Company records interest related to unrecognized tax benefits in interest expense and penalties in selling, general, and administrative expenses, to the extent incurred. Refer to Note 16 for further disclosures around our income taxes.

(o) Accumulated Other Comprehensive Loss

The functional currency for the Company’s foreign operations is the applicable local currency. The translation from the applicable foreign currencies to U.S. dollars is performed for balance sheet accounts using the exchange rates in effect at the balance sheet date and for revenue and expense accounts using an average exchange rate during the period. The unrealized gains or losses resulting from such translation are included in Accumulated Other Comprehensive Loss within Shareholders’ Equity. In fiscal 2022 the Company liquidated its subsidiary, Ocean Power Technologies (Australasia) Pty Ltd. in Australia, resulting in a loss of approximately $0.2 million.

(p) Recently Issued Accounting Standards

In June 2016, the FASB issued ASU No. 2016-13, “Financial Instruments - Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments.” This amendment replaces the incurred loss impairment methodology in current GAAP with a methodology that reflects expected credit losses on instruments within its scope, including trade receivables. This update is intended to provide financial statement users with more decision-useful information about the expected credit losses. In November 2019, the FASB issued No. 2019-10, Financial Instruments—Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842), which deferred the effective date of ASU 2016-13 for Smaller Reporting Companies for fiscal years beginning after December 15, 2022, including interim periods within those fiscal years. The Company is currently evaluating the impact of the adoption of ASU 2016-13 on its consolidated financial statements.

Account Receivable, Contract Assets, and Contract Liabilities

12 Months Ended

Apr. 30, 2022

Account Receivable Contract Assets And Contract Liabilities

Account Receivable, Contract Assets, and Contract Liabilities

(3) Account Receivable, Contract Assets, and Contract Liabilities

The following provides further details on the balance sheet accounts of accounts receivable, contract assets, and contract liabilities.

Accounts Receivable

The Company grants credit to its customers, generally without collateral, under normal payment terms (typically 30 to 60 days after invoicing). Generally, invoicing occurs after the related services are performed or control of the product has transferred to the customer. Accounts receivable represents an unconditional right to consideration arising from the Company’s performance under contracts with customers. The carrying value of such receivables represent their estimated realizable value.

Contract Assets

Significant changes in the contract assets balances during the period are as follows:

	2022			2021
	Twelve months ended April 30,
	2022			2021
	(in thousands)

Transferred to receivables from contract assets recognized at the beginning of the period	$	(190	)	$	(251	)
Revenue recognized and not billed as of the end of the period		386			190
Net change in contract assets	$	196		$	(61	)

Contract assets include unbilled amounts typically resulting from arrangements whereby the right to payment is conditioned on completing additional tasks or services for a performance obligation. The increase in contract assets is primarily a result of services performed relating to our project with MAR that was billed during the twelve months ended April 30, 2022.

Contract Liabilities

Significant changes in the contract liabilities balances during the period are as follows:

	2022			2021
	Twelve months ended April 30,
	2022			2021
	(in thousands)

Revenue recognized that was included in the contract liabilities balance as of the beginning of the period	$	—		$	(159	)
Transferred to contract assets from contract liabilities recognized at the beginning of the period		—			(6	)
Contract liabilities obtained in acquisition on MAR		(203	)		—
Payments collected for which revenue has not been recognized		129			—
Net change in contract liabilities	$	(74	)	$	(165	)

Contract liabilities consist of amounts invoiced to customers in excess of revenue recognized. The increase in contract liabilities is primarily due to payment for MAR projects during the twelve months ended April 30, 2022 for which we have not recognized revenue.

Inventory

12 Months Ended

Apr. 30, 2022

Inventory Disclosure [Abstract]

Inventory

(4) Inventory

The Company holds inventory related to the production of our WAM-V^® products.

Schedule of Inventory

	April 30, 2022		April 30, 2021
	(in thousands)
Raw Materials	$	198	$	—
Work in Process		244		—
Inventory, net	$	442	$	—

Other Current Assets

12 Months Ended

Apr. 30, 2022

Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]

Other Current Assets

(5) Other Current Assets

Other current assets consist of the following at April 30, 2022 and 2021:

Schedule of Other Current Assets

	April 30, 2022		April 30, 2021
	(in thousands)
Prepaid insurance	$	182	$	194
Prepaid software & licenses		127		93
Prepaid sales & marketing		50		37
Prepaid recruiting		—		12
Other receivables		24		21
Deposits		—		68
Prepaid expenses- other		84		62
Total other current assets	$	467	$	487

Property and Equipment

12 Months Ended

Apr. 30, 2022

Property, Plant and Equipment [Abstract]

Property and Equipment

(6) Property and Equipment

The components of property and equipment as of April 30, 2022 and 2021 consisted of the following:

	April 30, 2022			April 30, 2021
	(in thousands)
Equipment	$	615		$	291
Computer equipment & software		571			498
Office furniture & equipment		352			341
Leasehold improvements		477			474
Construction in process		15			15
Property and equipment, gross	$	2,030		$	1,619
Less: accumulated depreciation		(1,585	)		(1,213	)
Property and equipment, net	$	445		$	406

Depreciation expense was approximately $0.1 million for both years ended April 30, 2022 and 2021.

Leases

12 Months Ended

Apr. 30, 2022

Leases

Leases

(7) Leases

Lessor Information

As of April 30, 2022, the Company has one lease which has been classified as an operating lease per accounting guidance contained within Accounting Standards Codification (“ASC”) Topic 842, “Leases”. The Company’s remaining term on this operating lease is less than 7 months. The maturity of lease payments remaining on this lease is immaterial.

Lessee Information

Right-of-use asset and operating lease liabilities are recognized based on the present value of future minimum lease payments over the lease term at the commencement date. When the implicit rate of the lease is not provided or cannot be determined, the Company used the incremental borrowing rate based on the information available at the effective date to determine the present value of future payments. Lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise those options. The renewal options have not been included in the lease term as they are not reasonably certain of exercise. Lease expense for minimum lease payments is recognized on a straight- line basis over the lease term and consists of interest on the lease liability and the amortization of the right of use asset.

The Company has a lease for its facility located in Monroe Township, New Jersey that is used as warehouse/production space and the Company’s principal offices and corporate headquarters. The initial lease term is for seven years which expires in November of 2024 with an option to extend the lease for another five years. The lease is classified as an operating lease. The operating lease is included in right-of-use assets, lease liabilities- current and lease liabilities- long-term on the Company’s Consolidated Balance Sheets.

The Company also has two leases for properties located in Houston, Texas. The first was acquired as part of the 3Dent acquisition that is used as office space. The lease term is for 3 years and is set to expire in January of 2023. The lease is classified as an operating lease and included in the right-of-use assets, lease liabilities- current and lease liabilities- long-term on the Company’s Consolidated Balance Sheets.

The other Houston lease is for additional office space and was renewed for a 12-month term which ended on June 30, 2022 and is now expired. In accordance with ASC 842-20-5-2, since the lease term at the time of renewal was 12 months, the asset was recognized directly to the profit and loss statement on a straight-line basis and was not recognized as a right-of-use asset.

The Company also has a lease with the University of California Berkeley in Berkeley, California that was acquired as part of the MAR acquisition (see Note 18). The lease expired on June 30, 2022 and we are in discussions to renew this lease. As the lease expired prior to renewal, it has become a month-to-month lease in accordance with the agreement. In accordance with ASC 842-20-5-2, since the remaining lease term at the time of the acquisition of MAR was less than 12 months, the asset was not recognized as a right-of-use asset.

Variable lease expenses, if any, are recorded as incurred. The operating lease expense in the Consolidated Statement of Operations was $0.4 million and $0.3 million for the twelve months ended April 30, 2022 and 2021, respectively.

The components of lease expense in the Consolidated Statement of Operations for the twelve months ended April 30, 2022 and 2021 was as follows:

Schedule of Operating Lease Costs

	2022		2021
	Twelve months ended April 30,
	2022		2021
Operating lease cost	$	368	$	330
Short-term lease cost		35		17
Total lease cost	$	403	$	347

Information related to the Company’s right-of use assets and lease liabilities as of April 30, 2022 is as follows:

	April 30, 2022
		(in thousands)

Operating lease:
Operating right-of-use asset, net	$	752

Right-of-use liability- current		319
Right-of-use liability- long term		538
Total lease liability	$	857

Weighted average remaining lease term- operating leases		2.38 years
Weighted average discount rate- operating leases		8.3	%

Total remaining lease payments under the Company’s operating leases are as follows:

	April 30, 2022
		(in thousands)

2023	$	391
2024		362
2025		184
Total future minimum lease payments		937
Less imputed interest		(80	)
Total	$	857

Accrued Expenses

12 Months Ended

Apr. 30, 2022

Payables and Accruals [Abstract]

Accrued Expenses

(8) Accrued Expenses

Accrued expenses consisted of the following at April 30, 2022 and 2021:

Schedule of Accrued Expenses

	April 30, 2022		April 30, 2021
	(in thousands)
Project costs	$	59	$	368
Contract loss reserve		328		328
Employee incentive payments		266		283
Accrued salary and benefits		60		631
Professional Fees		30		200
Other		134		71
Accrued expenses total	$	877	$	1,881

Warrants

12 Months Ended

Apr. 30, 2022

Warrants

Warrants

(9) Warrants

Liability Classified Warrants

On June 2, 2016, the Company entered into a securities purchase agreement, which was amended on June 7, 2016 (as amended, the “June Purchase Agreement”) with certain institutional purchasers (the “June Purchasers”). Pursuant to the terms of the June Purchase Agreement, the Company sold an aggregate of 20,850 shares of common stock together with warrants to purchase up to an aggregate of 7,298 shares of common stock. Each share of common stock was sold together with a warrant to purchase 0.35 of a share of common stock at a combined purchase price of $92.00. The warrants have an exercise price of $121.60 per share, became exercisable on December 3, 2016 (“Initial Exercise Date”), and expired on December 3, 2021, five years following the Initial Exercise Date. As of the expiration date, none of the warrants had been exercised.

On July 22, 2016, the Company entered into a Second Amendment to the Purchase Agreement (the “Second Amended Purchase Agreement”) with certain institutional purchasers (the “July Purchasers”). Pursuant to the terms of the Second Amended Purchase Agreement, the Company sold an aggregate of 29,750 shares of common stock together with warrants to purchase up to an aggregate of 8,925 shares of common stock. Each share of common stock was sold together with a warrant to purchase 0.30 of a share of common stock at a combined purchase price of $135.00. The Warrants were exercisable immediately at an exercise price of $187.20 per share. The warrants expired on January 23, 2022, the fifth (5th) anniversary of the initial date of issuance date of January 23, 2017. As of the expiration date, none of the warrants had been exercised.

Equity Classified Warrants

On April 8, 2019, the Company issued and sold 1,542,000 shares of common stock and pre-funded warrants to purchase up to 3,385,680 shares of common stock and common warrants to purchase up to 4,927,680 shares of our common stock in an underwritten public offering. The public offering price for the pre-funded warrants was equal to the public offering price of the common stock, less the $0.01 per share exercise price of each warrant. The pre-funded warrants have no expiration date. As of April 30, 2022, all of the pre-funded warrants had been exercised. The common stock warrants have an exercise price of $3.85 per share and expire five years from the issuance date. As of April 30, 2022, all of the common warrants had been exercised.

The Company accounted for warrants issued in connection with its June and July 2016 public offerings in accordance with the guidance on “Accounting for Certain Financial Instruments with Characteristics of Both Liabilities and Equity” in Topic 480 which provides that the Company classify the warrant instruments as a liability at its fair value. The warrant liabilities are subject to re-measurement at each balance sheet date using the Black-Scholes option pricing model. The June and July 2016 warrants contain a feature whereby they could require the transfer of assets and therefore are classified as a liability award in accordance with the guidance in Topic 480. The pre-funded and common warrants issued in the Company’s April 8, 2019 public offering did not meet the criteria to be classified as a liability award and therefore were treated as an equity award and recorded as a component of shareholders’ equity in the Consolidated Balance Sheets.

Paycheck Protection Program Loan

12 Months Ended

Apr. 30, 2022

Debt Disclosure [Abstract]

Paycheck Protection Program Loan

(10) Paycheck Protection Program Loan

On March 27, 2020, the U.S. Government passed into law the Coronavirus Aid, Relief and Economic Security Act, or the (“CARES Act”). On May 3, 2020, the Company signed a Paycheck Protection Program (“PPP”) loan with Santander as the lender for $890,000 in support through the Small Business Association (“SBA”) under the PPP Loan. The PPP Loan was unsecured and evidenced by a note in favor of Santander and governed by a Loan Agreement with Santander. The Company received the proceeds on May 5, 2020.

The Company filed its loan forgiveness application at the end of February 2021 asking for 100% forgiveness of the loan. In June 2021, the Company was informed that its application was approved, and that the loan has now been fully forgiven. The Company recognized a gain on forgiveness of PPP loan of approximately $890,000 during the year ended April 30, 2022 as reflected on the Consolidated Statement of Operations.

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

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+ Details

Preferred Stock

12 Months Ended

Apr. 30, 2022

Equity [Abstract]

Preferred Stock

(11) Preferred Stock

The Company has authorized 5,000,000 shares of undesignated preferred stock with a par value of $0.001 per share. As of April 30, 2022, and 2021, no shares of preferred stock had been issued.

Common Stock

12 Months Ended

Apr. 30, 2022

Equity [Abstract]

Common Stock

(12) Common Stock

As of April 30, 2022, the Company had 100,000,000 shares authorized with a par value of $0.001 per share and 55,905,213 shares issued.

At the Market Offering Agreements

On January 7, 2019, the Company entered into the 2019 ATM Facility with AGP, under which the Company may issue and sell to or through A.G.P./Alliance Global Partners, acting as agent and/or principal, shares of the Company’s common stock having an aggregate offering price of up to $25.0 million. From inception of the program through its termination on December 8, 2020, under the 2019 ATM Facility, the Company sold and issued an aggregate of 17,595,472 shares of its common stock with an aggregate market value of $23.4 million at an average price of $1.33 per share, including 12,342,506 shares in fiscal year 2021 with an aggregate market value of $18.7 million at an average price of $1.51 per share and paid AGP a sales commission of approximately $0.8 million related to those shares. The agreement was fully utilized and terminated on December 8, 2020.

On November 20, 2020, the Company entered into an At the Market Offering Agreement with AGP having capacity up to $100.0 million. The Company on December 4, 2020 filed a prospectus with the Securities and Exchange Commission whereby, the Company could issue and sell to or through AGP, acting as agent and/or principal, shares of the Company’s common stock having an aggregate offering price of up to $50.0 million. From inception of the 2020 ATM Facility through April 30, 2022, the Company had sold and issued an aggregate of 17,179,883 shares of its common stock with an aggregate market value of $50.0 million at an average price of $2.91 per share and paid AGP a sales commission of approximately $1.6 million related to those shares. A prospectus supplement was filed on January 10, 2022 to allow the Company to sell an additional $25.0 million (or an aggregate of $75.0 million) under the 2020 ATM Facility, none of which has been sold to date.

Equity Line Common Stock Purchase Agreements

On October 24, 2019, the Company entered into a common stock purchase agreement with Aspire Capital which provided that, subject to certain terms, conditions and limitations, Aspire Capital was committed to purchase up to an aggregate of $10.0 million of shares of the Company’s common stock over a 30-month period. Through September 18, 2020, the Company had sold an aggregate of 6,424,205 shares of common stock with an aggregate market value of $4.0 million at an average price of $0.63 per share pursuant to this common stock purchase agreement, including 5,025,000 shares in fiscal year 2022 with an aggregate market value of $2.9 million at an average price of $0.57 per share. The agreement was fully utilized and terminated on September 18, 2020.

On September 18, 2020, the Company entered into a new common stock purchase agreement with Aspire Capital which provided that, subject to certain terms, conditions and limitations, Aspire Capital was committed to purchase up to an aggregate of $12.5 million of shares of the Company’s common stock over a 30-month period subject to a limit of 19.99% of the outstanding common stock on the date of the agreement if the price did not exceed a specified price in the agreement. The number of shares the Company could issue within the 19.99% limit is 3,722,251 shares without shareholder approval. Shareholder approval was received at the Company’s annual meeting of shareholders on December 23, 2020 for the sale of 9,864,706 additional shares of common stock which exceeds the 19.99% limit of the outstanding common stock on the date of the agreement. As of April 30, 2022, the Company had sold an aggregate of 3,722,251 shares of common stock with an aggregate market value of $11.8 million at an average price of $3.17 per share pursuant to this common stock purchase agreement with approximately $1.0 million available as of April 30, 2022.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

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+ Details

Treasury Shares

12 Months Ended

Apr. 30, 2022

Equity [Abstract]

Treasury Shares

(13) Treasury Shares

During the years ended April 30, 2022 and 2021, 2,312 and 16,789 shares of common stock, respectively, were purchased by the Company from employees to pay taxes related to the vesting of restricted stock.

Share-Based Compensation Plans

12 Months Ended

Apr. 30, 2022

Share-Based Payment Arrangement [Abstract]

Share-Based Compensation Plans

(14) Share-Based Compensation Plans

In 2015, upon approval by the Company’s shareholders, the Company’s 2015 Omnibus Incentive Plan (the “2015 Plan”) became effective. A total of 1,332,036 shares were authorized for issuance under the 2015 Omnibus Incentive Plan, including shares available for awards under the 2006 Stock Incentive Plan remaining at the time that plan terminated, or that were subject to awards under the 2006 Stock Incentive Plan that thereafter terminated by reason of expiration, forfeiture, cancellation or otherwise. If any award under the 2006 Stock Incentive Plan or 2015 Plan expires, is cancelled, terminates unexercised or is forfeited, those shares become again available for grant under the 2015 Plan. The 2015 Plan will terminate ten years after its effective date, in October 2025, but is subject to earlier termination as provided in the 2015 Plan. As of April 30, 2022, the Company had 696,627 shares available for future issuance under the 2015 Plan which reflects adjustments made for the departure of our former CEO as well as other departures.

On January 18, 2018, the Company’s Board of Directors adopted the Company’s Employment Inducement Incentive Award Plan (the “2018 Inducement Plan”) pursuant to which the Company reserved 25,000 shares of common stock for issuance under the Inducement Plan. In accordance with Rule 711(a) of the NYSE American Company Guide, awards under the Inducement Plan may only be made to individuals not previously employees of the Company (or following such individuals’ bona fide period of non-employment with the Company), as an inducement material to the individuals’ entry into employment with the Company. An award is any right to receive the Company’s common stock pursuant to the 2018 Inducement Plan, consisting of a performance share award, restricted stock award, a restricted stock unit award or a stock payment award. As of April 30, 2022, there were 11,487 shares available for grant under the 2018 Inducement Plan. On February 9, 2022 the 2018 Inducement Plan was amended to increase the authorized shares by 250,000 to 275,000.

Stock Options

The Company estimates the fair value of each stock option award granted with service-based vesting requirements, using the Black-Scholes option pricing model, assuming no dividends, and using the weighted average valuation assumptions noted in the following table. The risk-free rate is based on the U.S. Treasury yield curve in effect at the time of grant. The expected life (estimated period of time outstanding) of the stock options granted was estimated using the “simplified” method as permitted by the SEC’s Staff Accounting Bulletin No. 110, Share-Based Payment. Expected volatility was based on the Company’s historical volatility over the expected life of the stock option granted. There were 793,850 and 248,876 shares granted for the periods ended April 30, 2022 and 2021, respectively.

	Twelve months ended April 30,
	2022			2021
Risk-free interest rate		1.5	%		0.6	%
Expected dividend yield		0.0	%		0.0	%
Expected life (in years)		5.5			5.5 - 5.8
Expected volatility		121.9	%		136.5	%

The above assumptions were used to determine the weighted average per share fair value of $1.11 and $2.63 for stock options granted during the fiscal years ended April 30, 2022 and 2021, respectively.

Schedule of Stock Option Activity

	Shares Underlying Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (In Years)
Outstanding as of April 30, 2021		516,827		$	3.89		9.0
Granted		793,850		$	1.43
Exercised		(45,332	)	$	1.05
Cancelled/forfeited		(153,183	)	$	2.86
Expired		(1,806	)	$	32.62
Outstanding as of April 30, 2022		1,110,356		$	2.34		9.2
Exercisable as of April 30, 2022		297,504		$	4.65		7.8

As of April 30, 2022 and 2021, the total intrinsic value for both outstanding and exercisable options was approximately zero and $0.3 million respectively. As of April 30, 2022, approximately 813,000 additional options were unvested, which had an intrinsic value of zero and a weighted average remaining contractual term of 9.7 years. There was approximately $0.3 million and $0.4 million of total recognized compensation cost related to stock options during each of the twelve months ended April 30, 2022 and 2021, respectively. As of April 30, 2022, there was approximately $0.8 million of total unrecognized compensation cost related to non-vested stock options granted under the plans. This cost is expected to be recognized over a weighted-average period of 2.5 years.

Performance Stock Options

In January of 2020, the Company issued 81,337 performance-based stock options to two of its executives. There were 40,666 shares vested and outstanding, which were set to expire on December 15, 2021, all of which were exercised prior to the expiration date.

In January of 2021, the Company issued 344,723 performance-based stock options to employees and executives. The awards vest over 2 years provided there is positive total shareholder return (e.g. share price increase) as measured to the closing share price on January 14, 2022 and January 14, 2023. There were 343,456 shares unvested and outstanding for the year ended April 30, 2022. None of the shares granted to our former President and CEO under this issuance vested prior to June 18, 2021, his last day of employment. These unvested shares are included in the Cancelled/forfeited figure in the table below.

The Company determined these awards contain a market-based condition and estimated the fair value using the Monte Carlo simulation model with the following assumptions:

	Twelve months ended April 30,
	2022		2021
Risk-free interest rate		N/A		1.2	%
Expected dividend yield		N/A		0.0%
Expected life (in years)		N/A		10.0
Expected volatility		N/A		76.0%- 136.5	%

The above assumptions were used to determine the weighted average per share fair value of $2.09 for performance stock options granted during the year ended April 30, 2021.

A summary of performance stock options under our stock incentive plans is detailed in the following table.

Schedule of Stock Option Activity

	Shares Underlying Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (In Years)
Outstanding as of April 30, 2021		424,790		$	2.57		9.5
Granted		66,667		$	0.62
Exercised		(40,668	)	$	1
Cancelled/forfeited		(240,667	)	$	2.61
Outstanding as of April 30, 2022		210,122		$	2.20		8.8
Exercisable as of April 30, 2022		—		$	—

As of April 30, 2022 and 2021, the total intrinsic value of outstanding and exercisable performance stock options was approximately zero and $0.1 million respectively. As of April 30, 2022, approximately 210,000 additional options were unvested, which had an intrinsic value of $29,000 and a weighted average remaining contractual term of 8.8 years. There was approximately $0.1 million and $0.1 million of total recognized compensation cost related to performance stock options during each of the twelve months ended April 30, 2022 and 2021, respectively. As of April 30, 2022, there was approximately $0.2 million of total unrecognized compensation cost related to non-vested stock options granted under the plans. This cost is expected to be recognized over a weighted-average period of 0.9 years.

Restricted Stock

Compensation expense for unvested restricted stock is generally recorded based on its market value on the date of grant and recognized ratably over the associated service and performance period. During the year ended April 30, 2022 and 2021, the Company granted 827,764 and 10,000 shares, respectively, subject to service-based vesting requirements.

A summary of unvested restricted stock under our stock incentive plans is as follows:

	Number of Shares			Weighted Average Price per Share
Issued and unvested at April 30, 2021		10,000		$	2.93
Granted		827,764		$	1.41
Vested		(10,000	)	$	2.93
Cancelled/forfeited		—		$	—
Issued and unvested at April 30, 2022		827,764		$	1.41

There was approximately $242,000 and $49,000 of total recognized compensation cost related to restricted stock for the years ended April 30, 2022 and 2021, respectively. As of April 30, 2022, there was $0.9 million of unrecognized compensation cost remaining related to unvested restricted stock granted under our plans. This cost is expected to be recognized over a weighted-average period of 1.9 years.

Fair Value Measurements

12 Months Ended

Apr. 30, 2022

Fair Value Disclosures [Abstract]

Fair Value Measurements

(15) Fair Value Measurements

ASC Topic 820,”Fair Value Measurements” states that fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Assets and liabilities that are measured at fair value are reported using a three-level fair value hierarchy that prioritizes the inputs used to measure fair value. This hierarchy maximizes the use of observable input and minimizes the use of unobservable inputs. The following is a description of the three hierarchy levels.

Level 1	Unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date.

Level 2	Inputs other than quoted prices in active markets that are observable for the asset or liability, either directly or indirectly.

Level 3	Inputs that are unobservable for the asset or liability.

Disclosure of Fair Values

The Company’s financial instruments that are not re-measured at fair value include cash, cash equivalents, restricted cash, accounts receivable, contract assets and liabilities, deposits, accounts payable, and accrued expenses. The carrying values of these financial instruments approximate their fair values and are viewed as Level 1 items. The Company’s warrant liabilities represent the only asset or liability classified financial instrument that is measured at fair value on a recurring basis.

The fair value of the Company’s short-term investments (refer to Note 2) is based on observable trading of each security which is based on Level 1 observable inputs as they are unadjusted quoted prices in active markets. The total fair value of our investments as of April 30, 2022 and 2021 were $49.0 million and zero, respectively.

The fair value of the Company’s warrant liabilities (refer to Note 9) is based on the Black-Scholes option pricing model which is based on Level 3 unobservable inputs for which there is little or no market data, requiring the Company to develop its own assumptions. The assumptions used by the Company are the quoted price of the Company’s common stock in an active market, risk-free interest rate, volatility and expected life, and assumes no dividends. Volatility is based on the actual market activity of the Company’s stock. The expected life is based on the remaining contractual term of the warrants and the risk-free interest rate is based on the implied yield available on U.S. Treasury Securities with a maturity equivalent to the expected life of the warrants. The warrants were expired as of April 30, 2022 and had a fair value near zero as of basis as of April 30, 2021.

There were no unrealized gains for the twelve months ended April 30, 2022 and 2021, respectively. When incurred, gains and losses are included within “Gain (loss) due to change in fair value of warrant liabilities” in the Consolidated Statements of Operations. The Company determined the fair value using the Black-Scholes option pricing model with the following assumptions:

	April 30, 2022		April 30, 2021
Dividend rate		N/A		0.0	%
Risk-free rate		N/A		0.01% -0.02	%
Expected life (years)		N/A		0.2 - 0.6
Expected volatility		N/A		1.498

Additionally, there is a Level 3 contingent liability in the amount of $1.6 million as the inputs are unobservable to determine this fair value. As of April 30, 2022, there has been no change in value of this contingent liability from the time that it was acquired. Refer to Note 18 for further details around this contingent liability and how the value is determined.

Transfers into or out of any hierarchy level are recognized at the end of the reporting period in which the transfers occurred. There were no transfers between any hierarchy levels during each of the twelve months ended April 30, 2022 and 2021.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Income Taxes

12 Months Ended

Apr. 30, 2022

Income Tax Disclosure [Abstract]

Income Taxes

(16) Income Taxes

Loss before income taxes for the years ended April 30, 2022 and 2021 consisted of the following components:

	April 30, 2022			April 30, 2021
	(in thousands)
Domestic	$	(20,665	)	$	(14,392	)
Foreign		(32	)		(368	)
Total loss before income taxes	$	(20,697	)	$	(14,760	)

The income tax benefit for the years ended April 30, 2022 and 2021 consisted of state income tax benefits of $1.4 million and zero in each year, respectively, from the sale of New Jersey net operating losses and research and development credits. There was no benefit reflected in fiscal year 2021 as the payment was received in fiscal year 2022. For the year ended April 30, 2021, the income tax provision consists of state minimum tax. Also included in the income tax benefit for fiscal year 2022 is a benefit of approximately $0.4 million from the reversal of the valuation allowance resulting from the establishment of a deferred tax liability in connection with the MAR acquisition (see Note 18).

Tax Rate Reconciliation

The effective income tax rate differed from the percentages computed by applying the U.S. federal income tax rate for the periods ended April 30, 2022 and 2021 to loss before income taxes as a result of the following:

	April 30, 2022			April 30, 2021
Computed expected tax benefit		(21.0	)%		(21.0	)%
Increase(reduction) in income taxes resulting from:
State income taxes, net of federal benefit		5.2	%		6.8	%
Federal research and development tax credits		(0.6	)%		(0.7	)%
Foreign rate differential		—	%		(1.3	)%
Other non-deductible expenses		(0.9	)%		(0.6	)%
Proceeds of sale of New Jersey tax benefits		(7.0	)%		—	%
Other		1.3	%		2.3	%
Increase in valuation allowance		14.1	%		14.5	%
Income tax (benefit)		(8.9	)%		—	%

Significant Components of Deferred Taxes

The tax effects of temporary differences and carry forwards that give rise to the Company’s deferred tax assets and deferred tax liabilities are presented below.

	April 30, 2022			April 30, 2021
	(in thousands)
Deferred tax assets:
Federal net operating loss carryforwards	$	40,338		$	36,340
Foreign net operating loss carryforwards		2,061			4,064
State operating loss carryforwards		968			581
Federal and New Jersey research and development tax credits		4,167			3,303
Stock compensation		429			346
Accrued expenses		79			158
Other		(445	)		545
Net deferred tax assets before valuation allowance	$	47,597		$	45,337
Valuation allowance	$	(47,597	)		(45,091	)
Deferred tax assets	$	—		$	246

Deferred tax liability:
Other liability	$	203		$	246
Net deferred tax assets (liabilities)	$	(203	)	$	—

In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences and carry forwards become deductible or are utilized. As of April 30, 2022 and 2021, based upon the level of historical taxable losses, valuation allowances of $47.6 million and $45.1 million, respectively, were recorded to fully offset deferred tax assets. The valuation allowance increased $2.5 million during the year ended April 30, 2022 and decreased $2.7 million during the year ended 2021 respectively, due to continuing net operating losses.

As of April 30, 2022, the Company had net operating loss carry forwards for federal income tax purposes of approximately $191.4 million, which begin to expire in fiscal 2023; $56.2 million of the federal carryforward has no expiration, but the deductibility of such federal net operating losses may be limited to 80% of our taxable income in future years. The Company also had federal research and development tax credit carry forwards of approximately $3.3 million as of April 30, 2022, which begins to expire in 2024. The Tax Reform Act of 1986 contains provisions that limit the utilization of net operating loss and tax credit carry forwards if there has been an ownership change, as defined. The Company has determined that as a result of multiple ownership changes, as described in Section 382 of the Internal Revenue Code, its ability to utilize these NOL’s and research and development tax credit have been significantly limited.

In addition, as of April 30, 2022, the Company had state net operating loss carry forwards of approximately $13.8 million which begin to expire in 2041, which also may be limited to utilization limitations. Further, as of April 30, 2022, the Company had foreign net operating loss carry forwards of approximately $10.9 million. The ability to utilize these carry forwards may also be limited due to ownership changes.

Income Tax Benefit

During the years ended April 30, 2022 and 2021, the Company sold New Jersey State net operating losses and research and development credits (“NJ NOL”) in the amount of $4.0 million and $12.0 million, respectively, resulting in the recognition of income tax benefits of $0.4 million and $1.0 million. The total proceeds of $1.4 million for fiscal year 2022 and 2021 were recorded in the Company’s Statement of Operations in fiscal 2022 as the sale of the fiscal year 2021 NJ NOL was not completed until May, 2021. New Jersey-based technology or biotechnology companies with fewer than 225 US employees may be eligible to sell net operating losses and research and development tax credits to unaffiliated corporations, up to a maximum lifetime benefit of $20 million per business. As of April 30, 2022 we have approximately $4.6 million still available to sell.

Uncertain Tax Positions

The Company applies the guidance issued by the FASB for the accounting and reporting of uncertain tax positions. The guidance requires the Company to recognize in its consolidated financial statements the impact of a tax position if that position is more likely than not to be sustained upon examination, based on the technical merits of the position. The Company is currently undergoing an income tax audit in Spain for the period from 2011 to 2014, when the Company’s Spanish branch was closed. At April 30, 2022 and 2021, the Company had no other unrecognized tax positions. The Company does not expect any material increase or decrease in its income tax expense in the next twelve months, related to examinations or uncertain tax positions. Net operating loss and credit carry forwards since inception remain open to examination by taxing authorities and will continue to remain open for a period of time after utilization.

The Company does not have any interest or penalties accrued related to uncertain tax positions as it does not have any unrecognized tax benefits.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 21
-URI https://asc.fasb.org/extlink&oid=121826272&loc=d3e32857-109319

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-URI https://asc.fasb.org/extlink&oid=122134291&loc=d3e330215-122817

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 17
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=121826272&loc=d3e32809-109319

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-URI https://asc.fasb.org/extlink&oid=122134291&loc=d3e330036-122817

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI https://asc.fasb.org/extlink&oid=121826272&loc=d3e32705-109319

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
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-Section 50
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=6424409&loc=d3e44925-109338

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI https://asc.fasb.org/topic&trid=2144680

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=6424122&loc=d3e41874-109331

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-URI https://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

Commitments and Contingencies

12 Months Ended

Apr. 30, 2022

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

(17) Commitments and Contingencies

Employment Litigation

On August 28, 2018, counsel for Charles Dunleavy, the Company’s former President & Chief Executive Officer who was terminated for cause effective June 9, 2014, filed a demand for arbitration, captioned Charles F. Dunleavy v. Ocean Power Technologies, Inc., Case No. 01-18-0003-2374, before the American Arbitration Association in New Jersey. The demand alleged various claims relating to Mr. Dunleavy’s termination. After the hearings in the proceeding were conducted, on December 11, 2020, the arbitration panel issued an interim award finding, among other things, that the termination for cause of Mr. Dunleavy was in breach of his employment contract and awarded him compensatory damages in the amount of $438,255. On May 3, 2021, the panel issued a second interim award and therein awarded Mr. Dunleavy attorneys’ fees, costs and prejudgment interest. The Company agreed, on May 24, 2021, to pay Mr. Dunleavy $1,223,963, representing the total compensatory damages, attorneys’ fees, costs and prejudgment interest, which is the full amount awarded by the arbitration panel. The Company made the required payment on May 26, 2021, and the matter is now closed.

Spain Income Tax Audit

The Company underwent an income tax audit in Spain for the period from 2011 to 2014, when our Spanish branch was closed. On July 30, 2018, the Spanish tax inspector concluded that although there was no tax owed in light of losses reported, the Company’s Spanish branch owed penalties for failure to properly account for the income associated with the funding grant. During the year ended April 30, 2022, the Company received notice from the Spanish Central Economic and Administrative Tribunal that it agreed with the inspector and ruled that the Company owes the full amount of the penalty in the amount of €279,870 or approximately $331,000. On January 25, 2021, the Company paid the Spanish Tax Administration €279,870. Notwithstanding that payment, on April 30, 2022, the Company filed its appeal of the decision of the Central Court to the Spanish National Court. The Company expects a ruling on the appeal prior to the end of fiscal 2023.

Acquisition of Marine Advanced Robotics, Inc.

12 Months Ended

Apr. 30, 2022

Business Combination and Asset Acquisition [Abstract]

Acquisition of Marine Advanced Robotics, Inc.

(18) Acquisition of Marine Advanced Robotics, Inc.

On November 15, 2021, the Company acquired all of the outstanding equity interest of Marine Advanced Robotics, Inc. (“MAR”), a Richmond (San Francisco Bay Area), California-based developer and manufacturer of autonomous surface vehicles.

The Company accounted for the transaction as a business combination under ASC 805, “Business Combinations.” Accordingly, the assets and liabilities acquired were recorded at their estimated fair value on the date of acquisition. Under ASC 805, acquisition-related transaction costs of approximately $0.3 million (such as advisory, legal, valuation, other professional fees) were expensed in the Consolidated Statement of Operations in the period incurred.

The Company paid cash consideration of $4.0 million and issued 3,330,162 shares of our common stock, valued at approximately $5.9 million based on the closing price of $2.10, and reduced by a lack of marketability discount since they were restricted for a 12 month period. The Company assumed liability for advances payable to the former owners of MAR for approximately $456,000.

The contingent consideration is based on the achievement of certain milestones over a 30-month period. As of the acquisition date, the contingent consideration had a fair value of $1.6 million. Under the terms of the MAR purchase agreement, the contingent consideration consists of two earn-out periods, one running from the date of the acquisition through April 30, 2023 in which the maximum earn-out is $1.5 million and the other from May 1, 2023 through April 30, 2024 where the maximum earn-out is $2 million. The fair value as of the date of acquisition was determined using a simulation model based on an estimate of revenues during these periods and discount factors ranging from 5.8% to 14.5%. As discussed in Note 15 per ASC Topic 820, we consider this to be a Level 3 liability.

Total consideration including cash, restricted shares, liabilities assumed, and contingent consideration was valued at approximately $11.9 million.

Purchase consideration consisted of the following:

	(in thousands)
Cash	$	4,000
Advance payable - MAR		456
Fair value of restricted shares		5,855
Fair value of contingent consideration		1,591
Total consideration	$	11,902

The preliminary allocation of the fair value of the MAR acquisition is shown in the table below. The allocation of the fair value will be finalized when the valuation is completed, and the differences will be trued up for the final allocated amounts, hence, actual results may differ from preliminary estimate. In the fourth quarter of fiscal year 2022, the Company recorded a purchase accounting adjustment related to income taxes resulting in an increase to goodwill of approximately $580,000.

	(in thousands)
Total Purchase Consideration	$	11,902

Cash		12
Inventory		150
Property and equipment, net		38
Trademarks		2,755
Patents		1,193
Goodwill		8,537
Contract liabilities acquired		(203)
Deferred income tax liability		(580)
Net asset acquired	$	11,902

The net assets were recorded at their estimated fair value. In valuing acquired assets and liabilities, fair value estimates were based primarily on future expected cash flows, market rate assumptions, and appropriate discount rates. In connection with the acquisition of MAR, we acquired approximately $3.9 million of intangible assets, including trademarks with an indefinite life and patents that will be amortized over a useful life of nine years.

Goodwill is considered an indefinite-lived asset that relates primarily to intangible assets that do not qualify for separate recognition.

The unaudited pro forma financial information in the table below summarizes the combined results of operations for the Company and MAR as if the companies had been combined as of May 1, 2020. The following unaudited pro forma financial information is for informational purposes only and is not necessarily indicative of the results of operations that would have been achieved as if the acquisition had taken place as of May 1, 2020.

	$	2022		$	2021
	Twelve months ended April 30,
	2022			2021
Revenue	$	2,621		$	2,302
Net loss	$	(18,413	)	$	(14,174	)
Basic and diluted net loss per share	$	(0.34	)	$	(0.47	)

Operating Segments and Geographic Information

12 Months Ended

Apr. 30, 2022

Segment Reporting [Abstract]

Operating Segments and Geographic Information

(19) Operating Segments and Geographic Information

The Company’s business consists of one segment as the revenues associated with its different business lines are not material enough to justify segment reporting or to make it meaningful to investors, and our chief operating decision maker does not view the Company’s operations on a segment basis. The Company operates on a worldwide basis with one operating company in the U.S. and one operating subsidiary in the UK and one operating subsidiary which was discontinued during 2022 in Australia. Revenues and expenses are generally attributed to the operating unit that bills the customers. Geographic information is as follows:

	Year Ended April 30, 2022
	North & South America			Europe			Asia and Australia			Total
	(in thousands)
Revenues from external customers	$	1,633		$	19		$	107		$	1,759
Net loss		(18,732	)		(11	)		(131	)		(18,874	)
Long-lived assets		445			—			—			445
Total assets		73,359			19			15			73,393

	Year Ended April 30, 2021
	North & South America			Europe			Asia and Australia			Total
	(in thousands)
Revenues from external customers	$	1,206		$	—		$	—		$	1,206
Net loss		(13,211	)		(359	)		(22	)		(13,592	)
Long-lived assets		406			—			—			406
Total assets		86,085			19			273			86,377

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 31
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8924-108599

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8981-108599

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8657-108599

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-URI https://asc.fasb.org/topic&trid=2134510

+ Details

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Apr. 30, 2022

Accounting Policies [Abstract]

Consolidation

(a) Consolidation

Use of Estimates

(b) Use of Estimates

Business Combinations

(c) Business Combinations

Revenue Recognition

(d) Revenue Recognition

Cash and Cash Equivalents, Restricted Cash, Security Agreements and Investments

(e) Cash and Cash Equivalents, Restricted Cash, Security Agreements and Investments

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

Restricted Cash and Security Agreements

	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
	$	8,362	$	83,634

Investments

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:

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	)

Property and Equipment

(f) Property and Equipment

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

Foreign Exchange Gains and Losses

(g) Foreign Exchange Gains and Losses

Concentration of Credit Risk

(h) Concentration of Credit Risk

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	%

Warrant Accounting

(i) Warrant Accounting

Net Loss per Common Share

(j) Net Loss per Common Share

Share-Based Compensation

(k) Share-Based Compensation

Intangibles

(l) Intangibles

Intangible assets are reviewed for impairment if indicators of potential impairment exist. There was no indication of impairment of intangible assets as of April 30, 2022.

Goodwill

(m) Goodwill

Income Taxes

(n) Income Taxes

Accumulated Other Comprehensive Loss

(o) Accumulated Other Comprehensive Loss

Recently Issued Accounting Standards

(p) Recently Issued Accounting Standards

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Apr. 30, 2022

Accounting Policies [Abstract]

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

	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
	$	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:

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

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

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	%

Account Receivable, Contract Assets, and Contract Liabilities (Tables)

12 Months Ended

Apr. 30, 2022

Account Receivable Contract Assets And Contract Liabilities

Schedule of Significant Changes in Contract assets and Contract Liabilities

Significant changes in the contract assets balances during the period are as follows:

	2022			2021
	Twelve months ended April 30,
	2022			2021
	(in thousands)

Transferred to receivables from contract assets recognized at the beginning of the period	$	(190	)	$	(251	)
Revenue recognized and not billed as of the end of the period		386			190
Net change in contract assets	$	196		$	(61	)

Contract Liabilities

Significant changes in the contract liabilities balances during the period are as follows:

	2022			2021
	Twelve months ended April 30,
	2022			2021
	(in thousands)

Revenue recognized that was included in the contract liabilities balance as of the beginning of the period	$	—		$	(159	)
Transferred to contract assets from contract liabilities recognized at the beginning of the period		—			(6	)
Contract liabilities obtained in acquisition on MAR		(203	)		—
Payments collected for which revenue has not been recognized		129			—
Net change in contract liabilities	$	(74	)	$	(165	)

Inventory (Tables)

12 Months Ended

Apr. 30, 2022

Inventory Disclosure [Abstract]

Schedule of Inventory

The Company holds inventory related to the production of our WAM-V^® products.

Schedule of Inventory

	April 30, 2022		April 30, 2021
	(in thousands)
Raw Materials	$	198	$	—
Work in Process		244		—
Inventory, net	$	442	$	—

Other Current Assets (Tables)

12 Months Ended

Apr. 30, 2022

Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]

Schedule of Other Current Assets

Other current assets consist of the following at April 30, 2022 and 2021:

Schedule of Other Current Assets

	April 30, 2022		April 30, 2021
	(in thousands)
Prepaid insurance	$	182	$	194
Prepaid software & licenses		127		93
Prepaid sales & marketing		50		37
Prepaid recruiting		—		12
Other receivables		24		21
Deposits		—		68
Prepaid expenses- other		84		62
Total other current assets	$	467	$	487

Property and Equipment (Tables)

12 Months Ended

Apr. 30, 2022

Property, Plant and Equipment [Abstract]

Schedule of Components of Property and Equipment

The components of property and equipment as of April 30, 2022 and 2021 consisted of the following:

	April 30, 2022			April 30, 2021
	(in thousands)
Equipment	$	615		$	291
Computer equipment & software		571			498
Office furniture & equipment		352			341
Leasehold improvements		477			474
Construction in process		15			15
Property and equipment, gross	$	2,030		$	1,619
Less: accumulated depreciation		(1,585	)		(1,213	)
Property and equipment, net	$	445		$	406

Leases (Tables)

12 Months Ended

Apr. 30, 2022

Leases

Schedule of Right-of Use Assets and Lease Liabilities

The components of lease expense in the Consolidated Statement of Operations for the twelve months ended April 30, 2022 and 2021 was as follows:

Schedule of Operating Lease Costs

	2022		2021
	Twelve months ended April 30,
	2022		2021
Operating lease cost	$	368	$	330
Short-term lease cost		35		17
Total lease cost	$	403	$	347

Information related to the Company’s right-of use assets and lease liabilities as of April 30, 2022 is as follows:

	April 30, 2022
		(in thousands)

Operating lease:
Operating right-of-use asset, net	$	752

Right-of-use liability- current		319
Right-of-use liability- long term		538
Total lease liability	$	857

Weighted average remaining lease term- operating leases		2.38 years
Weighted average discount rate- operating leases		8.3	%

Schedule of Right-of Use Assets and Lease Liabilities

Information related to the Company’s right-of use assets and lease liabilities as of April 30, 2022 is as follows:

	April 30, 2022
		(in thousands)

Operating lease:
Operating right-of-use asset, net	$	752

Right-of-use liability- current		319
Right-of-use liability- long term		538
Total lease liability	$	857

Weighted average remaining lease term- operating leases		2.38 years
Weighted average discount rate- operating leases		8.3	%

Schedule of Future Minimum Lease Payments Under Operating Lease

Total remaining lease payments under the Company’s operating leases are as follows:

	April 30, 2022
		(in thousands)

2023	$	391
2024		362
2025		184
Total future minimum lease payments		937
Less imputed interest		(80	)
Total	$	857

Accrued Expenses (Tables)

12 Months Ended

Apr. 30, 2022

Payables and Accruals [Abstract]

Schedule of Accrued Expenses

Accrued expenses consisted of the following at April 30, 2022 and 2021:

Schedule of Accrued Expenses

	April 30, 2022		April 30, 2021
	(in thousands)
Project costs	$	59	$	368
Contract loss reserve		328		328
Employee incentive payments		266		283
Accrued salary and benefits		60		631
Professional Fees		30		200
Other		134		71
Accrued expenses total	$	877	$	1,881

Share-Based Compensation Plans (Tables)

12 Months Ended

Apr. 30, 2022

Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]

Schedule of Stock Option Valuation Assumptions

	Twelve months ended April 30,
	2022			2021
Risk-free interest rate		1.5	%		0.6	%
Expected dividend yield		0.0	%		0.0	%
Expected life (in years)		5.5			5.5 - 5.8
Expected volatility		121.9	%		136.5	%

Schedule of Stock Option Activity

	Shares Underlying Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (In Years)
Outstanding as of April 30, 2021		516,827		$	3.89		9.0
Granted		793,850		$	1.43
Exercised		(45,332	)	$	1.05
Cancelled/forfeited		(153,183	)	$	2.86
Expired		(1,806	)	$	32.62
Outstanding as of April 30, 2022		1,110,356		$	2.34		9.2
Exercisable as of April 30, 2022		297,504		$	4.65		7.8

Schedule of Non-vested Restricted Stock Activity

A summary of unvested restricted stock under our stock incentive plans is as follows:

	Number of Shares			Weighted Average Price per Share
Issued and unvested at April 30, 2021		10,000		$	2.93
Granted		827,764		$	1.41
Vested		(10,000	)	$	2.93
Cancelled/forfeited		—		$	—
Issued and unvested at April 30, 2022		827,764		$	1.41

Performance Stock Options [Member]

Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]

Schedule of Stock Option Activity

A summary of performance stock options under our stock incentive plans is detailed in the following table.

Schedule of Stock Option Activity

	Shares Underlying Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (In Years)
Outstanding as of April 30, 2021		424,790		$	2.57		9.5
Granted		66,667		$	0.62
Exercised		(40,668	)	$	1
Cancelled/forfeited		(240,667	)	$	2.61
Outstanding as of April 30, 2022		210,122		$	2.20		8.8
Exercisable as of April 30, 2022		—		$	—

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

The Company determined these awards contain a market-based condition and estimated the fair value using the Monte Carlo simulation model with the following assumptions:

	Twelve months ended April 30,
	2022		2021
Risk-free interest rate		N/A		1.2	%
Expected dividend yield		N/A		0.0%
Expected life (in years)		N/A		10.0
Expected volatility		N/A		76.0%- 136.5	%

Fair Value Measurements (Tables)

12 Months Ended

Apr. 30, 2022

Fair Value Disclosures [Abstract]

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

	April 30, 2022		April 30, 2021
Dividend rate		N/A		0.0	%
Risk-free rate		N/A		0.01% -0.02	%
Expected life (years)		N/A		0.2 - 0.6
Expected volatility		N/A		1.498

Income Taxes (Tables)

12 Months Ended

Apr. 30, 2022

Income Tax Disclosure [Abstract]

Schedule of Components of Loss Before Income Taxes

Loss before income taxes for the years ended April 30, 2022 and 2021 consisted of the following components:

	April 30, 2022			April 30, 2021
	(in thousands)
Domestic	$	(20,665	)	$	(14,392	)
Foreign		(32	)		(368	)
Total loss before income taxes	$	(20,697	)	$	(14,760	)

Schedule of Effective Income Tax Rate Reconciliation

	April 30, 2022			April 30, 2021
Computed expected tax benefit		(21.0	)%		(21.0	)%
Increase(reduction) in income taxes resulting from:
State income taxes, net of federal benefit		5.2	%		6.8	%
Federal research and development tax credits		(0.6	)%		(0.7	)%
Foreign rate differential		—	%		(1.3	)%
Other non-deductible expenses		(0.9	)%		(0.6	)%
Proceeds of sale of New Jersey tax benefits		(7.0	)%		—	%
Other		1.3	%		2.3	%
Increase in valuation allowance		14.1	%		14.5	%
Income tax (benefit)		(8.9	)%		—	%

Schedule of Deferred Tax Assets and Liabilities

The tax effects of temporary differences and carry forwards that give rise to the Company’s deferred tax assets and deferred tax liabilities are presented below.

	April 30, 2022			April 30, 2021
	(in thousands)
Deferred tax assets:
Federal net operating loss carryforwards	$	40,338		$	36,340
Foreign net operating loss carryforwards		2,061			4,064
State operating loss carryforwards		968			581
Federal and New Jersey research and development tax credits		4,167			3,303
Stock compensation		429			346
Accrued expenses		79			158
Other		(445	)		545
Net deferred tax assets before valuation allowance	$	47,597		$	45,337
Valuation allowance	$	(47,597	)		(45,091	)
Deferred tax assets	$	—		$	246

Deferred tax liability:
Other liability	$	203		$	246
Net deferred tax assets (liabilities)	$	(203	)	$	—

Acquisition of Marine Advanced Robotics, Inc. (Tables)

12 Months Ended

Apr. 30, 2022

Business Combination and Asset Acquisition [Abstract]

Schedule of Business Combination Purchase Consideration

Purchase consideration consisted of the following:

	(in thousands)
Cash	$	4,000
Advance payable - MAR		456
Fair value of restricted shares		5,855
Fair value of contingent consideration		1,591
Total consideration	$	11,902

Schedule Of Preliminary Allocation of Fair Value Assumptions

	(in thousands)
Total Purchase Consideration	$	11,902

Cash		12
Inventory		150
Property and equipment, net		38
Trademarks		2,755
Patents		1,193
Goodwill		8,537
Contract liabilities acquired		(203)
Deferred income tax liability		(580)
Net asset acquired	$	11,902

Schedule of Pro Forma Financial Information

	$	2022		$	2021
	Twelve months ended April 30,
	2022			2021
Revenue	$	2,621		$	2,302
Net loss	$	(18,413	)	$	(14,174	)
Basic and diluted net loss per share	$	(0.34	)	$	(0.47	)

Operating Segments and Geographic Information (Tables)

12 Months Ended

Apr. 30, 2022

Segment Reporting [Abstract]

Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas

	Year Ended April 30, 2022
	North & South America			Europe			Asia and Australia			Total
	(in thousands)
Revenues from external customers	$	1,633		$	19		$	107		$	1,759
Net loss		(18,732	)		(11	)		(131	)		(18,874	)
Long-lived assets		445			—			—			445
Total assets		73,359			19			15			73,393

	Year Ended April 30, 2021
	North & South America			Europe			Asia and Australia			Total
	(in thousands)
Revenues from external customers	$	1,206		$	—		$	—		$	1,206
Net loss		(13,211	)		(359	)		(22	)		(13,592	)
Long-lived assets		406			—			—			406
Total assets		86,085			19			273			86,377

Background and Liquidity (Details Narrative) - USD ($) $ / shares in Units, $ in Thousands								12 Months Ended
	Apr. 30, 2022	Dec. 23, 2020	Nov. 20, 2020	Sep. 18, 2020	Oct. 24, 2019	Apr. 08, 2019	Jan. 07, 2019	Apr. 30, 2022	Apr. 30, 2021
Property, Plant and Equipment [Line Items]
Net Income (Loss) Attributable to Parent								$ 18,874	$ 14,760
Net Cash Provided by (Used in) Operating Activities								21,296	11,674
Cash	$ 7,900							7,900
Short-Term Investments	$ 49,384							49,384
Proceeds from initial public offering									$ 66,166
Number of common stock shares sold						1,542,000
Deferred Offering Costs			$ 100,000
Alliance Global Partners [Member]
Property, Plant and Equipment [Line Items]
Number of common stock shares sold							12,342,506
Proceeds from issuance or sale of equity, net of issuance costs							$ 18,700
Combined purchase price per share							$ 1.51
2019 ATM Facility [Member] \| Alliance Global Partners [Member]
Property, Plant and Equipment [Line Items]
Proceeds from initial public offering							$ 25,000
Number of common stock shares sold							17,595,472
Proceeds from issuance or sale of equity, net of issuance costs							$ 23,400
Combined purchase price per share							$ 1.33
Payment of sales commission							$ 800
2020 ATM Facility [Member]
Property, Plant and Equipment [Line Items]
Proceeds from issuance or sale of equity, net of issuance costs								75,000
Payment of sales commission								$ 25,000
2020 ATM Facility [Member] \| Alliance Global Partners [Member]
Property, Plant and Equipment [Line Items]
Number of common stock shares sold			17,179,883					17,179,883
Proceeds from issuance or sale of equity, net of issuance costs								$ 50,000
Combined purchase price per share	$ 2.91							$ 2.91	$ 2.91
Payment of sales commission								$ 1,600
Proceeds from initial public offering			$ 50,000
2020 ATM Facility [Member] \| Alliance Global Partners [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Aggregate purchase of common stock			$ 100,000
Stock Purchase Agreement [Member] \| Aspire Capital Fund, LLC [Member]
Property, Plant and Equipment [Line Items]
Number of common stock shares sold	3,722,251			6,424,205
Proceeds from issuance or sale of equity, net of issuance costs	$ 11,800			$ 4,000
Combined purchase price per share	$ 3.17			$ 0.63				$ 3.17
Aggregate purchase of common stock				$ 12,500
Percentage of outstanding common stock		19.99%		19.99%
Shares can be issued based upon outstanding percentage				3,722,251
Additional sales of common stock shares sold		9,864,706
Proceeds from issuance or sale of equity, net of issuance costs	$ 1,000
Stock Purchase Agreement [Member] \| Aspire Capital Fund, LLC [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Aggregate purchase of common stock					$ 10,000
Stock Purchase Agreement One [Member] \| Aspire Capital Fund, LLC [Member]
Property, Plant and Equipment [Line Items]
Number of common stock shares sold								5,025,000
Proceeds from issuance or sale of equity, net of issuance costs								$ 2,900
Combined purchase price per share	$ 0.57							$ 0.57
Management [Member]
Property, Plant and Equipment [Line Items]
Net Income (Loss) Attributable to Parent								$ 18,900	$ 14,800
Net Cash Provided by (Used in) Operating Activities								$ 21,400	$ 11,700

Schedule of Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Apr. 30, 2022	Apr. 30, 2021
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 7,885	$ 83,028
Checking and Savings Accounts [Member]
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	1,815	1,850
Money Market Funds [Member]
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 6,070	$ 81,178

Schedule of Cash and Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Apr. 30, 2022	Apr. 30, 2021
Accounting Policies [Abstract]
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 (Details) $ in Thousands	12 Months Ended
	Apr. 30, 2022 USD ($)
Accounting Policies [Abstract]
Cost or Amortized Cost	$ 49,384
Gross Unrealized Gains	81
Gross Unrealized Losses	(414)
Estimated Fair Value	49,051
Net Unrealized Gains/(Losses)	$ (333)

Schedule of Property, Plant and Equipment, Useful Life (Details)	12 Months Ended
	Apr. 30, 2022
Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (Year)	3 years
Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (Year)	7 years
Equipment [Member] \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (Year)	5 years
Equipment [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (Year)	7 years
Computer Equipment & Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (Year)	3 years
Office Furniture & Fixtures [Member] \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (Year)	3 years
Office Furniture & Fixtures [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (Year)	7 years
Equipment Under Capitalized Lease [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	Over the life of the lease
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	Shorter of the estimated useful life or lease term

Schedule of Revenue by Major Customers by Reporting Segments (Details) - Revenue Benchmark [Member] - Customer Concentration Risk [Member]	12 Months Ended
	Apr. 30, 2022	Apr. 30, 2021
Transocean Ltd [Member]
Product Information [Line Items]
Revenues, percentage	15.00%
Valaris PLC [Member]
Product Information [Line Items]
Revenues, percentage	12.00%
Diamond Offshore Drilling Inc [Member]
Product Information [Line Items]
Revenues, percentage	11.00%
Department of Energy [Member]
Product Information [Line Items]
Revenues, percentage	11.00%
Enel Green Power Chile LTDA [Member]
Product Information [Line Items]
Revenues, percentage	9.00%	61.00%
Eni SPA [Member]
Product Information [Line Items]
Revenues, percentage	1.00%	22.00%
Other [Member]
Product Information [Line Items]
Revenues, percentage	41.00%	17.00%
Customers [Member]
Product Information [Line Items]
Revenues, percentage	100.00%	100.00%

Summary of Significant Accounting Policies (Details Narrative) - USD ($)	12 Months Ended
	Apr. 30, 2022	Apr. 30, 2021	Aug. 31, 2020
Property, Plant and Equipment [Line Items]
Revenue remaining performance obligation	$ 600,000
Revenue remaining performance obligation, percentage	100.00%
Alternative Investment	$ 49,400,000
Investment Income, Net, Amortization of Discount and Premium	60,000
Investment Owned, at Cost	300,000
Cash and Cash Equivalents, at Carrying Value	$ 7,885,000	$ 83,028,000
Antidilutive securities excluded from computation of earnings per share, amount	6,353,422	5,163,020
Share based compensation	$ 1,200,000	$ 800,000
Impairment of intangible assets	$ 0
Income tax likely percentage description	greater than 50%
Liquidation of Subsidiary	$ 157,000
AUSTRALIA
Property, Plant and Equipment [Line Items]
Liquidation of Subsidiary	$ 200,000
Trade Names [Member]
Property, Plant and Equipment [Line Items]
Intangible asset estimated lives	12 years
Customer Relationships [Member]
Property, Plant and Equipment [Line Items]
Intangible asset estimated lives	10 years
Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	7 years
Santander Bank [Member]
Property, Plant and Equipment [Line Items]
Letters of credit issued amount	$ 65,000
Santander Bank [Member] \| Letter 2 [Member]
Property, Plant and Equipment [Line Items]
Letters of credit issued amount	258,000
Santander Bank [Member] \| Letter 2 [Member] \| August 2020 [Member]
Property, Plant and Equipment [Line Items]
Letters of Credit Outstanding, Amount			$ 323,000
Foreign Financial Institutions [Member] \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Cash and Cash Equivalents, at Carrying Value	100,000
Restricted Cash and Security Agreements [Member] \| Santander Bank [Member] \| Letter of Credit [Member]
Property, Plant and Equipment [Line Items]
Deposits	$ 154,000
Restricted Cash and Security Agreements [Member] \| Santander Bank [Member] \| Letter 1 [Member]
Property, Plant and Equipment [Line Items]
Letters of Credit Outstanding, Amount			$ 645,000

Schedule of Significant Changes in Contract assets and Contract Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2022	Apr. 30, 2021
Account Receivable Contract Assets And Contract Liabilities
Transferred to receivables from contract assets recognized at the beginning of the period	$ (190)	$ (251)
Revenue recognized and not billed as of the end of the period	386	190
Net change in contract assets	196	(61)
Revenue recognized that was included in the contract liabilities balance as of the beginning of the period		(159)
Transferred to contract assets from contract liabilities recognized at the beginning of the period		(6)
Contract liabilities obtained in acquisition on MAR	(203)
Payments collected for which revenue has not been recognized	129
Net change in contract liabilities	$ (74)	$ (165)

Schedule of Inventory (Details) - USD ($) $ in Thousands	Apr. 30, 2022	Apr. 30, 2021
Inventory Disclosure [Abstract]
Raw Materials	$ 198
Work in Process	244
Inventory, net	$ 442

Schedule of Other Current Assets (Details) - USD ($) $ in Thousands	Apr. 30, 2022	Apr. 30, 2021
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid insurance	$ 182	$ 194
Prepaid software & licenses	127	93
Prepaid sales & marketing	50	37
Prepaid recruiting		12
Other receivables	24	21
Deposits		68
Prepaid expenses- other	84	62
Total other current assets	$ 467	$ 487

Schedule of Components of Property and Equipment (Details) - USD ($) $ in Thousands	Apr. 30, 2022	Apr. 30, 2021
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 2,030	$ 1,619
Less: accumulated depreciation	(1,585)	(1,213)
Property and equipment, net	445	406
Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	615	291
Computer Equipment & Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	571	498
Office Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	352	341
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	477	474
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 15	$ 15

Property and Equipment (Details Narrative) - USD ($) $ in Millions	12 Months Ended
	Apr. 30, 2022	Apr. 30, 2021
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 0.1	$ 0.1

Schedule of Right-of Use Assets and Lease Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2022	Apr. 30, 2021
Leases
Operating lease cost	$ 368	$ 330
Short-term lease cost	35	17
Total lease cost	403	347
Operating right-of-use asset, net	752	1,036
Right-of-use liability- current	319	347
Right-of-use liability- long term	538	$ 819
Total lease liability	$ 857
Weighted average remaining lease term- operating leases	2 years 4 months 17 days
Weighted average discount rate- operating leases	8.30%

Schedule of Future Minimum Lease Payments Under Operating Lease (Details) $ in Thousands	Apr. 30, 2022 USD ($)
Leases
2023	$ 391
2024	362
2025	184
Total future minimum lease payments	937
Less imputed interest	(80)
Total	$ 857

Leases (Details Narrative) - USD ($) $ in Millions	12 Months Ended
Leases (Details Narrative) - USD ($) $ in Millions	Apr. 30, 2022	Apr. 30, 2021
Operating lease payments	$ 0.4	$ 0.3
3Dent Acquisition [Member]
Lessee, operating lease, option to extend	expire in January of 2023
Lessee, operating lease, term of contract	3 years
Lease Expiration Date	Jun. 30, 2022
Monroe Township [Member]
Lessee, operating lease, option to extend	The initial lease term is for seven years which expires in November of 2024 with an option to extend the lease for another five years.
Lessee, operating lease, term of contract	7 years

Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Apr. 30, 2022	Apr. 30, 2021
Payables and Accruals [Abstract]
Project costs	$ 59	$ 368
Contract loss reserve	328	328
Employee incentive payments	266	283
Accrued salary and benefits	60	631
Professional Fees	30	200
Other	134	71
Accrued expenses total	$ 877	$ 1,881

Warrants (Details Narrative) - $ / shares	Apr. 08, 2019	Jul. 22, 2016	Jun. 02, 2016
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of common stock shares sold	1,542,000
Pre-funded Warrants [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Purchase of warrants	3,385,680
Exercise price of warrants	$ 0.01
Common Warrants [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Purchase of warrants	4,927,680
Exercise price of warrants	$ 3.85
Warrants and rights outstanding, term	5 years
June Purchase Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of common stock shares sold			20,850
Purchase of warrants			7,298
Purchase of common stock warrants			0.35
Common stock combined purchase price per share			$ 92.00
Exercise price of warrants			$ 121.60
Warrants and Rights Outstanding, Maturity Date			Dec. 03, 2021
Warrants and rights outstanding, term			5 years
Number of exercised warrants			0
Second Amended Purchase Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of common stock shares sold		29,750
Purchase of warrants		8,925
Purchase of common stock warrants		0.30
Common stock combined purchase price per share		$ 135.00
Exercise price of warrants		$ 187.20
Warrants and Rights Outstanding, Maturity Date		Jan. 23, 2022
Warrants and rights outstanding, term		5 years
Number of exercised warrants		0

Paycheck Protection Program Loan (Details Narrative) - Paycheck Protection Program [Member] - USD ($)		12 Months Ended
	May 03, 2020	Apr. 30, 2022
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Proceeds from loan originations	$ 890,000
Debt forgiveness, description	The Company filed its loan forgiveness application at the end of February 2021 asking for 100% forgiveness of the loan. In June 2021, the Company was informed that its application was approved, and that the loan has now been fully forgiven. The Company recognized a gain on forgiveness of PPP loan of approximately $890,000 during the year ended April 30, 2022 as reflected on the Consolidated Statement of Operations.
Debt interest rate	100.00%
Repayments of long-term debt		$ 890,000

Preferred Stock (Details Narrative) - $ / shares	Apr. 30, 2022	Apr. 30, 2021
Equity [Abstract]
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares issued	0	0

Common Stock (Details Narrative) - USD ($) $ / shares in Units, $ in Millions							1 Months Ended	12 Months Ended
	Dec. 23, 2020	Nov. 20, 2020	Sep. 18, 2020	Oct. 24, 2019	Apr. 08, 2019	Jan. 07, 2019	Jan. 31, 2021	Apr. 30, 2022	Apr. 30, 2021
Common stock, shares authorized								100,000,000	100,000,000
Common stock, par value								$ 0.001	$ 0.001
Common stock, shares issued								55,905,213	52,479,051
Number of common stock shares sold					1,542,000
Alliance Global Partners [Member]
Number of common stock shares sold						12,342,506
Proceeds from issuance or sale of equity, net of issuance costs						$ 18.7
Combined purchase price per share						$ 1.51
2019 ATM Facility [Member] \| Alliance Global Partners [Member]
Aggregate offering price						$ 25.0
Number of common stock shares sold						17,595,472
Proceeds from issuance or sale of equity, net of issuance costs						$ 23.4
Combined purchase price per share						$ 1.33
Payment of sales commission						$ 0.8
2020 ATM Facility [Member]
Proceeds from issuance or sale of equity, net of issuance costs								$ 75.0
Payment of sales commission								25.0
2020 ATM Facility [Member] \| Alliance Global Partners [Member]
Aggregate offering price		$ 50.0						$ 50.0
Number of common stock shares sold		17,179,883						17,179,883
Proceeds from issuance or sale of equity, net of issuance costs								$ 50.0
Combined purchase price per share								$ 2.91	$ 2.91
Payment of sales commission								$ 1.6
2020 ATM Facility [Member] \| Alliance Global Partners [Member] \| Maximum [Member]
Aggregate purchase of common stock		$ 100.0
Common Stock Purchase Agreement [Member] \| Aspire Capital Fund, LLC [Member]
Number of common stock shares sold			6,424,205				3,722,251	5,025,000
Proceeds from issuance or sale of equity, net of issuance costs			$ 4.0				$ 11.8	$ 2.9
Combined purchase price per share			$ 0.63				$ 3.17	$ 0.57
Aggregate purchase of common stock			$ 12.5
[custom:PercentageOfOutstandingCommonStockLimitForShareholderApproval]	19.99%		19.99%
[custom:StockIssuedDuringPeriodSharesCanBeIssuedBasedUponOutstandingPercentage]			3,722,251
[custom:NumberOfAdditionalSharesThatCanBeIssuedUponShareholderApproval]	9,864,706
[custom:SaleOfStockConsiderationReceivedPerTransactionRemaining]								$ 1.0
Common Stock Purchase Agreement [Member] \| Aspire Capital Fund, LLC [Member] \| Maximum [Member]
Aggregate purchase of common stock				$ 10.0

Treasury Shares (Details Narrative) - shares	12 Months Ended
Treasury Shares (Details Narrative) - shares	Apr. 30, 2022	Apr. 30, 2021
Equity [Abstract]
Treasury stock, shares, acquired	2,312	16,789

Schedule of Stock Option Valuation Assumptions (Details)	12 Months Ended
	Apr. 30, 2022	Apr. 30, 2021
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected dividend yield		0.00%
Expected volatility		1.498%
Minimum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Risk-free interest rate		0.01%
Expected life (in years)		2 months 12 days
Maximum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Risk-free interest rate		0.02%
Expected life (in years)		7 months 6 days
Share-Based Payment Arrangement, Option [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Risk-free interest rate	1.50%	0.60%
Expected dividend yield	0.00%	0.00%
Expected life (in years)	5 years 6 months
Expected volatility	121.90%	136.50%
Share-Based Payment Arrangement, Option [Member] \| Minimum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected life (in years)		5 years 6 months
Share-Based Payment Arrangement, Option [Member] \| Maximum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected life (in years)		5 years 9 months 18 days

Schedule of Stock Option Activity (Details)	12 Months Ended
Schedule of Stock Option Activity (Details)	Apr. 30, 2022 $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Shares underlying options outstanding, beginning \| shares	516,827
Weighted average exercise price, beginning balance	$ 3.89
Weighted Average Remaining Contractual Term (In Years), Beginning	9 years
Shares underlying options outstanding, granted \| shares	793,850
Weighted Average Exercise Price, Granted	$ 1.43
Shares Underlying Options Outstanding, Exercised \| shares	(45,332)
Weighted Average Exercise Price, Exercised	$ 1.05
Shares Underlying Options Outstanding, Cancelled/forfeited \| shares	(153,183)
Weighted Average Exercise Price, Cancelled/forfeited	$ 2.86
Shares underlying options outstanding, expired \| shares	(1,806)
Weighted average exercise price, expired	$ 32.62
Shares underlying options outstanding, ending \| shares	1,110,356
Weighted average exercise price, ending balance	$ 2.34
Weighted Average Remaining Contractual Term (In Years), Ending	9 years 2 months 12 days
Shares Underlying Options Outstanding, Exercisable at Ending \| shares	297,504
Weighted average exercise price, exercisable at ending	$ 4.65
Weighted average remaining contractual term (in years), exercisable at ending	7 years 9 months 18 days
Weighted Average Exercise Price, Exercisable	$ 4.65
Performance Stock Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Shares underlying options outstanding, beginning \| shares	424,790
Weighted average exercise price, beginning balance	$ 2.57
Weighted Average Remaining Contractual Term (In Years), Beginning	9 years 6 months
Shares underlying options outstanding, granted \| shares	66,667
Weighted Average Exercise Price, Granted	$ 0.62
Shares Underlying Options Outstanding, Exercised \| shares	(40,668)
Weighted Average Exercise Price, Exercised	$ 1
Shares Underlying Options Outstanding, Cancelled/forfeited \| shares	(240,667)
Weighted Average Exercise Price, Cancelled/forfeited	$ 2.61
Shares underlying options outstanding, ending \| shares	210,122
Weighted average exercise price, ending balance	$ 2.20
Weighted Average Remaining Contractual Term (In Years), Ending	8 years 9 months 18 days
Shares Underlying Options Outstanding, Exercisable at Ending \| shares
Weighted average exercise price, exercisable at ending
Weighted Average Exercise Price, Exercisable

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions (Details)	12 Months Ended
	Apr. 30, 2021
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Dividend rate	0.00%
Expected volatility	1.498%
Minimum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Risk-free interest rate	0.01%
Expected life (in years)	2 months 12 days
Maximum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Risk-free interest rate	0.02%
Expected life (in years)	7 months 6 days
Performance Stock Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Risk-free interest rate	1.20%
Dividend rate	0.00%
Expected life (in years)	10 years
Performance Stock Options [Member] \| Minimum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected volatility	76.00%
Performance Stock Options [Member] \| Maximum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected volatility	136.50%

Schedule of Non-vested Restricted Stock Activity (Details) - $ / shares	12 Months Ended
	Apr. 30, 2022	Apr. 30, 2021
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of Shares, Granted	827,764	10,000
Non-vested Restricted Stock [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of Shares, Issued and unvested, Beginning	10,000
Weighted Average Price per Share, Issued and Unvested, Beginning	$ 2.93
Number of Shares, Granted	827,764
Weighted Average Price per Share, Granted	$ 1.41
Number of Shares, Vested	(10,000)
Weighted Average Price per Share, Vested	$ 2.93
Number of Shares, Cancelled/forfeited
Weighted Average Price per Share, Cancelled/forfeited
Number of Shares, Issued and Unvested, Ending	827,764	10,000
Weighted Average Price per Share, Issued and Unvested, Ending	$ 1.41	$ 2.93

Share-Based Compensation Plans (Details Narrative) - USD ($)	1 Months Ended		12 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Apr. 30, 2022	Apr. 30, 2021	Feb. 09, 2022	Feb. 08, 2022	Jan. 18, 2018	Dec. 31, 2015
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation options, grants in period, gross			793,850
Weighted average per share fair value			$ 1.11	$ 2.63
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period			827,764	10,000
Performance-based Stock Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation weighted average per share fair value				$ 2.09
Share-Based Payment Arrangement, Option [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation options, grants in period, gross			793,850	248,876
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value			$ 0	$ 300,000
Options unvested			813,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Remaining Contractual Term			9 years 8 months 12 days
Share-based payment arrangement, expense			$ 300,000	400,000
Non-vested Stock [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unrecognized compensation cost related to non-vested stock			$ 800,000
Share-based compensation of weighted-average period			2 years 6 months
Performance Stock Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation options, grants in period, gross			66,667
Shares vested and outstanding		40,666
Debt expire date		Dec. 15, 2021
Performance Shares [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value			$ 0	100,000
Options unvested			210,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Remaining Contractual Term			8 years 9 months 18 days
Share-based payment arrangement, expense			$ 100,000	100,000
Unrecognized compensation cost related to non-vested stock			$ 200,000
Share-based compensation of weighted-average period			10 months 24 days
[custom:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsUnvestedOutstandingIntrinsicValue-0]			$ 29,000
Restricted Stock [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based payment arrangement, expense			$ 242,000	$ 49,000
Share-based compensation of weighted-average period			1 year 10 months 24 days
Unrecognized compensation cost			$ 900,000
Two Executives [Member] \| Performance Stock Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation options, grants in period, gross		81,337
Employees and Executives [Member] \| Performance Stock Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation options, grants in period, gross	344,723		343,456
Stock options vesting period description	The awards vest over 2 years provided there is positive total shareholder return (e.g. share price increase) as measured to the closing share price on January 14, 2022 and January 14, 2023.
2015 Omnibus Incentive Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation arrangement shares authorized								1,332,036
2015 Omnibus Incentive Plan [Member] \| Chief Executive Officer [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Capital shares reserved for future issuance			696,627
2018 Inducement Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation arrangement shares authorized					275,000	250,000
Capital shares reserved for future issuance			11,487				25,000

Fair Value Measurements (Details Narrative) - USD ($)	Apr. 30, 2022	Nov. 15, 2021	Apr. 30, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	$ 49,000,000.0		$ 0
Fair value on a recurring basis			$ 0
Business Combination, Contingent Consideration, Liability		$ 1,600,000
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability	$ 1,600,000

Schedule of Components of Loss Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2022	Apr. 30, 2021
Income Tax Disclosure [Abstract]
Domestic	$ (20,665)	$ (14,392)
Foreign	(32)	(368)
Loss before income taxes	$ (20,697)	$ (14,760)

- Definition

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (c)
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (b)
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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-Section 50
-Paragraph 32
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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-Topic 940
-SubTopic 20
-Section 25
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=126941158&loc=d3e41242-110953

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/exampleRef
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-Name Accounting Standards Codification
-Topic 280
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Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI https://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260

+ Details

Schedule of Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Apr. 30, 2022	Apr. 30, 2021
Income Tax Disclosure [Abstract]
Computed expected tax benefit	(21.00%)	(21.00%)
State income taxes, net of federal benefit	5.20%	6.80%
Federal research and development tax credits	(0.60%)	(0.70%)
Foreign rate differential		(1.30%)
Other non-deductible expenses	(0.90%)	(0.60%)
Proceeds of sale of New Jersey tax benefits	(7.00%)
Other	1.30%	2.30%
Increase in valuation allowance	14.10%	14.50%
Income tax (benefit)	(8.90%)

Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Apr. 30, 2022	Apr. 30, 2021
Income Tax Disclosure [Abstract]
Federal net operating loss carryforwards	$ 40,338	$ 36,340
Foreign net operating loss carryforwards	2,061	4,064
State operating loss carryforwards	968	581
Federal and New Jersey research and development tax credits	4,167	3,303
Stock compensation	429	346
Accrued expenses	79	158
Other	(445)	545
Net deferred tax assets before valuation allowance	47,597	45,337
Valuation allowance	(47,597)	(45,091)
Deferred tax assets		246
Other liability	203	246
Net deferred tax assets (liabilities)	$ (203)

Income Taxes (Details Narrative) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
Income Taxes (Details Narrative) - USD ($) $ in Thousands	May 31, 2021	Apr. 30, 2022	Apr. 30, 2021
Operating Loss Carryforwards [Line Items]
Income tax benefit		$ (1,823)
Deferred tax assets, valuation allowance		47,597	45,091
Increase (decrease) in valuation allowance		2,500	2,700
Net operating loss carry forwards		$ 191,400
Operating loss carryforwards, expiration description		begin to expire in fiscal 2023;
Net operating loss subject to no expiration		$ 56,200
Operating loss carryforwards, expiration description		the deductibility of such federal net operating losses may be limited to 80% of our taxable income in future years.
Proceed from sale of loss carryforwards and tax credits	$ 1,400
Operating Income (Loss)		$ (21,613)	(13,592)
Maximum [Member]
Operating Loss Carryforwards [Line Items]
Operating Income (Loss)		4,600
US Employees [Member]
Operating Loss Carryforwards [Line Items]
Operating Income (Loss)		20,000
New Jersey Division of Taxation [Member]
Operating Loss Carryforwards [Line Items]
Income tax benefit		400	1,000
Net operating loss carry forwards		$ 4,000	$ 12,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards, expiration description		begin to expire in 2041, which also may be limited to utilization limitations.
Foreign Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carry forwards		$ 10,900
Research and Development Expense [Member]
Operating Loss Carryforwards [Line Items]
Tax credit carry forwards		3,300
Marine Advanced Robotics, Inc. [Member]
Operating Loss Carryforwards [Line Items]
Income tax benefit		$ 400

Commitments and Contingencies (Details Narrative)	May 24, 2021 USD ($)	Jan. 25, 2021 EUR (€)	Aug. 28, 2018 USD ($)	Apr. 30, 2022 USD ($)
Tax Authority, Spain [Member]
Loss Contingencies [Line Items]
Payment of tax on damages \| €		€ 279,870
Selling, General and Administrative Expenses [Member] \| Tax Authority, Spain [Member]
Loss Contingencies [Line Items]
Income tax penalties		€ 279,870		$ 331,000
Charles F. Dunleavy [Member]
Loss Contingencies [Line Items]
Loss contingency, damages sought, value \| $	$ 1,223,963		$ 438,255

Schedule of Business Combination Purchase Consideration (Details)	Nov. 15, 2021 USD ($)
Business Acquisition [Line Items]
Advance payable - MAR	$ 456,000
Marine Advanced Robotics, Inc. [Member]
Business Acquisition [Line Items]
Cash	4,000,000
Advance payable - MAR	456,000
Fair value of restricted shares	5,855,000
Fair value of contingent consideration	1,591,000
Total consideration	$ 11,902,000

Schedule Of Preliminary Allocation of Fair Value Assumptions (Details) - USD ($) $ in Thousands	Nov. 15, 2021	Apr. 30, 2022
Business Acquisition [Line Items]
Goodwill		$ 8,537
Marine Advanced Robotics, Inc. [Member]
Business Acquisition [Line Items]
Total Purchase Consideration	$ 11,902
Cash	12
Inventory	150
Property and equipment, net	38
Trademarks	2,755
Patents	1,193
Goodwill	8,537
Contract liabilities acquired	(203)
Deferred income tax liability	(580)
Net asset acquired	$ 11,902

Schedule of Pro Forma Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Apr. 30, 2022	Apr. 30, 2021
Business Combination and Asset Acquisition [Abstract]
Revenue	$ 2,621	$ 2,302
Net loss	$ (18,413)	$ (14,174)
Basic and diluted net loss per share	$ (0.34)	$ (0.47)

Acquisition of Marine Advanced Robotics, Inc. (Details Narrative) - USD ($)		3 Months Ended	12 Months Ended
	Nov. 15, 2021	Apr. 30, 2022	Apr. 30, 2022
Business Acquisition [Line Items]
Acquisition related costs	$ 300,000
Liability assumed	456,000
Business combination contingent consideration	1,600,000
Business combination maximum earnout amount	1,500,000
Total consideration	11,900,000
Intangible assets acquired			$ 3,900,000
Maximum [Member]
Business Acquisition [Line Items]
Business combination maximum earnout amount	$ 2,000,000
Revenue discount percentage	14.50%
Minimum [Member]
Business Acquisition [Line Items]
Revenue discount percentage	5.80%
Marine Advanced Robotics, Inc. [Member]
Business Acquisition [Line Items]
Cash consideration	$ 4,000,000
Liability assumed	$ 456,000
Increase in goodwill		$ 580,000
Marine Advanced Robotics, Inc. [Member] \| Restricted Stock [Member]
Business Acquisition [Line Items]
Shares issued	3,330,162
Business acquisition value	$ 5,900,000
Business Acquisition, Share Price	$ 2.10

Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2022	Apr. 30, 2021
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues from external customers	$ 1,759	$ 1,206
Net loss	(18,874)	(14,760)
Total assets	73,393	86,377
Operating Segment [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues from external customers	1,759	1,206
Net loss	(18,874)	(13,592)
Long-lived assets	445	406
Total assets	73,393	86,377
North America [Member] \| Operating Segment [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues from external customers	1,633	1,206
Net loss	(18,732)	(13,211)
Long-lived assets	445	406
Total assets	73,359	86,085
Europe [Member] \| Operating Segment [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues from external customers	19
Net loss	(11)	(359)
Long-lived assets
Total assets	19	19
Asia and Australia [Member] \| Operating Segment [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues from external customers	107
Net loss	(131)	(22)
Long-lived assets
Total assets	$ 15	$ 273

- Definition

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ 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(11))
-URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
-SubTopic 10
-Section 55
-Paragraph 10
-URI https://asc.fasb.org/extlink&oid=84165509&loc=d3e56426-112766

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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+ Details

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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