Ocean Power (OPTT) 10-Q 10 Dec 14 2015 Q2 Quarterly report Financial data

Document_And_Entity_Informatio

Document And Entity Information	6 Months Ended
	Oct. 31, 2014	Nov. 30, 2014
Entity Registrant Name	'Ocean Power Technologies, Inc.	'
Entity Central Index Key	'0001378140	'
Current Fiscal Year End Date	'--04-30	'
Entity Filer Category	'Smaller Reporting Company	'
Entity Current Reporting Status	'Yes	'
Entity Voluntary Filers	'No	'
Entity Well-known Seasoned Issuer	'No	'
Entity Common Stock, Shares Outstanding (in shares)	'	18,066,611
Document Type	'10-Q	'
Document Period End Date	31-Oct-14	'
Document Fiscal Year Focus	'2015	'
Document Fiscal Period Focus	'Q2	'
Amendment Flag	'false	'

Consolidated_Balance_Sheets_Cu

Consolidated Balance Sheets (Current Period Unaudited) (USD $)	Oct. 31, 2014	Apr. 30, 2014
ASSETS	'	'
Cash and cash equivalents	$6,238,708	$13,858,659
US Treasury obligations	16,495,278	14,493,881
Australian Renewable Energy Agency (ARENA)	534,097	6,124,960
Accounts receivable, net	'	308,731
Unbilled receivables	19,143	37,410
Other current assets	351,355	568,377
Total current assets	23,638,581	35,392,018
Property and equipment, net	265,886	317,513
Patents, net	414,151	828,298
Barclay's Bank Agreement	100,000	1,221,696
Other noncurrent assets	361,229	325,310
Total assets	24,779,847	38,084,835
LIABILITIES AND STOCKHOLDERS' EQUITY	'	'
Accounts payable	405,595	501,397
Accrued expenses	2,885,285	2,931,239
Advance payment received from customer	'	4,709,055
Unearned revenues	115,073	992,447
Current portion of long-term debt	100,000	100,000
Total current liabilities	3,505,953	9,234,138
Long-term debt	100,000	150,000
Customer Advances or Deposits, Noncurrent	600,000	600,000
Total liabilities	4,205,953	9,984,138
Ocean Power Technologies, Inc. stockholders’ equity:	'	'
Preferred stock, $0.001 par value; authorized 5,000,000 shares, none issued or outstanding	'	'
Common stock, $0.001 par value; authorized 105,000,000 shares, issued 18,098,769 and 17,593,637 shares, respectively	18,099	17,594
Treasury stock, at cost; 38,658 and 37,852 shares, respectively	-132,016	-130,707
Additional paid-in capital	180,607,639	180,454,341
Accumulated deficit	-159,292,949	-151,640,503
Accumulated other comprehensive loss	-182,530	-225,733
Total Ocean Power Technologies, Inc. stockholders’ equity	21,018,243	28,474,992
Noncontrolling interest in Ocean Power Technologies (Australasia) Pty Ltd.	-444,349	-374,295
Total equity	20,573,894	28,100,697
Total liabilities and stockholders’ equity	$24,779,847	$38,084,835

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (Unaudited) (USD $)	3 Months Ended		6 Months Ended
	Oct. 31, 2014	Oct. 31, 2013	Oct. 31, 2014	Oct. 31, 2013
Revenues	$1,747,788	$463,608	$3,288,316	$924,535
Cost of revenues	1,998,076	462,336	3,965,240	922,712
Gross (loss) profit	-250,288	1,272	-676,924	1,823
Operating expenses:	'	'	'	'
Product development costs	1,224,487	1,610,089	1,144,432	2,881,034
Selling, general and administrative costs	2,708,878	1,808,892	5,831,850	4,356,651
Total operating expenses	3,933,365	3,418,981	6,976,282	7,237,685
Operating loss	-4,183,653	-3,417,709	-7,653,206	-7,235,862
Interest (expense) income, net	3,424	2,879	-55,196	3,237
Other income	'	'	185,000	'
Foreign exchange (loss) gain	-216,249	107,357	-221,907	129,127
Net loss	-4,396,478	-3,307,473	-7,745,309	-7,103,498
Less: Net loss attributable to the noncontrolling interest in Ocean Power Technologies (Australasia) Pty Ltd.	26,784	36,916	92,863	82,971
Net loss attributable to Ocean Power Technologies, Inc.	($4,369,694)	($3,270,557)	($7,652,446)	($7,020,527)
Basic and diluted net loss per share (in dollars per share)	($0.25)	($0.31)	($0.44)	($0.67)
Weighted average shares used to compute basic and diluted net loss per share (in shares)	17,481,563	10,510,214	17,473,123	10,416,021

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Loss (Unaudited) (USD $)	3 Months Ended		6 Months Ended
	Oct. 31, 2014	Oct. 31, 2013	Oct. 31, 2014	Oct. 31, 2013
Net loss	($4,396,478)	($3,307,473)	($7,745,309)	($7,103,498)
Foreign currency translation adjustment	45,181	-52,900	43,203	-71,690
Total comprehensive loss	-4,351,297	-3,360,373	-7,702,106	-7,175,188
Comprehensive loss (income) attributable to the noncontrolling interest in Ocean Power Technologies (Australasia) Pty Ltd.	26,983	-9,214	22,809	12,905
Comprehensive loss attributable to Ocean Power Technologies,	($4,324,314)	($3,369,587)	($7,679,297)	($7,162,283)

Consolidated_Statements_of_Sto

Consolidated Statements of Stockholders' Equity (Unaudited) (USD $)	Total	Accumulated Other Comprehensive Income (Loss) [Member]	Additional Paid-in Capital [Member]	Common Stock [Member]	Noncontrolling Interest [Member]	Retained Earnings [Member]	Treasury Stock [Member]
Balance, April 30, 2014 at Apr. 30, 2014	$28,100,697	($225,733)	$180,454,341	$17,594	($374,295)	($151,640,503)	($130,707)
Balance, April 30, 2014 (in shares) at Apr. 30, 2014	'	'	'	17,593,637	'	'	-37,852
Net loss	-7,745,309	'	'	'	-92,863	-7,652,446	'
Stock based compensation	74,952	'	74,952	'	'	'	'
Issuance (forfeiture) of restricted stock, net (in shares)	'	'	'	505,132	'	'	'
Issuance (forfeiture) of restricted stock, net	78,201	'	77,696	505	'	'	'
Treasury Stock, Shares, Acquired	806	'	'	'	'	'	-806
Acquisition of treasury stock	-1,309	'	'	'	'	'	-1,309
Sale of stock	650	'	650	'	'	'	'
Other comprehensive income	66,012	43,203	'	'	22,809	'	'
Balance, October 31, 2014 at Oct. 31, 2014	$20,573,894	($182,530)	$180,607,639	$18,099	($444,349)	($159,292,949)	($132,016)
Balance, October 31, 2014 (in shares) at Oct. 31, 2014	'	'	'	18,098,769	'	'	-38,658

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (Unaudited) (USD $)	6 Months Ended
	Oct. 31, 2014	Oct. 31, 2013
Cash flows from operating activities:	'	'
Net loss	($7,745,309)	($7,103,498)
Adjustments to reconcile net loss to net cash used in operating activities	'	'
Foreign exchange loss (gain)	221,907	-129,127
Depreciation and amortization	486,640	217,079
Treasury note premium amortization	'	5,391
Compensation expense related to stock option grants & restricted stock	153,153	369,503
Changes in operating assets and liabilities:	'	'
Accounts receivable	308,731	357,244
Long-term receivables	'	212,018
Unbilled receivables	-18,267	50,484
Other current assets	291,903	-122,169
Other noncurrent assets	-131,539	-138,734
Accounts payable	-90,043	-7,040
Accrued expenses	-38,258	421,744
Return of advanced payment to ARENA	-4,709,055	'
Net cash used in operating activities	-12,110,977	-6,483,460
Cash flows from investing activities:	'	'
Purchases of marketable securities	-13,746,959	-9,497,707
Maturities of marketable securities	11,745,562	16,990,850
Restricted cash	6,712,559	-745,000
Purchases of equipment	-10,896	-21,191
Net cashed provided by investing activities	4,700,266	6,726,952
Cash flows from financing activities:	'	'
Proceeds from the sale of common stock, net of issuance costs	1,155	3,429,799
Exercise of stock options	'	8,000
Repayment of debt	-50,000	-50,000
Acquisition of treasury stock	-1,309	-6,814
Net cash (used in) provided by financing activities	-50,154	3,380,985
Effect of exchange rate changes on cash and cash equivalents	-159,086	35,019
Net (decrease) increase in cash and cash equivalents	-7,619,951	3,659,496
Cash and cash equivalents, beginning of period	13,858,659	6,372,788
Cash and cash equivalents, end of period	6,238,708	10,032,284
Supplemental disclosure of noncash investing and financing activities:	'	'
Capitalized purchases of equipment financed through accounts payable and accrued expenses	10,363	'
Long Term [Member]	'	'
Changes in operating assets and liabilities:	'	'
Unearned revenues	'	-180,757
Short Term [Member]	'	'
Changes in operating assets and liabilities:	'	'
Unearned revenues	($877,374)	($334,630)

Note_1_Background_Basis_of_Pre

Note 1 - Background, Basis of Presentation and Liquidity	6 Months Ended
	Oct. 31, 2014
Notes to Financial Statements	'
Business Description and Basis of Presentation [Text Block]	'
	(1) Background, Basis of Presentation and Liquidity
	a)	Background
	Ocean Power Technologies, Inc. (the “Company”) was incorporated in 1984 in New Jersey, commenced business operations in 1994 and re-incorporated in Delaware in 2007. The Company develops and is seeking to commercialize proprietary systems that generate electricity by harnessing the renewable energy of ocean waves. The Company markets its products in the United States and internationally. Since fiscal 2002, government agencies have accounted for a significant portion of the Company’s revenues.  These revenues were largely for the support of product development efforts. The Company’s goal is that an increased portion of its revenues be from the sale of products and maintenance services, as compared to revenue to support its product development efforts. As the Company continues to advance its proprietary technologies, it expects to continue to have a net decrease in cash from operating activities unless and until it achieves positive cash flow from the planned commercialization of its products and services.
	b)	Basis of Presentation
	The accompanying unaudited consolidated financial statements have been prepared in accordance with generally accepted accounting principles for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all the information and footnotes required by generally accepted accounting principles for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation have been included. The interim operating results are not necessarily indicative of the results for a full year or for any other interim period. Further information on potential factors that could affect the Company's financial results can be found in the Company's Annual Report on Form 10-K for the year ended April 30, 2014 filed with the Securities and Exchange Commission (“SEC”) and elsewhere in this Form 10-Q.
	c)	Liquidity
	The Company has incurred net losses and negative operating cash flows since inception. As of October 31, 2014, the Company had an accumulated deficit of $159.3 million. As of October 31, 2014, the Company’s cash and cash equivalents and marketable securities balance was approximately $22.8 million as compared to $28.4 million at April 30, 2014. Based upon the Company’s cash and cash equivalents and marketable securities balance as of October 31, 2014, the Company believes that it will be able to finance its capital requirements and operations through at least the fourth calendar quarter of 2015. In addition, as of October 31, 2014, the Company’s restricted cash balance was approximately $0.6 million, which reflects a significant decrease from the Company’s restricted cash balance of approximately $7.3 million as of April 30, 2014. See Note 2(f).
	During 2014 and 2013, the Company continued to make investments in ongoing product development efforts in anticipation of future growth. The Company’s future results of operations involve significant risks and uncertainties. Factors that could affect the Company’s future operating results and cause actual results to vary materially from expectations include, but are not limited to, risks from insufficiencies of capital, technology development, scalability of technology and production, dependence on skills of key personnel, concentration of customers and suppliers, performance of PowerBuoys, deployment risks and laws, regulations and permitting. In order to complete its future growth strategy, the Company will require additional equity and/or debt financing. There is no assurance that additional equity and/or debt financing will be available to the Company as needed. If sufficient financing is not obtained by the Company, we may be required to further curtail or limit certain product development costs, and/or selling, general and administrative activities in order to reduce our cash expenditures.
	In January 2013, we filed an S-3 Shelf. The S-3 Shelf was declared effective in February 2013. Under the S-3 Shelf, in June 2013, we established an at the market offering facility (the “ATM Facility”) with Ascendiant Capital Markets, LLC (the “Manager”) via an At the Market Offering Agreement (the “ATM Agreement”). Under the ATM Agreement, we offered and sold shares of our common stock from time to time through the Manager, acting as sales agent, in ordinary brokerage transactions at prevailing market prices. Under the ATM Facility, we issued 3,306,334 shares of our common stock at an average price to the public of $3.02 per share. Net proceeds from the ATM Facility were approximately $9,698,000 during fiscal 2014.
	Also in fiscal 2014, we entered into an underwriting agreement (the “Underwriting Agreement”) with Roth Capital Partners, LLC (the “Underwriter”) on April 4, 2014, with respect to the issuance and sale in an underwritten public offering (the “Public Offering”) of an aggregate of 3,800,000 shares of our common stock at a price to the public of $3.10 per share. The Underwriting Agreement contained customary representations, warranties and agreements by us, customary conditions to closing and indemnification obligations, and a 90 day lock-up period that limited transactions in our common stock by us. Net proceeds from the Public Offering were approximately $10,828,000.
	Form S-3 limits the aggregate market value of securities that we are permitted to offer in any 12-month period under Form S-3, whether under the ATM Agreement, the Underwriting Agreement or otherwise, to one third of our public float. Given the fiscal 2014 share sales, we fully utilized the ATM Agreement and reached the applicable limit under Form S-3. Of the $40 million authorized under the S-3 Shelf, approximately $18.2 million remains available for issuance. During the six months ended October 31, 2014, there were no proceeds from the sale of stock under the S-3 Shelf.

Note_2_Summary_of_Significant_

Note 2 - Summary of Significant Accounting Policies	6 Months Ended
	Oct. 31, 2014
Notes to Financial Statements	'
Significant Accounting Policies [Text Block]	'
	(2) Summary of Significant Accounting Policies
	(a) Consolidation and Cost Method Investment
	The accompanying consolidated financial statements include the accounts of the Company and its majority-owned subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. Participation of stockholders other than the Company in the net assets and in the earnings or losses of a consolidated subsidiary is reflected as a noncontrolling interest in the Company's
	Consolidated Balance Sheets and Statements of Operations, which adjusts the Company's consolidated results of operations to reflect only the Company's share of the earnings or losses of the consolidated subsidiary. As of October 31, 2014, there was one noncontrolling interest, consisting of 11.8% of the Company's Australian subsidiary, Ocean Power Technologies (Australasia) Pty. Ltd. (“OPTA”). OPTA owns 100% of Victorian Wave Partners Pty. Ltd. (“VWP”), which is also organized under the laws of Australia.
	In addition, the Company evaluates its relationships with other entities to identify whether they are variable interest entities, and to assess whether it is the primary beneficiary of such entities. If the determination is made that the Company is the primary beneficiary, then that entity is included in the consolidated financial statements. As of October 31, 2014, there were no such entities.
	(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 and the disclosure of contingent 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 the recoverability of the carrying amount of property and equipment and patents; valuation allowances for receivables and deferred income tax assets; estimated costs to complete for projects; and percentage of completion of customer contracts for purposes of revenue recognition. Actual results could differ from those estimates. The current economic environment, particularly the macroeconomic pressures in certain European countries, has increased the degree of uncertainty inherent in those estimates and assumptions.
	(c) Revenue Recognition
	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. Currently, 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. 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.
	Generally, the Company recognizes revenue using the percentage-of-completion method based on the ratio of costs incurred to total estimated costs at completion. In certain circumstances, revenue under contracts that have specified milestones or other performance criteria may be recognized only when the customer acknowledges that such criteria have been satisfied. In addition, recognition of revenue (and the related costs) may be deferred for fixed-price contracts until contract completion if the Company is unable to reasonably estimate the total costs of the project prior to completion. These contracts are subject to interpretation and management may make a judgment as to the amount of revenue earned and recorded. Because the Company has a small number of contracts, revisions to the percentage-of-completion determination, management interpretation or delays in meeting performance and contractual criteria or in completing projects may have a significant effect on revenue for the periods involved. Upon anticipating a loss on a contract, the Company recognizes the full amount of the anticipated loss in the current period.
	Under cost plus and firm fixed price contracts, a profit or loss on a project is recognized depending on whether actual costs are more or less than the agreed upon amount. 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.
	Unbilled receivables represent expenditures on contracts, plus applicable profit margin, not yet billed. Unbilled receivables are normally billed and collected within one year. Billings made on contracts are recorded as a reduction of unbilled receivables, and to the extent that such billings and cash collections exceed costs incurred plus applicable profit margin, they are recorded as unearned revenues.
	Most of the Company’s projects are under cost-sharing contracts.
	(d) Cash and Cash Equivalents
	Cash equivalents consist of investments in short-term financial instruments with initial maturities of three months or less from the date of purchase. Cash and cash equivalents include the following:
		31-Oct-14			30-Apr-14
	Checking and savings accounts	$	3,349,284		$	1,917,176
	Certificates of deposits and US Treasury obligations		847,039			11,499,768
	Money market funds		2,042,385			441,715
		$	6,238,708		$	13,858,659
	(e) Marketable Securities
	Marketable securities with original maturities longer than three months but that mature in less than one year from the balance sheet date are classified as current assets. Marketable securities that mature more than one year from the balance sheet date are classified as noncurrent assets. Marketable securities that the Company has the intent and ability to hold to maturity are classified as investments held-to-maturity and are reported at amortized cost. The difference between the acquisition cost and face values of held-to-maturity investments is amortized over the remaining term of the investments and added to or subtracted from the acquisition cost and interest income. As of October 31, 2014 and April 30, 2014, all of the Company’s investments were classified as held-to-maturity.
	(f) Restricted Cash and Credit Facility
	A portion of the Company’s cash is restricted under the terms of three security agreements.
	One agreement is between Ocean Power Technologies, Inc. and Barclays Bank. Under this agreement, the cash is on deposit at Barclays Bank and serves as security for letters of credit and bank guarantees that are expected to be issued by Barclays Bank on behalf of OPT LTD, one of the Company's subsidiaries, under a credit facility established by Barclays Bank for OPT LTD. The credit facility carries a fee of 1% per annum of the amount of any such obligations issued by Barclays Bank. The credit facility does not have an expiration date, but is cancelable at the discretion of the bank. During the three months ended October 31, 2014, the Company reduced the credit facility from €800,000 ($964,656) to approximately €307,000 ($387,097). As of October 31, 2014, there was €278,892 ($351,655) in letters of credit outstanding under this agreement.
	The second agreement is between Ocean Power Technologies, Inc. and the New Jersey Board of Public Utilities (NJBPU). The Company received a $500,000 recoverable grant award from the NJBPU of which $200,000 is outstanding at October 31, 2014. Under this arrangement, the Company annually assigns to the NJBPU a certificate of deposit in an amount equal
	to the outstanding grant balance. See Note 6.
	The third agreement concerns letters of credit issued by PNC Bank for the benefit of the Oregon Department of State Lands for the removal of certain of the Company’s anchoring and mooring equipment from the seabed off the coast of Oregon. During the three months ended October 31, 2014, the Company substantially completed the removal activity and reduced the letters of credit from $1,200,000 to $22,000. This letter of credit is secured by a certificate of deposit with PNC Bank and has a credit term through January 31, 2015.
	The Company had classified the initial grant funding received from the Australian Renewable Energy Agency (“ARENA”) of A$5,595,723 ($5,179,960), which includes an amount required to be submitted as goods and services tax (GST), as restricted cash as of April 30, 2014.
	During the six months ended October 31, 2014, the Company remitted the GST in the amount of A$508,702 ($470,905) to the Australian Tax Office (ATO) in accordance with local tax laws and also reclaimed this amount from the ATO during such six month period. The Company also returned the initial grant funding received of A$5,595,723 ($5,179,960) and interest of A$109,051 ($102,061) to ARENA in accordance with the Deed Of Variation and Termination of Funding Deed executed between the parties in August 2014. The Company had accrued this amount in accrued expenses and recorded this amount as restricted cash at April 30, 2014. Restricted cash includes the following:
		31-Oct-14			30-Apr-14
	Current:
	Australian Renewable Energy Agency (ARENA)	―			$	5,179,960
	NJBPU agreement		125,000			100,000
	Oregon Department of State Lands		22,000			845,000
	Barclay's Bank Agreement		387,097		―
		$	534,097		$	6,124,960
		31-Oct-14			30-Apr-14
	Long Term:
	Barclay's Bank Agreement	―			$	996,696
	NJBPU agreement		100,000			225,000
		$	100,000		$	1,221,696
	(g) Foreign Exchange Gains and Losses
	The Company has invested in certain certificates of deposit and has maintained cash accounts that are denominated in British pounds sterling, Euros and Australian dollars. These amounts are included in cash, cash equivalents, restricted cash and marketable securities on the accompanying consolidated balance sheets. Such positions may result in realized and unrealized foreign exchange gains or losses from exchange rate fluctuations, which gains and losses are included in foreign exchange loss in the accompanying consolidated statements of operations.
		Three Months Ended October 31,						Six Months Ended October 31,
		2014			2013			2014			2013
	Foreign exchange (loss) gain	$	(216,249	)	$	107,357		$	(221,907	)	$	129,127
	Foreign currency denominated certificates of deposit
	and cash accounts:
		31-Oct-14			30-Apr-14
	Restricted	$	387,097		$	6,176,656
	Unrestricted		1,748,725			1,232,111
		$	2,135,822		$	7,408,767
	(h) Long-Lived Assets
	Long-lived assets, such as property and equipment and patents subject to amortization, are 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. During the six months ended October 31, 2014, the Company reviewed its long-lived assets for impairment and estimated that the remaining useful lives, for purposes of amortizing capitalized external patent costs, should be reduced from approximately five years to one year.
	(i) Concentration of Credit Risk
	Financial instruments that potentially subject the Company to concentration of credit risk consist principally of cash balances, bank certificates of deposit and trade receivables. The Company invests its excess cash in highly liquid investments (principally, short-term bank deposits, Treasury bills, Treasury notes and money market funds) and does not believe that it is exposed to any significant risks related to its cash accounts, money market funds or certificates of deposit.
	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:
		Three months ended October 31,						Six months ended October 31,
	Customer	2014			2013			2014			2013
	US Department of Energy		65	%		22	%		38	%		24	%
	Mitsui Engineering & Shipbuilding		35	%		15	%		33	%		8	%
European Union (WavePort project)	―				61	%		29	%		46	%
UK Government's Technology Strategy Board	―			―			―				19	%
		100	%		98	%		100	%		97	%
The loss of, or a significant reduction in revenues from, any of the current customers could significantly impact the Company's financial position or results of operations. The Company does not require its customers to maintain collateral.
(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 outstanding during the period. Due to the Company's net losses, potentially dilutive securities, consisting of outstanding stock options and non-vested performance-based shares, were excluded from the diluted loss per share calculation due to their anti-dilutive effect.
In computing diluted net loss per share, options to purchase shares of common stock and non-vested restricted stock issued to employees and non-employee directors, totaling 1,649,813 for the three and six months ended October 31, 2014, and 1,493,353 for the three and six months ended October 31, 2013, were excluded from the computations as the effect would be anti-dilutive due to the Company's losses.
(k)
Recently Issued Accounting Standards
On May 28, 2014, the FASB issued ASU No. 2014-09,
Revenue from Contracts with Customers
, which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The ASU will replace most existing revenue recognition guidance in U.S. Generally Accepted Accounting Principles (“GAAP”) when it becomes effective. The new standard is effective for us on January 1, 2017. Early application is not permitted. The standard permits the use of either the retrospective or the cumulative effect transition method. We are evaluating the effect that ASU 2014-09 will have on our consolidated financial statements and related disclosures. We have not yet selected a transition method nor have we determined the effect of the standard on our ongoing financial reporting.
In August 2014, the FASB issued ASU 2014-15,
Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern
, which describes how an entity should assess its ability to meet obligations and sets rules for how this information should be disclosed in the financial statements. The standard provides accounting guidance that will be used along with existing auditing standards. The new standard applies to all entities for the first annual period ending after December 15, 2016, and interim periods thereafter. Early application is permitted.  We are evaluating the effect ASU 2014-15 will have on our consolidated financial statements and disclosures and have not yet determined the effect of the standard on our ongoing financial reporting at this time.

Note_3_Marketable_Securities

Note 3 - Marketable Securities	6 Months Ended
	Oct. 31, 2014
Notes to Financial Statements	'
Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]	'
	(3
	) Marketable Securities
	Marketable securities with initial maturities longer than three months but that mature within one year from the balance sheet date are classified as current assets and are summarized as follows:
		31-Oct-14		30-Apr-14
	US Treasury obligations	$	16,495,278	$	14,493,881

Note_4_Balance_Sheet_Detail

Note 4 - Balance Sheet Detail	6 Months Ended
	Oct. 31, 2014
Notes to Financial Statements	'
Condensed Balance Sheet [Table Text Block]	'
	(4) Balance Sheet Detail
		31-Oct-14			30-Apr-14
	Accounts receivable, net
	Accounts receivable	$	―		$	308,731
	Allowance for doubtful accounts		―			―
		$	―		$	308,731
	Patents
	Patents	$	1,536,029		$	1,536,029
	Accumulated amortization		(1,121,878	)		(707,731	)
		$	414,151		$	828,298
	Accrued expenses
	Project costs	$	669,412		$	1,263,293
	Contract loss reserve		308,343			―
	Employee incentive payments		466,480			310,370
	Accrued salary and benefits		464,766			455,909
	Legal and accounting fees		739,454			168,402
	Goods and services tax (GST) due to Australian Tax Office		―			470,905
	Other		236,830			262,360
		$	2,885,285		$	2,931,239

Note_5_Related_Party_Transacti

Note 5 - Related Party Transactions	6 Months Ended
	Oct. 31, 2014
Notes to Financial Statements	'
Related Party Transactions Disclosure [Text Block]	'
	(5) Related Party Transactions
		Three Months Ended October 31,
		2014		2013
	Related party consulting expense	$	151,875	$	―
		Six Months Ended October 31,
		2014		2013
	Related party consulting expense	$	265,688	$	―
	In April 2014, the Company entered into an Executive Transition Agreement with George W. Taylor
	,
	who was formerly employed by the Company as Executive Vice Chairman and served on the Company’s Board of Directors prior to that date. Under this agreement, Dr. Taylor will receive up to fifteen months of consulting fees at a monthly rate of $20,000. For the three and six months ended October 31, 2014, the Company recorded $60,000 and $120,000 respectively in expense relating to this agreement.
	In June 2014, the Company entered into an agreement with David L. Keller, who has served as a non-executive director of the Company since October 2013. Under this agreement, Mr. Keller serves as Interim Chief Executive Officer effective with the June 9, 2014 termination of the Company’s former Chief Executive Officer, Charles F. Dunleavy. Mr. Keller will continue in this position while the Company searches for a permanent replacement and will receive a consulting fee of $1,500 per day of services provided. For the three and six months ended October 31, 2014, the Company recorded $91,875 and $145,688 respectively in expense relating to this agreement.

Note_6_Debt

Note 6 - Debt	6 Months Ended
	Oct. 31, 2014
Notes to Financial Statements	'
Debt Disclosure [Text Block]	'
	(6) Debt
	The Company was awarded a recoverable grant totaling $500,000 from the NJBPU under the Renewable Energy Business Venture Assistance Program. Under the terms of this agreement, the amount to be repaid is a fixed monthly amount of principal only, repayable over a five-year period beginning in November 2011. The terms also required the Company to assign to the NJBPU a certificate of deposit in an amount equal to the outstanding grant balance. See Note 2(f).
		31-Oct-14			30-Apr-14
	Total debt	$	200,000		$	250,000
	Current portion of long-term debt		(100,000	)		(100,000	)
	Long-term debt	$	100,000		$	150,000

Note_7_Deferred_Credits_Payabl

Note 7 - Deferred Credits Payable	6 Months Ended
	Oct. 31, 2014
Notes to Financial Statements	'
Customer Advances and Deposits Disclosure [Text Block]	'
	(7) Deferred Credits Payable
	During the year ended April 30, 2001, in connection with the sale of common stock to an investor, the Company received $600,000 from the investor in exchange for an option to purchase up to 500,000 metric tons of carbon emissions credits generated by the Company during the years 2008 through 2012, at a 30% discount from the then-prevailing market rate. If the Company received emission credits under applicable laws and failed to sell to the investor the credits up to the full amount of emission credits covered by the option, the investor was entitled to liquidated damages equal to 30% of the aggregate market value of the shortfall in emission credits (subject to a limit on the market price of emission credits).  Under the terms of the agreement, if the Company did not become entitled under applicable laws to the full amount of emission credits covered by the option by December 31, 2012, the Company was obligated to return the option fee of $600,000, less the aggregate discount on any emission credits sold to the investor prior to such date. In December 2012, the Company and the investor agreed to extend the period for the sale of emission credits until December 31, 2017. As of October 31, 2014, the Company has not generated any emissions credits eligible for purchase under the agreement. The $600,000 has been classified as a noncurrent liability as of October 31, 2014.

Note_8_StockBased_Compensation

Note 8 - Stock-Based Compensation	6 Months Ended
	Oct. 31, 2014
Notes to Financial Statements	'
Disclosure of Compensation Related Costs, Share-based Payments [Text Block]	'
	(8) Stock-Based Compensation
	Stock-based compensation costs decreased for the three and six month periods ended October 31, 2014 versus October 31, 2013 due primarily to the termination for cause of Charles F. Dunleavy, former Chief Executive Officer, on June 9, 2014. In accordance with the Company’s 2001 Stock Plan and the 2006 Stock Incentive Plan, all vested and unvested grants are forfeited upon termination for cause. In addition, the Company issued stock-based awards during the month of October 2014, where for the prior year, stock based awards were issued during the month of June 2013. The aggregate stock-based compensation expense related to all stock-based transactions recorded in the consolidated statements of operations was approximately $153,000 and $370,000 for the six months ended October 31, 2014 and 2013, respectively.
	(a) Stock Options
	Valuation Assumptions for Options Granted During the
	Six
	Months Ended
	31-Oct-14
	and 201
	3
	The fair value of each stock option granted, for both service-based and performance-based vesting requirements, during the six months ended October 31, 2014 and 2013 was estimated at the date of grant 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 US 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. 107,
	Share-Based Payment.
	Expected volatility was based on the Company’s historical volatility for the six months ended October 31, 2014 and 2013.
		Six Months Ended October 31,
		2014			2013
	Risk-free interest rate		1.6	%		1.6	%
	Expected dividend yield		0	%		0	%
	Expected life (years)		5.5			6
	Expected volatility		85.49	%		74.61	%
	The above assumptions were used to determine the weighted average per share fair value of $0.72 and $1.11 for stock options granted during the six months ended October 31, 2014 and 2013, respectively.
	A summary of stock options under the plans is as follows:
								Weighted
								Average
					Weighted			Remaining
		Shares			Average			Contractual
		Underlying			Exercise			Term
		Options			Price			(In Years)
	Outstanding as of April 30, 2014		1,472,292		$	5.53			5.9
	Forfeited		(490,233	)		7.03
	Exercised		—			—
	Granted		115,913			1.02
	Outstanding as of October 31, 2014		1,097,972			4.39			6.2
	Exercisable as of October 31, 2014		750,390			5.79			4.9
	As of October 31, 2014, the total intrinsic value of outstanding and exercisable options was $0. As of October 31, 2014, approximately 343,000 additional options are expected to vest in the future, which options had no intrinsic value and a weighted average remaining contractual term of 8.9 years. There was approximately $75,000 and $348,000 of total recognized compensation cost related to stock options for the six months ended October 31, 2014 and 2013, respectively. As of October 31, 2014, there was approximately $250,000 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 2.2 years. The Company normally issues new shares to satisfy option exercises under these plans. Stock options outstanding as of October 31, 2014 included 115,786 stock options subject to performance-based vesting requirements.
	(b) Restricted Stock
	Compensation expense for non-vested restricted stock is historically recorded based on its market value on the date of grant and recognized over the associated service and performance period. During the six months ended October 31, 2014, the Company granted 270,513 shares subject to service-based vesting requirements and 243,999 shares subject to performance-based vesting requirements. The achievement of the performance-based grants will be based on performance of the Company’s share price to a comparable market based indicator to be determined by the Company’s Board of Directors. These 243,999 performance based shares are not included in the table below and no compensation cost will be recorded until this performance market has been determined. During the six months ended October 31, 2014, 9,380 shares of non-vested restricted stock subject to performance-based vesting requirements were forfeited in accordance with performance objectives. Restricted stock issued and unvested at October 31, 2014 included 37,329 shares of non-vested restricted stock subject to performance-based vesting requirements.
	A summary of non-vested restricted stock under the plans is as follows:
					Weighted
		Number			Average Price per
		of Shares			Share
	Issued and unvested at April 30, 2014		97,610		$	2.23
	Granted		270,513			1.03
	Forfeited		(9,380	)		2.3
	Vested		(50,901	)		2.13
	Issued and unvested at October 31, 2014		307,842			1.19
	There was approximately $78,000 and $21,000 of total recognized compensation cost related to restricted stock for the six months ended October 31, 2014 and 2013, respectively. As of October 31, 2014, there was approximately $245,000 of total unrecognized compensation cost related to non-vested restricted stock granted under the plans. This cost is expected to be recognized over a weighted average period of 3.1 years.
	(c)Treasury Stock
	During the six months ended October 31, 2014 and 2013, 806 and 4,081 shares, respectively, of common stock were purchased by the Company from employees to pay taxes related to the vesting of restricted stock.

Note_9_Commitments_and_Conting

Note 9 - Commitments and Contingencies	6 Months Ended
	Oct. 31, 2014
Notes to Financial Statements	'
Commitments and Contingencies Disclosure [Text Block]	'
	(9) Commitments and Contingencies
	(a) Litigation
	Shareholder Litigation
	:
	The Company is a defendant in four putative securities class actions pending in the United States District Court for the District of New Jersey.
	See
	Roby v. Ocean Power Technologies, Inc., et al.
	, Case No. 3:14-cv-03799-FLW-LHG;
	Chew, et al. v. Ocean Power Technologies, Inc. et. al.
	, Case No 3:14-cv-03815-MAS-DEA;
	Konstantinidis v. Ocean Power Technologies, Inc., et al.
	, Case No. 3:14-cv-04015-FLW-DEA;
	Turner v. Ocean Power Technologies, Inc., et al.
	, Case No. 3:14-cv-04592.  The Company’s former Chief Executive Officer is named as a defendant in each of the lawsuits and the Company’s Chief Financial Officer is named as a defendant in two of the lawsuits.  The complaints allege claims for violations of §10(b) and §20(a) of the Securities Exchange Act of 1934 arising out of public statements relating to a now terminated agreement between Victorian Wave Partners Pty. Ltd. and the Australian Renewable Energy Agency for the development of a wave power station (the “VWP Project”).  All four complaints seek unspecified monetary damages and other relief.  On August 12, 2014, five motions for appointment of lead plaintiff were filed.  The motions also seek to consolidate the actions.  The Court has not ruled on the motions.  The cases are still in their preliminary stages and defendants have not yet responded to the complaints.
	On July 10, 2014, the Company received a demand letter (“Demand Letter”) from an attorney claiming to represent a shareholder demanding that the Company’s Board of Directors establish an independent committee to investigate and remedy alleged breaches of fiduciary duties by the Board of Directors and management relating to the VWP Project. The Company is continuing to evaluate the Demand Letter but has also invited the attorney to participate in the Section 220 Demand process discussed below.
	The Company also received a letter, dated August 19, 2014, (the “Section 220 Demand”) from another attorney claiming to represent a shareholder demanding, pursuant to 8 Del. C. § 220, to inspect certain books and records of the Company relating to the VWP Project and the termination of Charles Dunleavy as the Company’s Chief Executive Officer.  The Company has received an additional Section 220 Demand relating to the same subject matter from an attorney claiming to represent a different shareholder. The Company has responded in writing to both Section 220 Demands, and is working with the attorneys to address relevant issues.
	Employment Litigation
	:
	On June 10, 2014, the Company announced that it had terminated Charles Dunleavy as Chief Executive Officer and as an employee of the Company, effective June 9, 2014, and that Mr. Dunleavy had also been removed from his position as Chairman of the Board of Directors.  On June 17, 2014, Mr. Dunleavy wrote to the Company stating that he had retained counsel to represent him in connection with an alleged wrongful termination of his employment.  On July 28, 2014, Mr. Dunleavy resigned from the Board and the boards of directors of the Company’s subsidiaries.  To the Company’s knowledge, as of the date of filing of this Quarterly Report on Form 10-Q, Mr. Dunleavy has not filed any claims against the Company.
	In addition, the Company is involved from time to time in certain legal actions arising in the ordinary course of business.
	(b) Spain IVA (sales tax)
	The Company received notice that the Spanish tax authorities are inquiring into its 2010 IVA (value-added tax) filing for which the Company benefitted from the offset of approximately $250,000 of input tax. The Company believes that the inquiry will find that the tax credit was properly claimed and, therefore, no liability has been recorded. The Company issued two letters of credit in the amount of €278,828 ($351,655) at the request of the Spanish tax authorities. This is a customary request during the inquiry period. In November 2014, the Company received a partial refund of the amount under dispute and continues to expect that this matter will be resolved in the Company’s favor.

Note_10_Income_Taxes

Note 10 - Income Taxes	6 Months Ended
	Oct. 31, 2014
Notes to Financial Statements	'
Income Tax Disclosure [Text Block]	'
	(10) Income Taxes
	The Company did not recognize any consolidated income tax benefit (expense) for the six month periods ended October 31, 2014 and 2013. The Company has recorded a valuation allowance to reduce its net deferred tax asset to an amount that is more likely than not to be realized in future years. Accordingly, the benefit of the net operating loss that would have been recognized was offset by changes in the valuation allowance.
	During the six months ended October 31, 2014, the Company had no material changes in uncertain tax positions.

Note_11_Operating_Segments_and

Note 11 - Operating Segments and Geographic Information	6 Months Ended
	Oct. 31, 2014
Notes to Financial Statements	'
Segment Reporting Disclosure [Text Block]	'
	(11) Operating Segments and Geographic Information
	The Company views its business as one segment, which is the development of its PowerBuoy product for wave energy applications. The Company operates on a worldwide basis with one operating company in the US, one operating subsidiary in the UK and one operating subsidiary in Australia, which are categorized below as North America, Europe, and Asia and Australia, respectively. Revenues are generally attributed to the operating unit that bills the customers.
	Geographic information is as follows:
		North America			Europe			Asia and Australia			Total
	Three months ended October 31, 2014
	Revenues from external customers	$	1,747,788		$	—		$	—		$	1,747,788
	Operating loss		(3,614,964	)		(341,804	)		(226,885	)		(4,183,653	)
	Three months ended October 31, 2013
	Revenues from external customers		460,837			2,771			—			463,608
	Operating loss		(2,714,747	)		(396,523	)		(306,439	)		(3,417,709	)
	Six months ended October 31, 2014
	Revenues from external customers		3,288,316			—			—			3,288,316
	Operating loss		(6,197,577	)		(734,672	)		(720,957	)		(7,653,206	)
	Six months ended October 31, 2013
	Revenues from external customers		748,589			175,946			—			924,535
	Operating loss		(5,837,346	)		(711,925	)		(686,591	)		(7,235,862	)
	31-Oct-14
	Long-lived assets		259,210			6,676			—			265,886
	Total assets		23,192,939			909,092			677,816			24,779,847
	30-Apr-14
	Long-lived assets		305,314			12,024			175			317,513
	Total assets	$	31,313,240		$	1,003,205		$	5,768,390		$	38,084,835

Significant_Accounting_Policie

Significant Accounting Policies (Policies)	6 Months Ended
	Oct. 31, 2014
Accounting Policies [Abstract]	'
Basis of Accounting, Policy [Policy Text Block]	'
	Basis of Presentation
	The accompanying unaudited consolidated financial statements have been prepared in accordance with generally accepted accounting principles for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all the information and footnotes required by generally accepted accounting principles for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation have been included. The interim operating results are not necessarily indicative of the results for a full year or for any other interim period. Further information on potential factors that could affect the Company's financial results can be found in the Company's Annual Report on Form 10-K for the year ended April 30, 2014 filed with the Securities and Exchange Commission (“SEC”) and elsewhere in this Form 10-Q.
Liquidity Disclosure [Policy Text Block]	'
	c)	Liquidity
	The Company has incurred net losses and negative operating cash flows since inception. As of October 31, 2014, the Company had an accumulated deficit of $159.3 million. As of October 31, 2014, the Company’s cash and cash equivalents and marketable securities balance was approximately $22.8 million as compared to $28.4 million at April 30, 2014. Based upon the Company’s cash and cash equivalents and marketable securities balance as of October 31, 2014, the Company believes that it will be able to finance its capital requirements and operations through at least the fourth calendar quarter of 2015. In addition, as of October 31, 2014, the Company’s restricted cash balance was approximately $0.6 million, which reflects a significant decrease from the Company’s restricted cash balance of approximately $7.3 million as of April 30, 2014. See Note 2(f).
	During 2014 and 2013, the Company continued to make investments in ongoing product development efforts in anticipation of future growth. The Company’s future results of operations involve significant risks and uncertainties. Factors that could affect the Company’s future operating results and cause actual results to vary materially from expectations include, but are not limited to, risks from insufficiencies of capital, technology development, scalability of technology and production, dependence on skills of key personnel, concentration of customers and suppliers, performance of PowerBuoys, deployment risks and laws, regulations and permitting. In order to complete its future growth strategy, the Company will require additional equity and/or debt financing. There is no assurance that additional equity and/or debt financing will be available to the Company as needed. If sufficient financing is not obtained by the Company, we may be required to further curtail or limit certain product development costs, and/or selling, general and administrative activities in order to reduce our cash expenditures.
	In January 2013, we filed an S-3 Shelf. The S-3 Shelf was declared effective in February 2013. Under the S-3 Shelf, in June 2013, we established an at the market offering facility (the “ATM Facility”) with Ascendiant Capital Markets, LLC (the “Manager”) via an At the Market Offering Agreement (the “ATM Agreement”). Under the ATM Agreement, we offered and sold shares of our common stock from time to time through the Manager, acting as sales agent, in ordinary brokerage transactions at prevailing market prices. Under the ATM Facility, we issued 3,306,334 shares of our common stock at an average price to the public of $3.02 per share. Net proceeds from the ATM Facility were approximately $9,698,000 during fiscal 2014.
	Also in fiscal 2014, we entered into an underwriting agreement (the “Underwriting Agreement”) with Roth Capital Partners, LLC (the “Underwriter”) on April 4, 2014, with respect to the issuance and sale in an underwritten public offering (the “Public Offering”) of an aggregate of 3,800,000 shares of our common stock at a price to the public of $3.10 per share. The Underwriting Agreement contained customary representations, warranties and agreements by us, customary conditions to closing and indemnification obligations, and a 90 day lock-up period that limited transactions in our common stock by us. Net proceeds from the Public Offering were approximately $10,828,000.
	Form S-3 limits the aggregate market value of securities that we are permitted to offer in any 12-month period under Form S-3, whether under the ATM Agreement, the Underwriting Agreement or otherwise, to one third of our public float. Given the fiscal 2014 share sales, we fully utilized the ATM Agreement and reached the applicable limit under Form S-3. Of the $40 million authorized under the S-3 Shelf, approximately $18.2 million remains available for issuance. During the six months ended October 31, 2014, there were no proceeds from the sale of stock under the S-3 Shelf.
Consolidation, Policy [Policy Text Block]	'
	(a) Consolidation and Cost Method Investment
	The accompanying consolidated financial statements include the accounts of the Company and its majority-owned subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. Participation of stockholders other than the Company in the net assets and in the earnings or losses of a consolidated subsidiary is reflected as a noncontrolling interest in the Company's
	Consolidated Balance Sheets and Statements of Operations, which adjusts the Company's consolidated results of operations to reflect only the Company's share of the earnings or losses of the consolidated subsidiary. As of October 31, 2014, there was one noncontrolling interest, consisting of 11.8% of the Company's Australian subsidiary, Ocean Power Technologies (Australasia) Pty. Ltd. (“OPTA”). OPTA owns 100% of Victorian Wave Partners Pty. Ltd. (“VWP”), which is also organized under the laws of Australia.
	In addition, the Company evaluates its relationships with other entities to identify whether they are variable interest entities, and to assess whether it is the primary beneficiary of such entities. If the determination is made that the Company is the primary beneficiary, then that entity is included in the consolidated financial statements. As of October 31, 2014, there were no such entities.
Use of Estimates, Policy [Policy Text Block]	'
	(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 and the disclosure of contingent 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 the recoverability of the carrying amount of property and equipment and patents; valuation allowances for receivables and deferred income tax assets; estimated costs to complete for projects; and percentage of completion of customer contracts for purposes of revenue recognition. Actual results could differ from those estimates. The current economic environment, particularly the macroeconomic pressures in certain European countries, has increased the degree of uncertainty inherent in those estimates and assumptions.
Revenue Recognition, Policy [Policy Text Block]	'
	(c) Revenue Recognition
	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. Currently, 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. 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.
	Generally, the Company recognizes revenue using the percentage-of-completion method based on the ratio of costs incurred to total estimated costs at completion. In certain circumstances, revenue under contracts that have specified milestones or other performance criteria may be recognized only when the customer acknowledges that such criteria have been satisfied. In addition, recognition of revenue (and the related costs) may be deferred for fixed-price contracts until contract completion if the Company is unable to reasonably estimate the total costs of the project prior to completion. These contracts are subject to interpretation and management may make a judgment as to the amount of revenue earned and recorded. Because the Company has a small number of contracts, revisions to the percentage-of-completion determination, management interpretation or delays in meeting performance and contractual criteria or in completing projects may have a significant effect on revenue for the periods involved. Upon anticipating a loss on a contract, the Company recognizes the full amount of the anticipated loss in the current period.
	Under cost plus and firm fixed price contracts, a profit or loss on a project is recognized depending on whether actual costs are more or less than the agreed upon amount. 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.
	Unbilled receivables represent expenditures on contracts, plus applicable profit margin, not yet billed. Unbilled receivables are normally billed and collected within one year. Billings made on contracts are recorded as a reduction of unbilled receivables, and to the extent that such billings and cash collections exceed costs incurred plus applicable profit margin, they are recorded as unearned revenues.
	Most of the Company’s projects are under cost-sharing contracts.
Cash and Cash Equivalents, Policy [Policy Text Block]	'
	(d) Cash and Cash Equivalents
	Cash equivalents consist of investments in short-term financial instruments with initial maturities of three months or less from the date of purchase. Cash and cash equivalents include the following:
			31-Oct-14			30-Apr-14
	Checking and savings accounts		$	3,349,284		$	1,917,176
	Certificates of deposits and US Treasury obligations			847,039			11,499,768
	Money market funds			2,042,385			441,715
			$	6,238,708		$	13,858,659
Marketable Securities, Policy [Policy Text Block]	'
	(e) Marketable Securities
	Marketable securities with original maturities longer than three months but that mature in less than one year from the balance sheet date are classified as current assets. Marketable securities that mature more than one year from the balance sheet date are classified as noncurrent assets. Marketable securities that the Company has the intent and ability to hold to maturity are classified as investments held-to-maturity and are reported at amortized cost. The difference between the acquisition cost and face values of held-to-maturity investments is amortized over the remaining term of the investments and added to or subtracted from the acquisition cost and interest income. As of October 31, 2014 and April 30, 2014, all of the Company’s investments were classified as held-to-maturity.
Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block]	'
	(f) Restricted Cash and Credit Facility
	A portion of the Company’s cash is restricted under the terms of three security agreements.
	One agreement is between Ocean Power Technologies, Inc. and Barclays Bank. Under this agreement, the cash is on deposit at Barclays Bank and serves as security for letters of credit and bank guarantees that are expected to be issued by Barclays Bank on behalf of OPT LTD, one of the Company's subsidiaries, under a credit facility established by Barclays Bank for OPT LTD. The credit facility carries a fee of 1% per annum of the amount of any such obligations issued by Barclays Bank. The credit facility does not have an expiration date, but is cancelable at the discretion of the bank. During the three months ended October 31, 2014, the Company reduced the credit facility from €800,000 ($964,656) to approximately €307,000 ($387,097). As of October 31, 2014, there was €278,892 ($351,655) in letters of credit outstanding under this agreement.
	The second agreement is between Ocean Power Technologies, Inc. and the New Jersey Board of Public Utilities (NJBPU). The Company received a $500,000 recoverable grant award from the NJBPU of which $200,000 is outstanding at October 31, 2014. Under this arrangement, the Company annually assigns to the NJBPU a certificate of deposit in an amount equal
	to the outstanding grant balance. See Note 6.
	The third agreement concerns letters of credit issued by PNC Bank for the benefit of the Oregon Department of State Lands for the removal of certain of the Company’s anchoring and mooring equipment from the seabed off the coast of Oregon. During the three months ended October 31, 2014, the Company substantially completed the removal activity and reduced the letters of credit from $1,200,000 to $22,000. This letter of credit is secured by a certificate of deposit with PNC Bank and has a credit term through January 31, 2015.
	The Company had classified the initial grant funding received from the Australian Renewable Energy Agency (“ARENA”) of A$5,595,723 ($5,179,960), which includes an amount required to be submitted as goods and services tax (GST), as restricted cash as of April 30, 2014.
	During the six months ended October 31, 2014, the Company remitted the GST in the amount of A$508,702 ($470,905) to the Australian Tax Office (ATO) in accordance with local tax laws and also reclaimed this amount from the ATO during such six month period. The Company also returned the initial grant funding received of A$5,595,723 ($5,179,960) and interest of A$109,051 ($102,061) to ARENA in accordance with the Deed Of Variation and Termination of Funding Deed executed between the parties in August 2014. The Company had accrued this amount in accrued expenses and recorded this amount as restricted cash at April 30, 2014. Restricted cash includes the following:
			31-Oct-14			30-Apr-14
	Current:
	Australian Renewable Energy Agency (ARENA)		?			$	5,179,960
	NJBPU agreement			125,000			100,000
	Oregon Department of State Lands			22,000			845,000
	Barclay's Bank Agreement			387,097		?
			$	534,097		$	6,124,960
			31-Oct-14			30-Apr-14
	Long Term:
	Barclay's Bank Agreement		?			$	996,696
	NJBPU agreement			100,000			225,000
			$	100,000		$	1,221,696
Foreign Currency Transactions and Translations Policy [Policy Text Block]	'
	(g) Foreign Exchange Gains and Losses
	The Company has invested in certain certificates of deposit and has maintained cash accounts that are denominated in British pounds sterling, Euros and Australian dollars. These amounts are included in cash, cash equivalents, restricted cash and marketable securities on the accompanying consolidated balance sheets. Such positions may result in realized and unrealized foreign exchange gains or losses from exchange rate fluctuations, which gains and losses are included in foreign exchange loss in the accompanying consolidated statements of operations.
			Three Months Ended October 31,						Six Months Ended October 31,
			2014			2013			2014			2013
	Foreign exchange (loss) gain		$	(216,249	)	$	107,357		$	(221,907	)	$	129,127
	Foreign currency denominated certificates of deposit
	and cash accounts:
			31-Oct-14			30-Apr-14
	Restricted		$	387,097		$	6,176,656
	Unrestricted			1,748,725			1,232,111
			$	2,135,822		$	7,408,767
Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]	'
	(h) Long-Lived Assets
	Long-lived assets, such as property and equipment and patents subject to amortization, are 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. During the six months ended October 31, 2014, the Company reviewed its long-lived assets for impairment and estimated that the remaining useful lives, for purposes of amortizing capitalized external patent costs, should be reduced from approximately five years to one year.
Concentration Risk, Credit Risk, Policy [Policy Text Block]	'
	(i) Concentration of Credit Risk
	Financial instruments that potentially subject the Company to concentration of credit risk consist principally of cash balances, bank certificates of deposit and trade receivables. The Company invests its excess cash in highly liquid investments (principally, short-term bank deposits, Treasury bills, Treasury notes and money market funds) and does not believe that it is exposed to any significant risks related to its cash accounts, money market funds or certificates of deposit.
	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:
			Three months ended October 31,						Six months ended October 31,
	Customer		2014			2013			2014			2013
	US Department of Energy			65	%		22	%		38	%		24	%
	Mitsui Engineering & Shipbuilding			35	%		15	%		33	%		8	%
	European Union (WavePort project)		?				61	%		29	%		46	%
	UK Government's Technology Strategy Board		?			?			?				19	%
				100	%		98	%		100	%		97	%
	The loss of, or a significant reduction in revenues from, any of the current customers could significantly impact the Company's financial position or results of operations. The Company does not require its customers to maintain collateral.
Earnings Per Share, Policy [Policy Text Block]	'
	(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 outstanding during the period. Due to the Company's net losses, potentially dilutive securities, consisting of outstanding stock options and non-vested performance-based shares, were excluded from the diluted loss per share calculation due to their anti-dilutive effect.
	In computing diluted net loss per share, options to purchase shares of common stock and non-vested restricted stock issued to employees and non-employee directors, totaling 1,649,813 for the three and six months ended October 31, 2014, and 1,493,353 for the three and six months ended October 31, 2013, were excluded from the computations as the effect would be anti-dilutive due to the Company's losses.
New Accounting Pronouncements, Policy [Policy Text Block]	'
	(k)
	Recently Issued Accounting Standards
	On May 28, 2014, the FASB issued ASU No. 2014-09,
	Revenue from Contracts with Customers
	, which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The ASU will replace most existing revenue recognition guidance in U.S. Generally Accepted Accounting Principles (“GAAP”) when it becomes effective. The new standard is effective for us on January 1, 2017. Early application is not permitted. The standard permits the use of either the retrospective or the cumulative effect transition method. We are evaluating the effect that ASU 2014-09 will have on our consolidated financial statements and related disclosures. We have not yet selected a transition method nor have we determined the effect of the standard on our ongoing financial reporting.
	In August 2014, the FASB issued ASU 2014-15,
	Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern
	, which describes how an entity should assess its ability to meet obligations and sets rules for how this information should be disclosed in the financial statements. The standard provides accounting guidance that will be used along with existing auditing standards. The new standard applies to all entities for the first annual period ending after December 15, 2016, and interim periods thereafter. Early application is permitted.  We are evaluating the effect ASU 2014-15 will have on our consolidated financial statements and disclosures and have not yet determined the effect of the standard on our ongoing financial reporting at this time.

Note_2_Summary_of_Significant_1

Note 2 - Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Oct. 31, 2014
Notes Tables	'
Schedule of Cash and Cash Equivalents [Table Text Block]	'
		31-Oct-14			30-Apr-14
	Checking and savings accounts	$	3,349,284		$	1,917,176
	Certificates of deposits and US Treasury obligations		847,039			11,499,768
	Money market funds		2,042,385			441,715
		$	6,238,708		$	13,858,659
Schedule of Restricted Cash and Cash Equivalents [Table Text Block]	'
		31-Oct-14			30-Apr-14
	Current:
	Australian Renewable Energy Agency (ARENA)	―			$	5,179,960
	NJBPU agreement		125,000			100,000
	Oregon Department of State Lands		22,000			845,000
	Barclay's Bank Agreement		387,097		―
		$	534,097		$	6,124,960
		31-Oct-14			30-Apr-14
	Long Term:
	Barclay's Bank Agreement	―			$	996,696
	NJBPU agreement		100,000			225,000
		$	100,000		$	1,221,696
Schedule of Foreign Exchange Gain Loss [Table Text Block]	'
		Three Months Ended October 31,						Six Months Ended October 31,
		2014			2013			2014			2013
	Foreign exchange (loss) gain	$	(216,249	)	$	107,357		$	(221,907	)	$	129,127
Schedule of Foreign Currency Denominated Certificates of Deposit and Cash Accounts	'
		31-Oct-14			30-Apr-14
	Restricted	$	387,097		$	6,176,656
	Unrestricted		1,748,725			1,232,111
		$	2,135,822		$	7,408,767
Schedule of Revenue by Major Customers by Reporting Segments [Table Text Block]	'
		Three months ended October 31,						Six months ended October 31,
	Customer	2014			2013			2014			2013
	US Department of Energy		65	%		22	%		38	%		24	%
	Mitsui Engineering & Shipbuilding		35	%		15	%		33	%		8	%
	European Union (WavePort project)	―				61	%		29	%		46	%
	UK Government's Technology Strategy Board	―			―			―				19	%
			100	%		98	%		100	%		97	%

Note_3_Marketable_Securities_T

Note 3 - Marketable Securities (Tables) (Current [Member])	6 Months Ended
	Oct. 31, 2014
Current [Member]	'
Notes Tables	'
Marketable Securities [Table Text Block]	'
		31-Oct-14		30-Apr-14
	US Treasury obligations	$	16,495,278	$	14,493,881

Note_4_Balance_Sheet_Detail_Ta

Note 4 - Balance Sheet Detail (Tables)	6 Months Ended
	Oct. 31, 2014
Notes Tables	'
Schedule of Other Assets and Other Liabilities [Table Text Block]	'
		31-Oct-14			30-Apr-14
	Accounts receivable, net
	Accounts receivable	$	―		$	308,731
	Allowance for doubtful accounts		―			―
		$	―		$	308,731
	Patents
	Patents	$	1,536,029		$	1,536,029
	Accumulated amortization		(1,121,878	)		(707,731	)
		$	414,151		$	828,298
	Accrued expenses
	Project costs	$	669,412		$	1,263,293
	Contract loss reserve		308,343			―
	Employee incentive payments		466,480			310,370
	Accrued salary and benefits		464,766			455,909
	Legal and accounting fees		739,454			168,402
	Goods and services tax (GST) due to Australian Tax Office		―			470,905
	Other		236,830			262,360
		$	2,885,285		$	2,931,239

Note_5_Related_Party_Transacti1

Note 5 - Related Party Transactions (Tables)	6 Months Ended
	Oct. 31, 2014
Notes Tables	'
Schedule of Related Party Transactions [Table Text Block]	'
		Three Months Ended October 31,
		2014		2013
	Related party consulting expense	$	151,875	$	―
		Six Months Ended October 31,
		2014		2013
	Related party consulting expense	$	265,688	$	―

Note_6_Debt_Tables

Note 6 - Debt (Tables)	6 Months Ended
	Oct. 31, 2014
Notes Tables	'
Schedule of Debt [Table Text Block]	'
		31-Oct-14			30-Apr-14
	Total debt	$	200,000		$	250,000
	Current portion of long-term debt		(100,000	)		(100,000	)
	Long-term debt	$	100,000		$	150,000

Note_8_StockBased_Compensation1

Note 8 - Stock-Based Compensation (Tables)	6 Months Ended
	Oct. 31, 2014
Notes Tables	'
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	'
		Six Months Ended October 31,
		2014			2013
	Risk-free interest rate		1.6	%		1.6	%
	Expected dividend yield		0	%		0	%
	Expected life (years)		5.5			6
	Expected volatility		85.49	%		74.61	%
Schedule of Share-based Compensation, Activity [Table Text Block]	'
								Weighted
								Average
					Weighted			Remaining
		Shares			Average			Contractual
		Underlying			Exercise			Term
		Options			Price			(In Years)
	Outstanding as of April 30, 2014		1,472,292		$	5.53			5.9
	Forfeited		(490,233	)		7.03
	Exercised		—			—
	Granted		115,913			1.02
	Outstanding as of October 31, 2014		1,097,972			4.39			6.2
	Exercisable as of October 31, 2014		750,390			5.79			4.9
Schedule of Share-based Compensation, Restricted Stock Units Award Activity [Table Text Block]	'
					Weighted
		Number			Average Price per
		of Shares			Share
	Issued and unvested at April 30, 2014		97,610		$	2.23
	Granted		270,513			1.03
	Forfeited		(9,380	)		2.3
	Vested		(50,901	)		2.13
	Issued and unvested at October 31, 2014		307,842			1.19

Note_11_Operating_Segments_and1

Note 11 - Operating Segments and Geographic Information (Tables)	6 Months Ended
	Oct. 31, 2014
Notes Tables	'
Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Table Text Block]	'
		North America			Europe			Asia and Australia			Total
	Three months ended October 31, 2014
	Revenues from external customers	$	1,747,788		$	—		$	—		$	1,747,788
	Operating loss		(3,614,964	)		(341,804	)		(226,885	)		(4,183,653	)
	Three months ended October 31, 2013
	Revenues from external customers		460,837			2,771			—			463,608
	Operating loss		(2,714,747	)		(396,523	)		(306,439	)		(3,417,709	)
	Six months ended October 31, 2014
	Revenues from external customers		3,288,316			—			—			3,288,316
	Operating loss		(6,197,577	)		(734,672	)		(720,957	)		(7,653,206	)
	Six months ended October 31, 2013
	Revenues from external customers		748,589			175,946			—			924,535
	Operating loss		(5,837,346	)		(711,925	)		(686,591	)		(7,235,862	)
	31-Oct-14
	Long-lived assets		259,210			6,676			—			265,886
	Total assets		23,192,939			909,092			677,816			24,779,847
	30-Apr-14
	Long-lived assets		305,314			12,024			175			317,513
	Total assets	$	31,313,240		$	1,003,205		$	5,768,390		$	38,084,835

Note_1_Background_Basis_of_Pre1

Note 1 - Background, Basis of Presentation and Liquidity (Details Textual) (USD $)	6 Months Ended			6 Months Ended	12 Months Ended
	Oct. 31, 2014	Oct. 31, 2013	Apr. 30, 2014	Oct. 31, 2014	Apr. 30, 2014	Apr. 30, 2014
				Proceeds from S-3 Shelf for Period [Member]	ATM Facility [Member]	Underwriting Agreement [Member]
Accounting Policies [Abstract]	'	'	'	'	'	'
Retained Earnings (Accumulated Deficit)	$159,292,949	'	$151,640,503	'	'	'
Cash Cash Equivalents and Marketable Securities	22,800,000	'	28,400,000	'	'	'
Stock Issued During Period, Shares, New Issues	'	'	'	'	3,306,334	3,800,000
Share Price	'	'	'	'	$3.02	$3.10
Proceeds from Issuance of Common Stock	1,155	3,429,799	'	0	9,698,000	10,828,000
Shelf Registration Authorized Amount	40,000,000	'	'	'	'	'
Shelf Registration Amount Remaining of Offering Amount	18,200,000	'	'	'	'	'
Restricted Cash and Cash Equivalents	$600,000	'	$7,300,000	'	'	'

Note_2_Summary_of_Significant_2

Note 2 - Summary of Significant Accounting Policies (Details Textual)

1 Months Ended

3 Months Ended

6 Months Ended

6 Months Ended

6 Months Ended

Aug. 31, 2014

Aug. 31, 2014

Oct. 31, 2014

Oct. 31, 2013

Oct. 31, 2014

Oct. 31, 2013

Apr. 30, 2014

Apr. 30, 2014

Apr. 30, 2014

Oct. 31, 2014

Oct. 31, 2014

Jul. 31, 2014

Jul. 31, 2014

Oct. 31, 2014

Oct. 31, 2014

Oct. 31, 2014

Oct. 31, 2014

Jul. 31, 2014

Oct. 31, 2014

Oct. 31, 2014

Oct. 31, 2014

USD ($)

AUD

USD ($)

USD ($)

USD ($)

Grant Funding [Member]

Grant Funding [Member]

Barclays Bank [Member]

Barclays Bank [Member]

Barclays Bank [Member]

Barclays Bank [Member]

New Jersey Board of Public Utilities [Member]

Foreign Tax Authority [Member]

Foreign Tax Authority [Member]

Letter of Credit [Member]

Letter of Credit [Member]

Victorian Wave Partners Pty. Ltd. [Member]

Intangible Assets, Amortization Period [Member]

Intangible Assets, Amortization Period [Member]

USD ($)

AUD

USD ($)

EUR (€)

USD ($)

EUR (€)

USD ($)

Australian Taxation Office [Member]

Australian Taxation Office [Member]

Oregon Department of State Lands [Member]

Oregon Department of State Lands [Member]

OPTA [Member]

Prior to Impairment Review [Member]

Revised Estimate [Member]

USD ($)

AUD

USD ($)

USD ($)

Accounting Policies [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

11.80%

'

'

Ownership Percentage

'

'

100.00%

'

100.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Line of Credit Facility, Commitment Fee Percentage

'

'

'

'

'

'

'

'

'

1.00%

1.00%

'

'

'

'

'

'

'

'

'

'

Line of Credit Facility, Maximum Borrowing Capacity

'

'

'

'

'

'

'

'

'

$387,097

€ 307,000

$964,656

€ 800,000

$500,000

'

'

$22,000

$1,200,000

'

'

'

Long-term Line of Credit

'

'

'

'

'

'

'

'

'

351,655

278,892

'

'

200,000

'

'

'

'

'

'

'

Restricted Cash and Cash Equivalents

'

'

600,000

'

600,000

'

7,300,000

5,179,960

5,595,723

'

'

'

'

'

'

'

'

'

'

'

'

Goods and Services Tax Due to Foreign Office

'

'

'

'

'

'

470,905

'

'

'

'

'

'

'

470,905

508,702

'

'

'

'

'

Repayments of Grant Funding

5,179,960

5,595,723

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Interest Paid

$102,061

109,051

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Finite-Lived Intangible Asset, Useful Life

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'5 years

'1 year

Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount

'

'

1,649,813

1,493,353

1,649,813

1,493,353

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Note_2_Summary_of_Significant_3

Note 2 - Summary of Significant Accounting Policies - Cash and Cash Equivalents (Details) (USD $)	Oct. 31, 2014	Apr. 30, 2014
Cash and cash equivalents	$6,238,708	$13,858,659
Money Market Funds [Member]	'	'
Cash and cash equivalents	2,042,385	441,715
Certificates of Deposits and US Treasury Obligations [Member]	'	'
Cash and cash equivalents	847,039	11,499,768
Checking and Savings Accounts [Member]	'	'
Cash and cash equivalents	$3,349,284	$1,917,176

Note_2_Summary_of_Significant_4

Note 2 - Summary of Significant Accounting Policies - Cash Restricted Under Security Agreements (Details) (USD $)	Oct. 31, 2014	Apr. 30, 2014
Current:	'	'
Australian Renewable Energy Agency (ARENA)	$534,097	$6,124,960
Long Term:	'	'
Barclay's Bank Agreement	100,000	1,221,696
Australian Renewable Energy Agency [Member]	'	'
Current:	'	'
Australian Renewable Energy Agency (ARENA)	'	5,179,960
Barclays Bank Agreement [Member]	'	'
Current:	'	'
Australian Renewable Energy Agency (ARENA)	387,097	'
Long Term:	'	'
Barclay's Bank Agreement	'	996,696
NJBPU Agreement [Member]	'	'
Current:	'	'
Australian Renewable Energy Agency (ARENA)	125,000	100,000
Long Term:	'	'
Barclay's Bank Agreement	100,000	225,000
Oregon Department of State Lands [Member]	'	'
Current:	'	'
Australian Renewable Energy Agency (ARENA)	$22,000	$845,000

Note_2_Summary_of_Significant_5

Note 2 - Summary of Significant Accounting Policies - Foreign Exchange Gain (Loss) (Details) (USD $)	3 Months Ended		6 Months Ended
	Oct. 31, 2014	Oct. 31, 2013	Oct. 31, 2014	Oct. 31, 2013
Foreign exchange (loss) gain	($216,249)	$107,357	($221,907)	$129,127

Note_2_Summary_of_Significant_6

Note 2 - Summary of Significant Accounting Policies - Foreign Currency Denominated Certificates of Deposit and Cash Accounts (Details) (USD $)	Oct. 31, 2014	Apr. 30, 2014
Restricted	$2,135,822	$7,408,767
Restricted [Member]	'	'
Restricted	387,097	6,176,656
Unrestricted [Member]	'	'
Restricted	$1,748,725	$1,232,111

Note_2_Summary_of_Significant_7

Note 2 - Summary of Significant Accounting Policies - Revenues by Major Customers (Details)	3 Months Ended		6 Months Ended
	Oct. 31, 2014	Oct. 31, 2013	Oct. 31, 2014	Oct. 31, 2013
US Department of Energy	100.00%	98.00%	100.00%	97.00%
European Union Waver Port Project [Member]	'	'	'	'
US Department of Energy	65.00%	22.00%	38.00%	24.00%
Mitsui Engineering and Ship Building [Member]	'	'	'	'
US Department of Energy	35.00%	15.00%	33.00%	8.00%
UK Governments Technology Strategy Board [Member]	'	'	'	'
US Department of Energy	'	'	'	19.00%
US Department of Energy [Member]	'	'	'	'
US Department of Energy	'	61.00%	29.00%	46.00%

Note_3_Marketable_Securities_M

Note 3 - Marketable Securities - Marketable Securities That Mature Within One Year (Details) (USD $)	Oct. 31, 2014	Apr. 30, 2014
US Treasury obligations	$16,495,278	$14,493,881
US Treasury Obligations [Member]	'	'
US Treasury obligations	$16,495,278	$14,493,881

Note_4_Balance_Sheet_Detail_Ba

Note 4 - Balance Sheet Detail - Balance Sheet Details (Details) (USD $)	Oct. 31, 2014	Apr. 30, 2014
Accounts receivable, net	'	'
Accounts receivable	'	$308,731
Total	'	308,731
Patents	'	'
Patents	1,536,029	1,536,029
Accumulated amortization	-1,121,878	-707,731
Total	414,151	828,298
Accrued expenses	'	'
Project costs	669,412	1,263,293
Contract loss reserve	308,343	'
Employee incentive payments	466,480	310,370
Accrued salary and benefits	464,766	455,909
Legal and accounting fees	739,454	168,402
Goods and services tax (GST) due to Australian Tax Office	'	470,905
Other	236,830	262,360
Total	$2,885,285	$2,931,239

Note_5_Related_Party_Transacti2

Note 5 - Related Party Transactions (Details Textual) (USD $)	1 Months Ended		3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended
	Apr. 30, 2014	Jun. 30, 2014	Oct. 31, 2014	Oct. 31, 2014	Oct. 31, 2014	Oct. 31, 2014
	Former Executive Vice Chairman [Member]	Interim Chief Executive Officer [Member]	Consulting Fees [Member]	Consulting Fees [Member]	Consulting Fees [Member]	Consulting Fees [Member]
			Former Executive Vice Chairman [Member]	Former Executive Vice Chairman [Member]	Interim Chief Executive Officer [Member]	Interim Chief Executive Officer [Member]
Related Party Transactions [Abstract]	'	'	'	'	'	'
Related Party Transaction Monthly Consulting Fee	$20,000	'	'	'	'	'
Related Party Transaction, Expenses from Transactions with Related Party	'	'	60,000	120,000	91,875	145,688
Related Party Transaction Daily Consulting Fee	'	$1,500	'	'	'	'

Note_5_Related_Party_Transacti3

Note 5 - Related Party Transactions - Related Party Transactions (Details) (USD $)	3 Months Ended	6 Months Ended
	Oct. 31, 2014	Oct. 31, 2014
Related party consulting expense	$151,875	$265,688

Note_6_Debt_Details_Textual

Note 6 - Debt (Details Textual) (USD $)	Oct. 31, 2014	Apr. 30, 2014	Nov. 30, 2011
			New Jersey Board of Public Utilities 1 [Member]
Debt Disclosure [Abstract]	'	'	'
Long-term Debt	$200,000	$250,000	$500,000
Long-term Debt Payment Terms	'	'	'5 years

Note_6_Debt_Longterm_Debt_Deta

Note 6 - Debt - Long-term Debt (Details) (USD $)	Oct. 31, 2014	Apr. 30, 2014
Long-term Debt	$200,000	$250,000
Current portion of long-term debt	-100,000	-100,000
Long-term debt	$100,000	$150,000

Note_7_Deferred_Credits_Payabl1

Note 7 - Deferred Credits Payable (Details Textual) (USD $)	Oct. 31, 2014	Jul. 31, 2014	Apr. 30, 2014	Apr. 30, 2001
				T
				Rate
Increase (Decrease) in Customer Advances and Deposits [Abstract]	'	'	'	'
Customer Advances and Deposits	'	'	'	$600,000
Deferred Credits Payable Option Details	'	'	'	500,000
Deferred Credits Payable Market Discount Rate	'	'	'	30.00%
Deferred Credits Payable Market Liquidated Damages Rate	'	'	'	30.00%
Customer Advances or Deposits, Noncurrent	$600,000	$600,000	$600,000	'

Note_8_StockBased_Compensation2

Note 8 - Stock-Based Compensation (Details Textual) (USD $)	6 Months Ended
	Oct. 31, 2014	Oct. 31, 2013	Apr. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'	'	'
Allocated Share-based Compensation Expense	$153,000	$370,000	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$0.72	$1.11	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	0	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number	343,000	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term	'8 years 328 days	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	1,097,972	'	1,472,292
Treasury Stock, Shares, Acquired	806	4,081	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value	0	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value	0	'	'
Performance based vesting [Member]	'	'	'
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	115,786	'	'
Including Non-employee Compensation [Member]	'	'	'
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'	'	'
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options	250,000	'	'
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	'2 years 73 days	'	'
Employee Stock Option [Member]	'	'	'
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'	'	'
Allocated Share-based Compensation Expense	75,000	348,000	'
Restricted Stock [Member]	'	'	'
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'	'	'
Allocated Share-based Compensation Expense	78,000	21,000	'
Restricted Stock [Member] | Performance based vesting [Member]	'	'	'
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	243,999	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	37,329	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Forfeitures	9,380	'	'
Restricted Stock [Member] | Service-based Vesting [Member]	'	'	'
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	270,513	'	'
Restricted Stock [Member] | Including Non-employee Compensation [Member]	'	'	'
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'	'	'
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	'3 years 36 days	'	'
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$245,000	'	'

Note_8_StockBased_Compensation3

Note 8 - Stock-Based Compensation - Weighted Average Fair Value Assumptions for Stock-Based Compensation (Details)	6 Months Ended
	Oct. 31, 2014	Oct. 31, 2013
	Rate	Rate
Risk-free interest rate	1.60%	1.60%
Expected dividend yield	0.00%	0.00%
Expected life (years)	'5 years 182 days	'6 years
Expected volatility	85.49%	74.61%

Note_8_StockBased_Compensation4

Note 8 - Stock-Based Compensation - Stock Options Under the Plans (Details) (USD $)	6 Months Ended	12 Months Ended
	Oct. 31, 2014	Apr. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	1,097,972	1,472,292
Outstanding as of April 30, 2014 (in dollars per share)	$4.39	$5.53
Outstanding as of April 30, 2014	'6 years 73 days	'5 years 328 days
Forfeited (in shares)	-490,233	'
Forfeited (in dollars per share)	$7.03	'
Granted (in shares)	115,913	'
Exercisable as of October 31, 2014 (in shares)	750,390	'
Exercisable as of October 31, 2014 (in dollars per share)	$5.79	'
Exercisable as of October 31, 2014	'4 years 328 days	'

Note_8_StockBased_Compensation5

Note 8 - Stock-Based Compensation - Non-vested Restricted Stock Under the Plans (Details) (Non-vested Restricted Stock [Member], USD $)	6 Months Ended
	Oct. 31, 2014	Apr. 30, 2014
Non-vested Restricted Stock [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	307,842	97,610
Issued and unvested at April 30, 2014 (in dollars per share)	$1.19	$2.23
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	270,513	'
Granted (in dollars per share)	$1.03	'
Forfeited (in shares)	-9,380	'
Forfeited (in dollars per share)	$2.30	'
Vested (in shares)	-50,901	'
Vested (in dollars per share)	$2.13	'

Note_9_Commitments_and_Conting1

Note 9 - Commitments and Contingencies (Details Textual)	Oct. 31, 2014	Oct. 31, 2014	Oct. 31, 2014
	USD ($)	EUR (€)	Spanish Tax Authorities [Member]
			USD ($)
Commitments and Contingencies Disclosure [Abstract]	'	'	'
Input Tax	'	'	$250,000
Letters of Credit Outstanding, Amount	$373,574	€ 278,828	'

Note_10_Income_Taxes_Details_T

Note 10 - Income Taxes (Details Textual) (USD $)	6 Months Ended
	Oct. 31, 2014	Oct. 31, 2013
Income Tax Disclosure [Abstract]	'	'
Income Tax Expense (Benefit)	$0	$0

Note_11_Operating_Segments_and2

Note 11 - Operating Segments and Geographic Information (Details Textual)	6 Months Ended
	Oct. 31, 2014
Segment Reporting [Abstract]	'
Number of Operating Segments	1
AUSTRALIA	'
Segment Reporting [Abstract]	'
Number of Reportable Segments	1
UNITED KINGDOM	'
Segment Reporting [Abstract]	'
Number of Reportable Segments	1
UNITED STATES	'
Segment Reporting [Abstract]	'
Number of Reportable Segments	1

Note_11_Operating_Segments_and3

Note 11 - Operating Segments and Geographic Information - Geographic Segment Information (Details) (USD $)	3 Months Ended		6 Months Ended
	Oct. 31, 2014	Oct. 31, 2013	Oct. 31, 2014	Oct. 31, 2013	Apr. 30, 2014
Revenues	$1,747,788	$463,608	$3,288,316	$924,535	'
Operating loss	-4,183,653	-3,417,709	-7,653,206	-7,235,862	'
Long-lived assets	265,886	'	265,886	'	317,513
Total assets	24,779,847	'	24,779,847	'	38,084,835
Europe [Member]	'	'	'	'	'
Revenues	'	2,771	'	175,946	'
Operating loss	-341,804	-396,523	-734,672	-711,925	'
Long-lived assets	6,676	'	6,676	'	12,024
Total assets	909,092	'	909,092	'	1,003,205
North America [Member]	'	'	'	'	'
Revenues	1,747,788	460,837	3,288,316	748,589	'
Operating loss	-3,614,964	-2,714,747	-6,197,577	-5,837,346	'
Long-lived assets	259,210	'	259,210	'	305,314
Total assets	23,192,939	'	23,192,939	'	31,313,240
Asia and Australia [Member]	'	'	'	'	'
Operating loss	-226,885	-306,439	-720,957	-686,591	'
Long-lived assets	'	'	'	'	175
Total assets	$677,816	'	$677,816	'	$5,768,390