Odyssey Marine Exploration (OMEX) 10-K 1 Apr 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Mar. 08, 2019	Jun. 30, 2018
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Trading Symbol	OMEX
Entity Registrant Name	ODYSSEY MARINE EXPLORATION INC
Entity Central Index Key	0000798528
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		9,222,199
Entity Public Float			$ 65.3

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Dec. 31, 2018	Dec. 31, 2017
CURRENT ASSETS
Cash and cash equivalents	$ 2,786,832	$ 1,108,193
Restricted cash	10,135	10,010
Accounts receivable and other, net	789,421	232,380
Other current assets	1,016,136	495,527
Total current assets	4,602,524	1,846,110
PROPERTY AND EQUIPMENT
Equipment and office fixtures	11,033,536	16,738,898
Accumulated depreciation	(10,915,557)	(16,145,082)
Total property and equipment	117,979	593,816
NON-CURRENT ASSETS
Investment in unconsolidated entity	752,667
Other non-current assets		532,500
Total non-current assets	752,667	532,500
Total assets	5,473,170	2,972,426
CURRENT LIABILITIES
Accounts payable	2,772,423	2,396,835
Accrued expenses	9,804,546	6,551,335
Loans payable	29,448,988	24,363,442
Total current liabilities	42,025,957	33,311,612
LONG-TERM LIABILITIES
Loans payable		3,000,000
Deferred income and revenue participation rights	4,643,750	4,643,750
Total long-term liabilities	4,643,750	7,643,750
Total liabilities	46,669,707	40,955,362
Commitments and contingencies (NOTE O)
STOCKHOLDERS' EQUITY/(DEFICIT)
Preferred stock - $.0001 par value; 24,984,166 shares authorized; none outstanding	0	0
Common stock - $.0001 par value; 75,000,000 shares authorized; 9,222,199 and 8,466,909 issued and outstanding	922	847
Additional paid-in capital	217,993,953	212,103,344
Accumulated (deficit)	(239,882,346)	(234,709,910)
Total stockholders' equity/(deficit) before non-controlling interest	(21,887,471)	(22,605,719)
Non-controlling interest	(19,309,066)	(15,377,217)
Total stockholders' equity/(deficit)	(41,196,537)	(37,982,936)
Total liabilities and stockholders' equity/(deficit)	$ 5,473,170	$ 2,972,426

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	24,984,166	24,984,166
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	75,000,000	75,000,000
Common stock, shares issued	9,222,199	9,222,199
Common stock, shares outstanding	8,466,909	8,466,909

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
REVENUE
Revenue	$ 3,275,753	$ 1,248,477	$ 4,683,035
OPERATING EXPENSES
Operations and research	3,688,560	3,438,389	8,267,401
Gain on sale of marine assets			(992,595)
Marketing, general and administrative	5,654,409	6,167,181	7,959,122
Total operating expenses	9,342,969	9,605,570	15,233,928
LOSS FROM OPERATIONS	(6,067,216)	(8,357,093)	(10,550,893)
OTHER INCOME OR (EXPENSE)
Interest income	56,408	112
Interest expense	(3,142,280)	(2,727,235)	(2,396,994)
Change in derivative liabilities fair value			3,402,416
Other	48,803	63,074	467,396
Total other income or (expense)	(3,037,069)	(2,664,049)	1,472,818
LOSS BEFORE INCOME TAXES	(9,104,285)	(11,021,142)	(9,078,075)
Income tax benefit (provision)	0	0	0
NET (LOSS) BEFORE NON-CONTROLLING INTEREST	(9,104,285)	(11,021,142)	(9,078,075)
Non-controlling interest	3,931,849	3,261,670	2,762,054
NET (LOSS)	$ (5,172,436)	$ (7,759,472)	$ (6,316,021)
LOSS PER SHARE
Basic and diluted	$ (0.60)	$ (0.95)	$ (0.84)
Weighted average number of common shares outstanding
Basic and diluted	8,583,795	8,209,539	7,564,082
Cargo and Other [Member]
REVENUE
Revenue	$ 835,756	$ 11,854	$ 7,057
Expedition [Member]
REVENUE
Revenue	$ 2,439,997	$ 1,236,623	$ 4,675,978

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity / (Deficit) - USD ($)	Total	Preferred Stock [Member]	Common Stock [Member]	Paid-in Capital [Member]	Accumulated Deficit [Member]	Non-controlling Interest [Member]
Beginning Balance, Shares at Dec. 31, 2015			7,541,111
Preferred stock converted to common, Share		0
Common stock issued for services, shares			177,255
Ending Balance, Shares at Dec. 31, 2016			7,718,366
Beginning Balance at Dec. 31, 2015			$ 754	$ 204,438,148	$ (220,634,417)	$ (9,353,493)
Preferred stock converted to common		$ 0
Net (loss)	$ (6,316,021)				(6,316,021)	(2,762,054)
Common stock issued for services			18	354,155
Share-based compensation				1,662,969
Fair value of warrants attached convertible debt				303,712
Beneficial conversion feature on convertible debt				630,519
Net gain on debt extinguishment				572,843
Ending Balance at Dec. 31, 2016	(31,102,867)		$ 772	207,962,346	(226,950,438)	(12,115,547)
Preferred stock converted to common, Share		0
Common stock issued for settlement of senior convertible notes, Shares			670,455
Common stock issued for services, shares			78,088
Ending Balance, Shares at Dec. 31, 2017			8,466,909
Preferred stock converted to common		$ 0
Net (loss)	(7,759,472)				(7,759,472)	(3,261,670)
Common stock issued for settlement of senior convertible notes			$ 67	3,352,207
Common stock issued for services			8
Share-based compensation				725,866
Beneficial conversion feature on convertible debt				62,925
Ending Balance at Dec. 31, 2017	(37,982,936)		$ 847	212,103,344	(234,709,910)	(15,377,217)
Common stock issued for cash			700,000
Preferred stock converted to common, Share		0
Common stock issued for services, shares			55,290
Ending Balance, Shares at Dec. 31, 2018			9,222,199
Common stock issued for cash			$ 70
Preferred stock converted to common		$ 0
Net (loss)	(5,172,436)				(5,172,436)	(3,931,849)
Common stock issued for services			5
Share-based compensation				278,941
Fair value of warrants attached convertible debt				303,812
Beneficial conversion feature on convertible debt				746,187
Common stock issued for cash, net				4,561,669
Ending Balance at Dec. 31, 2018	$ (41,196,537)		$ 922	$ 217,993,953	$ (239,882,346)	$ (19,309,066)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net (loss) before non-controlling interest	$ (9,104,285)	$ (11,021,142)	$ (9,078,075)
Adjustments to reconcile net loss to net cash (used) in operating activities:
Note payable interest accretion	111,180	384,060	272,826
Senior convertible debt interest settled with common stock issuance		302,274
Share-based compensation	278,947	725,875	1,662,978
Depreciation and amortization	453,466	760,766	1,063,267
Accounts receivable-reserve			29,932
Director fees settled with equity instruments			176,664
Fair value of warrants attached to convertible debt			303,712
Change in derivatives liabilities fair value			(3,402,416)
Financed lender fees		50,000	50,000
Investment in unconsolidated entity	(752,667)
Gain on sale of equipment	(897,664)	(289,328)	(992,595)
Deferred revenue			(383,148)
(Increase) decrease in:
Accounts receivable	(578,156)	241,426	297,837
Other assets	11,891	113,922	(204,380)
Increase (decrease) in:
Accounts payable	496,068	999,488	(329,864)
Accrued expenses and other	3,528,805	1,881,977	2,228,070
NET CASH (USED) IN OPERATING ACTIVITIES	(6,452,415)	(5,850,682)	(8,305,192)
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from sale of equipment	1,003,662	80,000	200,000
Purchase of property and equipment	(9,624)		(129,684)
NET CASH PROVIDED BY INVESTING ACTIVITIES	994,038	80,000	70,316
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of loan payable	1,925,000	5,625,000	7,825,000
Restricted cash held as collateral	(125)		(10,000)
Settlement receipts from contractual obligation	15,000,000
Payment of contractual obligation	(14,000,000)
Proceeds from sale of common stock	4,561,739
Repayment of loan and debt obligations	(349,598)	(408,768)	(158,798)
NET CASH PROVIDED BY FINANCING ACTIVITIES	7,137,016	5,216,232	7,656,202
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	1,678,639	(554,450)	(578,674)
CASH AND CASH EQUIVALENTS AT BEGINNING OF YEAR	1,108,193	1,662,643	2,241,317
CASH AND CASH EQUIVALENTS AT END OF YEAR	2,786,832	1,108,193	1,662,643
SUPPLEMENTARY INFORMATION:
Interest paid	1,247,337	622,055	893,502
Income taxes paid	$ 0	$ 0	0
NON-CASH TRANSACTIONS:
Accrued and director fees compensation paid by equity instruments			177,500
Accounts payables settled as non-cash consideration for the sale of equipment			890,598
Asset received as non-cashconsideration for the sale of other property and equipment			$ 350,000

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows (Parenthetical) - USD ($)	1 Months Ended	3 Months Ended
	Apr. 30, 2018	Jun. 30, 2017
Marine Vessel [Member]
Cash proceeds from sale of vessel		$ 650,000
Monaco [Member]
Back rent considered as part of loan	$ 99,366
Note 2 [Member]
Loans payable, repayment		650,000
Epsilon Acquisitions, LLC [Member] | Notes Payable, Other Payables [Member]
Converted instrument, amount		3,050,000
Accrued interest		$ 302,274
Conversion of stock, shares Issued		670,455

Organization and Summary of Sig

Organization and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Summary of Significant Accounting Policies	NOTE A – ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Organization Odyssey Marine Exploration, Inc. and subsidiaries (the “Company,” “Odyssey,” “us,” “we” or “our”) is engaged in deep-ocean exploration. Our innovative techniques are currently applied to mineral exploration, shipwreck cargo recovery, and other marine survey and exploration charter services. Our corporate headquarters are located in Tampa, Florida. Summary of Significant Accounting Policies This summary of significant accounting policies of the Company is presented to assist in understanding our financial statements. The financial statements and notes are representations of the Company’s management who are responsible for their integrity and objectivity and have prepared them in accordance with our customary accounting practices. Recent accounting pronouncements In May 2014, the Financial Accounting Standards Board, or the FASB, issued Accounting Standards Update 2014-09, Revenue from Contracts with Customers 2014-09, In February 2016, the FASB issued Accounting Standards Update (ASU) 2016-02, Leases In May 2017, the FASB issued ASU 2017-09, Compensation-Stock Compensation (Topic 718), Scope of Modification Accounting. In July 2017, the FASB issued Accounting Standards Update No. 2017-11, Earnings Per Share (Topic 260), Distinguishing Liabilities from Equity (Topic 480), Derivatives and Hedging (Topic 815). 470-20, In March 2018, the FASB issued ASU No. 2018-05, Income Taxes Other recent accounting pronouncements issued by the FASB, the AICPA and the SEC did not or are not believed by management to have a material effect, if any, on the Company’s financial statements. Principles of Consolidation The consolidated financial statements include the accounts of the Company and its direct and indirect wholly owned subsidiaries, both domestic and international. Equity investments in which we exercise significant influence but do not control and of which we are not the primary beneficiary are accounted for using the equity method. All significant inter-company and intra-company transactions and balances have been eliminated. The results of operations attributable to the non-controlling non-wholly Use of Estimates Management uses estimates and assumptions in preparing these consolidated financial statements in accordance with U.S. GAAP. Those estimates and assumptions affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities, and the reported revenues and expenses. Actual results could vary from the estimates that were used. Revenue Recognition and Accounts Receivable In accordance with Topic A.1. in SAB 13 as well as ASU 2019-09, Account receivables are based on amounts billed to customers. Management has elected to record bad debts using the direct write-off write-off Cash and Cash Equivalents Cash, cash equivalents and restricted cash include cash on hand and cash in banks. We also consider all highly liquid investments with a maturity of three months or less when purchased to be cash equivalents. We have $10,135 of restricted cash for collateral related to a corporate credit card program. Long-Lived Assets Our policy is to recognize impairment losses relating to long-lived assets in accordance with the Accounting Standards Codification (“ASC”) topic for Property, Plant and Equipment. Decisions are based on several factors, including, but not limited to, management’s plans for future operations, recent operating results and projected cash flows. Impairment losses are included in depreciation at the time of impairment. Property and Equipment and Depreciation Property and equipment is stated at historical cost. Depreciation is calculated using the straight-line method at rates based on the assets’ estimated useful lives which are normally between three and thirty years. Leasehold improvements are amortized over their estimated useful lives or lease term, if shorter. Items that may require major overhauls (such as engines or generators) that enhance or extend the useful life of vessel related assets qualify to be capitalized and depreciated over the useful life or remaining life of that asset, whichever was shorter. Certain major repair items required by industry standards to ensure a vessel’s seaworthiness also qualified to be capitalized and depreciated over the period of time until the next scheduled planned major maintenance for that item. All other repairs and maintenance were accounted for under the direct-expensing method and are expensed when incurred. The smaller vessel we received as consideration when we sold our Odyssey Explorer Earnings Per Share Basic earnings per share (“EPS”) is computed by dividing income available to common stockholders by the weighted-average number of common shares outstanding for the period. In periods when the Company has income, the Company would calculate basic earnings per share using the two-class Earnings Per Share. two-class two-class two-class Diluted EPS reflects the potential dilution that would occur if dilutive securities and other contracts to issue common stock were exercised or converted into common stock or resulted in the issuance of common stock that then shared in our earnings. We use the treasury stock method to compute potential common shares from stock options and warrants and the if-converted if-converted two-class At December 31, 2018, 2017 and 2016 the weighted average common shares outstanding were 8,583,795, 8,209,539 and 7,564,082, respectively. For the periods ending December 31, 2018, 2017 and 2016 in which net losses occurred, all potential common shares were excluded from Diluted EPS because the effect of including such shares would be anti-dilutive. The potential common shares, in the table following, represent potential common shares calculated using the treasury stock method from outstanding options and warrants that were excluded from the calculation of Diluted EPS: 2018 2017 2016 Average market price during the period $ 6.81 $ 3.98 $ 3.46 In the money potential common shares from options excluded 13,450 7,023 4,979 In the money potential common shares from warrants excluded 50,640 13,869 — Potential common shares from out-of-the-money Per share exercise price 2018 2017 2016 Out of the money options excluded: $ 3.59 — — 7,521 $12.48 136,833 137,666 137,666 $12.84 4,167 4,167 4,167 $26.40 75,158 75,158 75,158 $34.68 — — 73,765 $39.00 — 8,333 8,333 $41.16 — — 833 $42.00 — — 8,333 $46.80 — — 1,667 Out-of-the-money $ 3.52 — — 120,000 $ 7.16 700,000 — — $12.00 60,625 — — Total excluded 981,783 225,324 437,443 Potential common shares from outstanding Convertible Preferred Stock calculated per the if-converted 2018 2017 2016 Excluded Convertible Preferred Stock — — — The weighted average equivalent common shares relating to our unvested restricted stock awards that were excluded from potential common shares used in the earning per share calculation due to having an anti-dilutive effect are: 2018 2017 2016 Excluded unvested restricted stock awards 41,667 132,826 113,889 The following is a reconciliation of the numerators and denominators used in computing basic and diluted net income per share: 12 Month 12 Month 12 Month Net loss $ (5,172,436 ) $ (7,759,472 ) $ (6,316,021 ) Cumulative dividends on Series G Preferred Stock — — — Numerator, basic and diluted net loss available to stockholders $ (5,172,436 ) $ (7,759,472 ) $ (6,316,021 ) 12 Month 12 Month 12 Month Denominator: Shares used in computation – basic: Weighted average common shares outstanding 8,583,795 8,209,539 7,564,082 Shares used in computation – diluted: Weighted average common shares outstanding 8,583,795 8,209,539 7,564,082 Net loss per share – basic and diluted $ (0.60 ) $ (0.95 ) $ (0.84 ) Income Taxes Income taxes are accounted for using an asset and liability approach that requires the recognition of deferred tax assets and liabilities for the expected future tax consequences attributable to differences between financial statement carrying amounts of existing assets and liabilities and their respective tax bases. A valuation allowance is provided when it is more likely than not that some portion or the entire deferred tax asset will not be realized. Stock-based Compensation Our stock-based compensation is recorded in accordance with the guidance in the ASC topic for Stock-Based Compensation Fair Value of Financial Instruments Financial instruments consist of cash, evidence of ownership in an entity, and contracts that both (i) impose on one entity a contractual obligation to deliver cash or another financial instrument to a second entity, or to exchange other financial instruments on potentially unfavorable terms with the second entity, and (ii) conveys to that second entity a contractual right (a) to receive cash or another financial instrument from the first entity, or (b) to exchange other financial instruments on potentially favorable terms with the first entity. Accordingly, our financial instruments consist of cash and cash equivalents, accounts receivable, accounts payable, accrued liabilities, derivative financial instruments and mortgage and loans payable. We carry cash and cash equivalents, accounts payable and accrued liabilities, and mortgage and loans payable at the approximate fair market value, and, accordingly, these estimates are not necessarily indicative of the amounts that we could realize in a current market exchange. We carry derivative financial instruments at fair value as is required under current accounting standards. Redeemable preferred stock has been carried at historical cost and accreted carrying values to estimated redemption values over the term of the financial instrument. Derivative financial instruments consist of financial instruments or other contracts that contain a notional amount and one or more underlying variables (e.g., interest rate, security price or other variable), require no initial net investment and permit net settlement. Derivative financial instruments may be free-standing or embedded in other financial instruments. Further, derivative financial instruments are initially, and subsequently, measured at fair value and recorded as liabilities or, in rare instances, assets. We generally do not use derivative financial instruments to hedge exposures to cash-flow, market or foreign-currency risks. However, we have entered into certain other financial instruments and contracts with features that are either (i) not afforded equity classification, (ii) embody risks not clearly and closely related to host contracts, or (iii) may be net-cash Derivatives and Hedging Fair Value Hierarchy The three levels of inputs that may be used to measure fair value are as follows: Level 1. Level 2. non-binding Level 3. non-binding non-binding Redeemable Preferred Stock If we issue redeemable preferred stock instruments (or any other redeemable financial instrument), they are initially evaluated for possible classification as a liability in instances where redemption is certain to occur pursuant to ASC 480 – Distinguishing Liabilities from Equity Subsequent Events We have evaluated subsequent events for recognition or disclosure through the date this Form 10-K

Concentration of Credit Risk

Concentration of Credit Risk	12 Months Ended
	Dec. 31, 2018
Risks and Uncertainties [Abstract]
Concentration of Credit Risk	NOTE B – CONCENTRATION OF CREDIT RISK We maintain the majority of our cash at one financial institution. At December 31, 2018 and 2017, our uninsured cash balance was approximately $2.6 million and $0.8 million, respectively. We do not have any outstanding loans that bear variable interest rates thus we do not have any corresponding interest rate risk.

Accounts Receivable and Other,

Accounts Receivable and Other, Net	12 Months Ended
	Dec. 31, 2018
Receivables [Abstract]
Accounts Receivable and Other, Net	NOTE C – ACCOUNTS RECEIVABLE AND OTHER, NET Our accounts receivable consisted of the following: December 31, 2018 December 31, 2017 Trade $ 9,466 $ 7,376 Related party 664,596 183,453 Other 115,359 41,551 Accounts receivable, net $ 789,421 $ 232,380 Monaco and its related affiliates owe us $612,498 and $183,453 for the periods ended December 31, 2018 and 2017, respectively, for support services and marine services rendered on their behalf. See NOTE J for further information regarding Monaco. During the quarter ended September 30, 2018, we began providing services for a deep-sea

Other Current Assets

Other Current Assets	12 Months Ended
	Dec. 31, 2018
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Current Assets	NOTE D – OTHER CURRENT ASSETS Our other current assets consist of the following: December 31, December 31, Prepaid expenses $ 478,560 $ 471,686 Project deposit 532,500 — Deposits 5,076 23,841 Total other current assets $ 1,016,136 $ 495,527 For the period ended December 31, 2018, prepaid expenses consisted of $388,137 for directors and officer’s insurance, $40,119 for marine insurance, $38,674 of professional services and $11,630 of other insurances. The Project deposit pertains to the HMS Sussex

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Property and Equipment	NOTE E – PROPERTY AND EQUIPMENT Property and equipment consist of the following: December 31, December 31, Computers and peripherals 1,021,844 1,278,461 Furniture and office equipment 1,907,116 2,625,028 Marine equipment 8,104,576 12,835,409 11,033,536 16,738,898 Less: Accumulated depreciation (10,915,557 ) (16,145,082 ) Property and equipment, net $ 117,979 $ 593,816 During 2018, we sold marine assets with an approximate gross cost of $4.6 million and an approximate net book value of $0.1 million to a Monaco related company for $1.0 million cash and assumed debt. During 2017, we sold this marine vessel to a related party, Monaco Financial, LLC, for $650,000. The consideration for this vessel was applied against our loan balance to Monaco in the amount of $650,000, see NOTE H. During 2016, we sold marine operational assets for a gain of $992,595 of which $792,595 is non-cash. non-cash in-kind

Other Non-Current Assets

Other Non-Current Assets	12 Months Ended
	Dec. 31, 2018
Investments, All Other Investments [Abstract]
Other Non-Current Assets	NOTE F – OTHER NON-CURRENT Other long-term assets consist of the following: December 31, December 31, Deposits $ — $ 532,500 Total other long-term assets $ — $ 532,500 Deposits for the year ended December 31, 2017 include $432,500 on account with the United Kingdom’s Ministry of Defense relating to the expense deposits for HMS Sussex Sussex

Investment In Unconsolidated En

Investment In Unconsolidated Entity	12 Months Ended
	Dec. 31, 2018
Equity Method Investments and Joint Ventures [Abstract]
Investment In Unconsolidated Entity	NOTE G – INVESTMENT IN UNCONSOLIDATED ENTITY Neptune Minerals, Inc. (NMI) Our current investment in NMI consists of 3,092,488 Class B Common non-voting non-voting non-voting Although we are a shareholder of NMI, we have no representation on the board of directors or in management of NMI and do not hold any Class A voting shares. We are not involved in the management of NMI nor do we participate in their policy-making. Accordingly, we are not the primary beneficiary of NMI. As of December 31, 2018, the net carrying value of our investment in NMI was zero in our consolidated financial statements. Chatham Rock Phosphate, Limited. During 2012, we performed deep-sea Debt and Equity Securities CIC, LLC In 2018, we entered into a transaction with a company controlled by Greg Stemm, the Chairman of the Board for Odyssey (See NOTE J for related parties). This company is pursuing deep water mining permits in foreign waters. Due to the initial structure of the company, we determined this venture to be a VIE consistent with ASU 2015-2. We have determined that we are not the primary beneficiary of the VIE and, therefore, we have not consolidated this entity. Additionally, we also will record the investment under the cost method as we have determined we do not exercise significant influence over the entity. We will assess our investment for impairment annually and, if a loss in value is deemed other than temporary, an impairment charge will be recorded. At December 31, 2018, the accumulated expected investment in the entity is $752,667 which is classified as an investment in unconsolidated entity in our consolidated balance sheets. The agreements were executed in January 2019 which is when we received our equity units for our services rendered. We account for the investments we make in certain legal entities in which equity investors do not have (1) sufficient equity at risk for the legal entity to finance its activities without additional subordinated financial support, or (2) as a group, the holders of the equity investment at risk do not have either the power, through voting or similar rights, to direct the activities of the legal entity that most significantly impact the entity’s economic performance, or (3) the obligation to absorb the expected losses of the legal entity or the right to receive expected residual returns of the legal entity. These legal entities are referred to as “variable interest entities” or “VIEs.” We would consolidate the results of any such entity in which we determined we had a controlling financial interest. We would have a “controlling financial interest” in such an entity if we had both the power to direct the activities that most significantly affect the VIE’s economic performance and the obligation to absorb the losses of, or right to receive benefits from, the VIE that could be potentially significant to the VIE. On a quarterly basis, we reassess whether we have a controlling financial interest in any investments we have in these legal entities. We determine whether any of the entities in which we have made investments is a VIE at the start of each new venture and if a reconsideration event has occurred. At such times, we also consider whether we must consolidate a VIE and/or disclose information about our involvement in a VIE. A reporting entity must consolidate a VIE if that reporting entity has a variable interest (or combination of variable interests) that will absorb a majority of the VIE’s expected losses, receive a majority of the VIE’s expected residual returns, or both. A reporting entity must consider the rights and obligations conveyed by its variable interests and the relationship of its variable interests with variable interests held by other parties to determine whether its variable interests will absorb a majority of a VIE’s expected losses, receive a majority of the VIE’s expected residual returns, or both. The reporting entity that consolidates a VIE is called the primary beneficiary of that VIE.

Loans Payable

Loans Payable	12 Months Ended
	Dec. 31, 2018
Text Block [Abstract]
Loans Payable	NOTE H – LOANS PAYABLE The Company’s consolidated notes payable consisted of the following: December 31, 2018 December 31, Note 1 – Monaco 2014 $ 2,800,000 $ 2,800,000 Note 2 – Monaco 2016 1,175,000 1,138,441 Note 3 – MINOSA 1 14,750,001 14,750,001 Note 4 – Epsilon 1,000,000 1,000,000 Note 5 – SMOM 3,500,000 3,000,000 Note 6 – MINOSA 2 5,050,000 4,675,000 Note 7 – Monaco 2018 1,099,366 — Note 8 – Promissory note 74,621 — $ 29,448,988 $ 27,363,442 Note 1 – Monaco 2014 On August 14, 2014, we entered into a Loan Agreement with Monaco Financial, LLC (“Monaco”), a strategic marketing partner, pursuant to which Monaco agreed to lend us up to $10.0 million. The loan was issued in three tranches: (i) $5.0 million (the “First Tranche”) was advanced upon execution of the Loan Agreement; (ii) $2.5 million (the “Second Tranche”) was advanced on October 1, 2014; and (iii) $2.5 million (the “Third Tranche”) was advanced on December 1, 2014. The Notes bear interest at a rate equal to 11% per annum. The Notes also contain an option whereby Monaco can purchase shares of Oceanica held by Odyssey (the “Share Purchase Option”) at a purchase price that is the lower of (a) $3.15 per share or (b) the price per share of a contemplated equity offering of Oceanica which totals $1.0 million or more in the aggregate. The share purchase option was not clearly and closely related to the host debt agreement and required bifurcation. On December 10, 2015, these promissory notes were amended as part of the asset acquisition agreement with Monaco (See NOTE R in our Form 10-K re-priced Note 2 – Monaco 2016 In March 2016, Monaco agreed to lend us an additional $1,825,000. These loan proceeds were received in full during the first quarter of 2016. The indebtedness bears interest at 10.0% percent per year. All principal and any unpaid interest was payable on April 15, 2018. This indebtedness has matured, but Monaco has not demanded payment because we are in negotiations with Monaco to set a new maturity date. As of the maturity date, the interest rate was adjusted to the default rate of 18% per annum. The current outstanding balance as of December 31, 2018 was $1,175,000. The indebtedness is convertible at any time until the maturity date into shares of Oceanica held by us at a conversion price of $1.00 per share. Pursuant to this loan and as security for the indebtedness, Monaco was granted a second priority security interest in (a) one-half deep-tow Accounting considerations ASC 815 generally requires the analysis of embedded terms and features that have characteristics of derivatives to be evaluated for bifurcation and separate accounting in instances where their economic risks and characteristics are not clearly and closely related to the risks of the host contract. The option to purchase the OMO Collateral is an embedded feature that is not clearly and closely related to the host debt agreement and thus requires bifurcation. Because the option is out of the money, it has no material fair value as of the inception date or currently. The debt agreement did not contain any additional embedded terms or features that have characteristics of derivatives. However, we were required to consider whether the hybrid contract embodied a beneficial conversion feature (“BCF”). The calculation of the effective conversion amount did result in a BCF because the effective conversion price was less than the market price on the date of issuance, therefore a BCF of $456,250 was recorded. This BCF has been fully amortized as of March 31, 2018. For the twelve-months ended December 31, 2018 and 2017, interest expense related to the discount in the amount of $0 and $252,940, respectively, was recorded. For the twelve months ended December 31, 2018 and 2017, accrued interest in the amount of $224,846 and $134,527, respectively, was recorded. Loan modification (December 2015) In connection with the Acquisition Agreement entered into with Monaco on December 10, 2015, Monaco agreed to modify certain terms of the loans as partial consideration for the purchase of assets. For the First Tranche ($5,000,000 advanced on August 14, 2014), Monaco agreed to cease interest as of December 10, 2015 and reduce the loan balance by (i) the cash or other value received from the SS Central America On December 10, 2015, the Monaco call option related to the Oceanica shares held by us was extended until December 31, 2017. Loan modification (March 2016) In connection with the $1.825 million loan agreement with Monaco in March 2016, the existing $2.8 million notes were modified. Of the combined total indebtedness of Monaco’s Note 1 and Note 2, Monaco can convert this debt into 3,174,603 shares of Oceanica at a fixed conversion price of $1.00 per share, or $3,174,603. Any remaining debt in excess of $3,174,603 is not convertible. Additionally, the modification eliminated Monaco’s option (“share purchase option”) to purchase 3,174,603 shares of Oceanica stock at a price of $3.15 per share. The modification was analyzed under ASC 480 Distinguishing Liabilities from Equity 470-50-40-10 pre-modification pre-modification 470-50-40-2 Step 1 pre-modification Monaco loans Loan one Forward cash flows: Principal $ 2,800,000 Interest 559,463 Total forward cash flows $ 3,359,463 Present value of forward cash flows $ 2,554,371 Fair value of equity conversion option 1,063,487 Fair value of debt $ 3,617,858 Significant inputs and results arising from the Binomial Lattice process are as follows for the conversion option that is classified in equity after the modification in March 2016: Underlying price on valuation date $1.25 Contractual conversion rate $1.00 Contractual term to maturity 1.82 Years Implied expected term to maturity 1.82 Years Market volatility: Range of volatilities 96.0% - 154.0% Equivalent volatilities 120.1% Risk free rates using zero coupon US Treasury Security rates 0.29% - 0.68% Equivalent market risk adjusted interest rates 0.52% Monaco loans Loan one Forward cash flows: Face value $ 2,800,000 Fair value 3,617,858 Difference (premium)* $ 817,858 *ASC 470-20-25-13 paid-in Step 2 pre-modification Allocation Derivative liabilities (share purchase options) $ 1,456,825 Monaco Loan (Old Debt) 3,372,844 Monaco Loan (New Debt) (2,800,000 ) APIC (Premium) (817,858 ) Difference to APIC* $ 1,211,811 *The difference between the fair value of the new debt and the sum of the pre-modification 470-50-40-2 Note 3 – MINOSA On March 11, 2015, in connection with a Stock Purchase Agreement, Minera del Norte, S.A. de C.V. (“MINOSA”) agreed to lend us up to $14.75 million. The entire $14.75 million was loaned in five advances from March 11 through June 30, 2015. The outstanding indebtedness bears interest at 8.0% percent per annum. The Promissory Note was amended on April 10, 2015 and on October 1, 2015 so that, unless otherwise converted as provided in the Note, the adjusted principal balance shall be due and payable in full upon written demand by MINOSA; provided that MINOSA agreed that it shall not demand payment of the adjusted principal balance earlier than the first to occur of: (i) 30 days after the date on which (x) SEMARNAT makes a determination with respect to the current application for the Manifestacion de Impacto Ambiental relating to phosphate deposit project, which determination is other than an approval or (y) Odyssey Marine Enterprises or any of its affiliates withdraws such application without MINOSA’s prior written consent; (ii) termination by Odyssey of the Stock Purchase Agreement, dated March 11, 2015 (the “Purchase Agreement”), among Odyssey, MINOSA, and Penelope Mining, LLC (the “Investor”); (iii) the occurrence of an event of default under the Promissory Note; (iv) December 31, 2015; or (v) if and only if the Investor shall have terminated the Purchase Agreement pursuant to Section 8.1(d)(iii) thereof, March 30, 2016. This indebtedness is classified as short-term debt. In connection with the loans, we granted MINOSA an option to purchase our 54% interest in Oceanica for $40.0 million (the “Oceanica Call Option”). On March 11, 2016, the Oceanica Call has expired. Completion of the transaction requires amending the Company’s articles of incorporation to (a) effect a reverse stock split, which was implemented on February 19, 2016, (b) adjusting the Company’s authorized capitalization, which was also implemented on February 19, 2016, and (c) establishing a classified board of directors (collectively, the “Amendments”). The Amendments have been or will be set forth in certificates of amendment to the Company’s articles of incorporation filed or to be filed with the Nevada Secretary of State. As collateral for the loan, we granted MINOSA a security interest in the Company’s 54% interest in Oceanica. The outstanding principal balance of this debt was $14.75 million at December 31, 2018. The maturity date of this indebtedness has been amended and matured on March 18, 2017. Per Note 6 MINOSA 2 below, the Minosa Purchase Agreement amended the due date of this note to a due date which may be no earlier than December 31, 2017, that is at least 60 days subsequent to written notice that Minosa intends to demand payment. See Note 6 – MINOSA 2 for further qualifications. During December 2017, MINOSA transferred this debt to its parent company. For the twelve months ended December 31, 2018 and 2017, accrued interest in the amount of $1,180,000 and $1,180,000, respectively, was recorded. Accounting considerations We have accounted for this transaction as a financing transaction, wherein the net proceeds received were allocated to the financial instruments issued. Prior to making the accounting allocation, we evaluated for proper classification under ASC 480 Distinguishing Liabilities from Equity Derivatives and Hedging Property, Plant and Equipment This debt agreement did not contain any embedded terms or features that have characteristics of derivatives. The Oceanica Call Option is considered a freestanding financial instrument because it is both (i) legally detachable and (ii) separately exercisable. The Oceanica Call Option did not fall under the guidance of ASC 480. Additionally, it did not meet the definition of a derivative under ASC 815 because the option has a fixed value of $40.0 million and does not contain an underlying variable which is indicative of a derivative. This instrument is considered an option contract for a sale of an asset. The guidance applied in this case is ASC 360-20, Based on the previous conclusions, we allocated the cash proceeds first to the debt at its present value using a market rate of 15%, which is management’s estimate of a market rate loan for the Company, with the residual allocated to the Oceanica Call Option, as follows: Tranche 1 Tranche 2 Tranche 3 Tranche 4 Tranche 5 Total Promissory Note $ 1,932,759 $ 5,826,341 $ 2,924,172 $ 1,960,089 $ 1,723,492 $ 14,366,853 Deferred Income (Oceanica Call Option) 67,241 173,659 75,828 39,911 26,509 383,148 Proceeds $ 2,000,000 $ 6,000,000 $ 3,000,000 $ 2,000,000 $ 1,750,001 $ 14,750,001 The call option amount of $383,148 represented a debt discount. This discount has been fully accreted up to face value using the effective interest method. Note 4 – Epsilon On March 18, 2016 we entered into a Note Purchase Agreement (“Purchase Agreement”) with Epsilon Acquisitions LLC (“Epsilon”). Pursuant to the Purchase Agreement, Epsilon loaned us $3.0 million in two installments of $1.5 million on March 31, 2016 and April 30, 2016. The indebtedness bears interest at a rate of 10% per annum and was due on March 18, 2017. We were also responsible for $50,000 of the lender’s out of pocket costs. This amount is included in the loan balance. In pledge agreements related to the loans, we granted security interests to Epsilon in (a) the 54 million cuotas (a unit of ownership under Panamanian law) of Oceanica Resources S. de R.L. (“Oceanica”) held by our wholly owned subsidiary, Odyssey Marine Enterprises, Ltd. (“OME”), (b) all notes and other receivables from Oceanica and its subsidiary owed to the Odyssey Pledgors, and (c) all of the outstanding equity in OME. Epsilon has the right to convert the outstanding indebtedness into shares of our common stock upon 75 days’ notice to us or upon a merger, consolidation, third party tender offer, or similar transaction relating to us at the conversion price of $5.00 per share, which represents the five-day Pursuant to the Purchase Agreement (a) we agreed to waive our rights to terminate the Stock Purchase Agreement in accordance with the terms thereof until December 31, 2016, and (b) MINOSA agreed to extend, until March 18, 2017, the maturity date of the $14.75 million loan extended by MINOSA to OME pursuant to the Stock Purchase Agreement. The indebtedness may be accelerated upon the occurrence of specified events of default including (a) OME’s failure to pay any amount payable on the date due and payable; (b) OME or we fail to perform or observe any term, covenant, or agreement in the Purchase Agreement or the related documents, subject to a five-day In connection with the execution and delivery of the Purchase Agreement, we and Epsilon entered into a registration rights agreement pursuant to which we agreed to register new shares of our common stock with a formal registration statement with the Securities and Exchange Commission upon the conversion of the indebtedness. Accounting considerations We have accounted for this transaction as a financing transaction, wherein the net proceeds received were allocated to the financial instruments issued. Prior to making the accounting allocation, we evaluated the transaction for proper classification under ASC 480 Distinguishing Liabilities from Equity Derivatives and Hedging Property, Plant and Equipment This debt agreement did not contain any embedded terms or features that have characteristics of derivatives. However, we were required to consider whether the hybrid contract embodied a beneficial conversion feature (“BCF”). The calculation of the effective conversion amount did result in a BCF because the effective conversion price was less than the Company’s stock price on the date of issuance, therefore a BCF of $96,000 was recorded. The BCF represents a debt discount which was amortized over the life of the loan. Loan modification (October 1, 2016) On October 1, 2016 Odyssey Marine Enterprises, Ltd. (“OME”), entered into an Amended and Restated Note Purchase Agreement (the “Restated Note Purchase Agreement”) with Epsilon Acquisitions LLC (“Epsilon”). In connection with the existing $3.0 million loan agreement, Epsilon agreed to lend an additional $3.0 million evidenced by secured convertible promissory notes. The convertible promissory notes bear an interest rate of 10.0% per annum and are due and payable on March 18, 2017. Epsilon has the right to convert all amounts outstanding under the Restated Note into shares of our common stock upon 75 days’ notice to OME or upon a merger, consolidation, third party tender offer, or similar transaction relating to us at the applicable conversion price, which is (a) $5.00 per share with respect to the $3.0 million already advanced under the Restated Note and (b) with respect to additional advances under the Restated Note, the five-day As an inducement for the issuance of the additional $3.0 million of promissory notes, we also delivered to Epsilon a common stock purchase warrant (the “Warrant”) pursuant to which Epsilon has the right to purchase up to 120,000 shares of our common stock at an exercise price of $3.52 per share, which exercise price represents the five-day Accounting considerations for additional tranches We evaluated for proper classification under ASC 480 Distinguishing Liabilities from Equity Derivatives and Hedging Property, Plant and Equipment Tranche 3 Tranche 4 Tranche 5 Promissory Note $ 981,796 $ 939,935 $ 1,000,000 Beneficial Conversion Feature (“BCF”)* 18,204 60,065 — Proceeds $ 1,000,000 $ 1,000,000 $ 1,000,000 A beneficial conversion feature arises when the calculation of the effective conversion price is less than the Company’s stock price on the date of issuance. Tranche 5 did not result in a BCF because the effective conversion price was greater than the company’s stock price on the date of issuance. The Warrant’s fair value was calculated using Black-Scholes Merton (“BSM”). The aggregate fair value of the Warrant totaled $303,712. Since the Warrant was issued as an inducement to Epsilon to issue additional debt, we recorded an inducement expense of $303,712. For the twelve months ended December 31, 2018 and 2017, accrued interest in the amount of $99,998 and $299,294, respectively, was recorded. Term Extension (March 21, 2017) On March 21, 2017 we entered into an amendment to the Restated Note Purchase Agreement with Epsilon. In connection with the existing $6.0 million of indebtedness, the adjusted principal balance is due and payable in full upon the earlier of (i) written demand by Epsilon or (ii) such time as Odyssey or the guarantor pays any other indebtedness for borrowed money prior to its stated maturity date. As such the Company amortized the notes up to their face value of $6,050,000 and they are classified as short-term. However, since Epsilon converted the first $3.0 million into 670,455 of our common shares and assigned $2.0 million to MINOSA, the current principal indebtedness at December 31, 2018 is $1.0 million. Note 5 – SMOM On May 3, 2017, we entered into a Loan and Security Agreement (“Loan Agreement”) with SMOM. Pursuant to the Loan Agreement, SMOM agreed to loan us up to $3.0 million as evidenced by a convertible promissory note. As a commitment fee, we assigned the remaining 50% of our Neptune Minerals, LLC receivable to SMOM. This receivable had zero carrying value on our balance sheet and due to the age and collectability was deemed to have no fair value. The indebtedness bears interest at a rate of 10% per annum and matures on the second anniversary of this Loan Agreement which is May 3, 2019. On April 20, 2018, the loan was amended, and the principal amount of the Loan was increased to $3,500,000. The loan balance at December 31, 2018 is $3.5 million. The holder has the option to convert up to $2.0 million of any unpaid principal and interest into up to 50% of the equity interest held by Odyssey in Aldama Mining Company, S.de R.L. de C.V. which is a wholly owned subsidiary of ours. The conversion value of $1.0 million equates to 10% of the equity interest in Aldama. If the holder elects to acquire the entire 50% of the equity interest, the Holder has to pay the deficiency in cash. As additional consideration for the loan, the holder has the right to purchase from Odyssey all or a portion of the equity collateral (up to the 50% of the equity interest of Aldama) for the option consideration ($1.0 million for each 10% of equity interests) during the period that is the later of (i) one year after the maturity date and (ii) one year after the loan is repaid in full, the expiration date. The lender may also choose to extend the expiration date annually by paying $500,000 for each year extended. For the twelve months ended December 31, 2018 and 2017, accrued interest in the amount of $330,822 and $204,863, respectively, was recorded. Accounting considerations We have accounted for this transaction as a financing transaction, wherein the net proceeds received were allocated to the financial instruments issued. Prior to making the accounting allocation, we evaluated for proper classification under ASC 480 Distinguishing Liabilities from Equity Derivatives and Hedging Property, Plant and Equipment This debt agreement did not contain any embedded terms or features that have characteristics of derivatives. However, we were required to consider whether the hybrid contract embodied a beneficial conversion feature (“BCF”). The calculation of the effective conversion amount did not result in a BCF because the effective conversion price was equal to the Company’s stock price on the date of issuance. Note 6 – MINOSA 2 On August 10, 2017, we entered into a Note Purchase Agreement (the “Minosa Purchase Agreement”) with MINOSA. Pursuant to the Minosa Purchase Agreement, MINOSA agreed to loan Enterprises up to $3.0 million. During 2017, we borrowed $2.7 million against this facility and Epsilon assigned $2.0 million of its debt to MINOSA. At December 31, 2018, the outstanding principal balance, including the Epsilon assignment, is $5.05 million. The indebtedness is evidenced by a secured convertible promissory note (the “Minosa Note”) and bears interest at a rate equal to 10.0% per annum. Unless otherwise converted as described below, the entire outstanding principal balance under this Minosa Note and all accrued interest and fees are due and payable upon written demand by MINOSA; provided, that MINOSA agreed not make a demand for payment prior to the earlier of (a) an event of default (as defined in the Minosa Note) or (b) a date, which may be no earlier than December 31, 2017, that is at least 60 days subsequent to written notice that MINOSA intends to demand payment. MINOSA has not provided any notice they intend to issue a payment demand notice. We unconditionally and irrevocably guaranteed all of the obligations under the Minosa Purchase Agreement and the Minosa Note. MINOSA has the right to convert all amounts outstanding under the Minosa Note into shares of our common stock upon 75 days’ notice to us or upon a merger, consolidation, third party tender offer, or similar transaction relating to us at the conversion price of $4.41 per share. During December 2017, MINOSA transferred this debt to its parent company. This debt agreement did not contain any embedded terms or features that have characteristics of derivatives. However, we were required to consider whether the hybrid contract embodied a beneficial conversion feature (“BCF”). The calculation of the effective conversion amount did result in a BCF because the effective conversion price was less than the Company’s stock price on the date of issuance, therefore a BCF of $62,925 was recorded. As of December 31, 2017, all of the BCF has been accreted to the income statement. The BCF represented a debt discount that was amortized over the life of the loan. For the twelve months ended December 31, 2018 and 2017, accrued interest in the amount of $504,075 and $142,110, respectively, was recorded. As previously reported, Epsilon loaned us an aggregate of $6.0 million pursuant to an amended and restated convertible promissory Minosa Note, dated as of March 18, 2016, as further amended and restated on October 1, 2016 (the “Epsilon Note”). Since then, Epsilon has assigned $2.0 million of the indebtedness under the Epsilon Note to MINOSA. Along with Epsilon, we entered into a second amended and restated convertible promissory note (the “Second AR Epsilon Note”), which further amends and restates the Epsilon Note. The stated principal amount of the Second AR Epsilon Note is $1.0 million (which reflects the outstanding principal balance remaining after giving effect to Epsilon’s (x) previous assignment of $2.0 million of the indebtedness under the Epsilon Note to MINOSA and (y) conversion of $3.0 million of the indebtedness under the Epsilon Note into shares of our common stock). The Second AR Epsilon Note further provides that the outstanding principal balance under the Second AR Epsilon Note and all accrued interest and fees are due and payable upon written demand by Epsilon; provided, that Epsilon agreed not make a demand for payment prior to the earlier of (a) an event of default (as defined in the Second AR Epsilon Note) or (b) a date, which may be no earlier than December 31, 2017, that is at least 60 days subsequent to written notice that MINOSA intends to demand payment. Upon the closing of the Minosa Purchase Agreement, along with MINOSA, and Penelope Mining LLC, an affiliate of Minosa (“Penelope”), executed and delivered a Second Amended and Restated Waiver and Consent and Amendment No. 5 to Promissory Note and Amendment No. 2 to Stock Purchase Agreement (the “Second AR Waiver”). Pursuant to the Second AR Waiver, Minosa and Penelope consented to the transactions contemplated by the Minosa Purchase Agreement and waived any breach of any representation or warranty and violation of any covenant in the Stock Purchase Agreement, dated as of March 11, 2015, as amended April 10, 2015 (the “SPA”), by and among us, Minosa, and Penelope, arising out of the Company’s execution and delivery of the Minosa Purchase Agreement and the consummation of the transactions contemplated thereby. Pursuant to the Second AR Waiver, we also waived, and agreed not to exercise our right to terminate the SPA pursuant to Section 8.1(c)(ii) thereto, both (a) until after the earlier of (i) July 1, 2018, (ii) the date that MINOSA fails, refuses, or declines to fund (or otherwise does not fund) any subsequent loan under the Minosa Purchase Agreement and (iii) demand is made for repayment of all or any part of the indebtedness outstanding under the Minosa Note, the Second AR Epsilon Note, or the Promissory Note, dated as of March 11, 2015, as amended (the “SPA Note”), in the principal amount of $14.75 million that was issued by us to MINOSA under the SPA, and (b) unless on or prior to such termination, the Notes are paid in full. The Second AR Waiver (x) further provides that following any conversion of the indebtedness evidenced by the Minosa Note, Penelope may elect to reduce its commitment to purchase our preferred stock under the SPA by the amount of indebtedness converted by MINOSA and (y) amends the SPA Note to provide that the outstanding principal balance under the SPA Note and all accrued interest and fees are due and payable upon written demand by MINOSA; provided, that Minosa agreed not make a demand for payment prior to the earlier of (a) an event of default (as defined in the Minosa Note) or (b) a date, which may be no earlier than December 31, 2017, that is at least 60 days subsequent to written notice that Minosa intends to demand payment. The obligations under the Minosa Note may be accelerated upon the occurrence of specified events of default including (a) our failure to pay any amount payable under the Minosa Note on the date due and payable; (b) our failure to perform or observe any term, covenant, or agreement in the Minosa Note or the related documents, subject to a five-day Pursuant to second amended and restated pledge agreements (the “Second AR Pledge Agreements”) entered into by us in favor of MINOSA, we pledged and granted security interests to MINOSA in (a) the 54 million cuotas (a unit of ownership under Panamanian law) of Oceanica held by us, (b) all notes and other receivables from Oceanica and its subsidiary owed to us, and (c) all of the outstanding equity in our wholly owned subsidiary, Odyssey Marine Enterprises, Ltd. In connection with the execution and delivery of the Minosa Purchase Agreement, Odyssey and MINOSA entered into a second amended and restated registration rights agreement (the “Second AR Registration Rights Agreement”) pursuant to which Odyssey agreed to register the offer and sale of the shares (the “Conversion Shares”) of our common stock issuable upon the conversion of the indebtedness evidenced by the Minosa Note. Subject to specified limitations set forth in the Second AR Registration Rights Agreement, including that we are eligible to use Form S-3, Note 7 – Monaco 2018 During the period ended March 31, 2018, Monaco advanced us $1.0 million that was applied to a loan agreement that was executed on April 20, 2018. Monaco also agreed to treat $99,366 of back rent owed by us to Monaco as part of this loan resulting in an aggregate principal amount of $1,099,366 at December 31, 2018. The indebtedness bears interest at 10.0% percent per year. All principal and any unpaid interest is to be payable on the first anniversary of this agreement, April 20, 2019. This debt is secured by cash proceeds, if any, from our future shipwreck projects we have contracted with Magellan. As additional consideration, their share purchase option expiration date, as discussed in Note 1 – Monaco 2014 and Note 2 – Monaco 2016 above, has been extended from 30 days to seven months after the note becomes paid in full. For the twelve months ended December 31, 2018 and 2017, accrued interest in the amount of $79,539 and $0, respectively, was recorded. Note 8 – Promissory note On July 12, 2018, we entered into a Note and Warrant Purchase Agreement (the “Purchase Agreement”) with two individuals (the “Lenders”), one of whom holds in excess of 5.0% of our outstanding common stock. Pursuant to the Purchase Agreement, the Lenders agreed to lend an aggregate of $1,050,000 to us, which was advanced in three tranches on July 12, 2018, $500,000, August 17, 2018, $300,000 and October 4, 2018, $250,000. The indebtedness is evidenced by secured convertible promissory notes (the “Notes”) and bears interest at a rate equal to 8.0% per annum. Unless otherwise converted as described below, the entire outstanding principal balance under the Notes and all accrued interest and fees are due and payable on July 12, 2019. At any time after to the first to occur of (a) a sale by us of additional Notes or (b) September 12, 2018, the Lenders have the right to convert all amounts outstanding under the Notes into either (x) shares of our common stock at the conversion rate of $8.00 per share, (y) $500,000 of the indebtedness owed by Exploraciones Oceanicas S. de R. L. de C.V. (“ExO”) to Oceanica Marine Operations, S.R.L. (“OMO”), or (z) a 7.5% interest in Aldama Mining Company, S. de R. L. de C.V. (“Aldama”). We indirectly hold a controlling interest in ExO; OMO and Aldama are indirect, wholly owned subsidiaries of ours. In connection with the issuance and sale of the Notes, we issued warrants to purchase common stock (the “Warrants”) to the Lenders. The Lenders may exercise the Warrants to purchase an aggregate of 50,000 shares of our common stock at an exercise price of $12.00 per share. The Warrants are exercisable during the period commencing on the date on which the Notes are converted into shares of our common stock and ending on July 12, 2021. Pursuant to a Pledge Agreement, dated as of July 12, 2018 (the “Pledge Agreement”), our obligations under the Notes are secured by a pledge of a portion of Odyssey’s ownership interest in Aldama and another entity. Pursuant to a Registration Rights Agreement (the “Rights Agreement”) among us and the Lenders, we granted the Lenders “piggy-back” registration rights with respect to the shares of our common stock issuable upon conversion of the Notes and the exercise of the Warrants. The Purchase Agreement, the Notes, the Warrants, the Pledge Agreement, and the Rights Agreement include representations and warranties and other covenants, conditions, and other provisions customary for comparable transactions. We have accounted for this transaction as a financing transaction, wherein the net proceeds received were allocated to the financial instruments issued. Prior to making the accounting allocation, we evaluated the transaction for proper classification under ASC 480 Distinguishing Liabilities from Equity (“ASC 480”), ASC 815 Derivatives and Hedging (“ASC 815”). We determined that the debt achieved conventional convertible status and that the equity conversion option was in the money at inception which required the calculation of a beneficial conversion feature (“BCF”). The fair value of the warrants and BCF component exceeded the amount of proceeds, therefore, they were limited to the cash proceeds of $1,050,000 at December 31, 2018. As a result, there was no value allocated to the debt at inception. The debt is being accreted to face value over its term using the effective interest method. For the twelve months ended December 31, 2018, we recorded $74,621 in interest expense associated with the accretion of the debt discount and the carrying value of the notes at December 31, 2018 was $74,621. Therefore, the book balance of this debt at December 31, 2018 is $74,621 and the actual face value is $1.05 million. For the twelve months ended December 31, 2018 and 2017, accrued interest in the amount of $33,284 and $0, respectively, was recorded. Long-Term Obligation Maturities We do not have any long-term obligations that mature beyond 12 months from December 31, 2018. 2019 is the third year of our three year corporate headquarter operating lease. We entered into the operating lease with Monaco Financial, LLC, a related party; however, the buil

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2018
Payables and Accruals [Abstract]
Accrued Expenses	NOTE I – ACCRUED EXPENSES Accrued expenses consist of the following: 2018 2017 Compensation and incentives $ 2,567,732 $ 1,871,071 Professional services 400,367 329,640 Interest 6,508,621 4,056,337 Accrued insurance obligations 309,826 249,247 Other operating 18,000 45,040 Total accrued expenses $ 9,804,546 $ 6,551,335 Professional fees are mainly attributable to legal fees and related and other professional services in support of operations. Included in Professional fees are $230,500 of fees earned by Greg Stemm, former chief executive office and current chairman of the board, in accordance to his consulting service agreement executed in 2015. These fees are to be paid out monthly over 2019 and beyond. Mr. Stemm has an additional $80,509 of fees due in accounts payable at December 31, 2018. These fees will be remitted at a mutually agreeable time in the future. Compensation and incentives includes $1.8 million accrued incentive awards for the company employees for 2017 and prior and $0.8 million for 2018. However, the Board of Directors will only approve incentives to be paid when and if there is sufficient excess cash above and beyond normal operating requirements. Other operating expenses contain general items due resulting from general operations. Accrued interest is due to several lenders per debt agreements described in NOTE H.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2018
Related Party Transactions [Abstract]
Related Party Transactions	NOTE J – RELATED PARTY TRANSACTIONS On December 9, 2002, a Georgia limited liability company acquired rights from an unrelated third party through a foreclosure sale to receive 5% of post-finance cost proceeds, if any, from shipwrecks that we may recover within a predefined search area of the Mediterranean Sea. The shipwreck we believe to be HMS Sussex Based on the economic substance of our business transactions with Monaco Financial, LLC, we consider Monaco to be an affiliated company, thus a related party. We do not own any financial interest in Monaco. We had accounts receivable with Monaco and related affiliates at December 31, 2018 of $612,498 and at December 31, 2017 of $183,453. We had general operating payables with Monaco at December 31, 2018 of $233,855 and at December 31, 2017 of $200,801. See NOTE H for further debt arrangements between the entities. During 2018, we performed marine shipwreck search and recovery services for this related party and recognized year to date revenue of $2.2 million. Until October 2018, we leased our corporate office space on an annually renewable basis from Monaco at $20,080 per month; however, the building in which we lease this space was sold during October 2018 to a non-affiliate. During 2018, we provided services to a deep-sea

Deferred Income and Revenue Par

Deferred Income and Revenue Participation Rights	12 Months Ended
	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Deferred Income and Revenue Participation Rights	NOTE K – DEFERRED INCOME AND REVENUE PARTICIPATION RIGHTS The Company’s participating revenue rights and deferred revenue consisted of the following for the respective year end: December 31, 2018 December 31, 2017 “ Cambridge $ 825,000 $ 825,000 “ Seattle 62,500 62,500 Galt Resources, LLC (HMS Victory 3,756,250 3,756,250 Total revenue participation rights $ 4,643,750 $ 4,643,750 “ Cambridge ” project We previously sold Revenue Participation Certificates (“RPCs”) that represent the right to share in our future revenues derived from the “ Cambridge Sussex Cambridge” Each $50,000 convertible “ Cambridge” Cambridge Cambridge Cambridge “ Seattle ” project In a private placement that closed in September 2000, we sold “units” consisting of “ Republic” Seattle Republic Seattle The participating rights balance will be amortized under the units of revenue method once management can reasonably estimate potential revenue for each of these projects. The RPCs for the “ Cambridge Seattle” Galt Resources, LLC In February 2011, we entered into a project syndication deal with Galt Resources LLC (“Galt”) for which they invested $7,512,500 representing rights to future revenues of any one project Galt selected prior to December 31, 2011. If the project is successful and generates sufficient proceeds, Galt will recoup their investment plus three times the investment. Galt’s investment return will be paid out of project proceeds. Galt will receive 50% of project proceeds until this amount is recouped. Thereafter, they will share in additional net proceeds of the project at the rate of 1% for every million invested. Subsequent to the original syndication deal, we reached an agreement permitting Galt to bifurcate their selection between two projects, the SS Gairsoppa Victory Victory Victory Gairsoppa Gairsoppa Victory

Stockholders' Equity_(Deficit)

Stockholders' Equity/(Deficit)	12 Months Ended
	Dec. 31, 2018
Federal Home Loan Banks [Abstract]
Stockholders' Equity/(Deficit)	NOTE L – STOCKHOLDERS’ EQUITY/(DEFICIT) Common Stock On October 31, 2018, we sold in the aggregate 700,000 shares of our common stock and warrants to purchase up to 700,000 shares of our common stock. The common stock and warrants were sold in units, with each unit consisting of one share of common stock and a warrant to purchase one shares of common stock. The purchase price for each unit is $7.155. The warrants have an exercise price of $7.155 per share of common stock and are exercisable in accordance with their terms at any time on or before the close of business on November 2, 2023. In April 2017, Epsilon converted $3.3 million of their principal and accrued interest into 670,455 shares of our common stock at a conversion price of $5.00. See NOTE H for further information. Convertible Preferred Stock On March 11, 2015, we entered into a Stock Purchase Agreement (the “Purchase Agreement”) with Penelope Mining LLC (the “Investor”), and, solely with respect to certain provisions of the Purchase Agreement, Minera del Norte, S.A. de C.V. (the “Lender”). The Purchase Agreement provides for the Company to issue and sell to the Investor shares of the Company’s preferred stock in the amounts set forth in the following table (numbers have been adjusted for the February 2016 reverse stock split): Convertible Preferred Stock Shares Price Per Share Total Investment Series AA-1 8,427,004 $ 12.00 $ 101,124,048 Series AA-2 7,223,145 $ 6.00 43,338,870 15,650,149 $ 144,462,918 The Investor’s option to purchase the Series AA-2 The closing of the sale and issuance of shares of the Company’s preferred stock to the Investor is subject to certain conditions, including the Company’s receipt of required approvals from the Company’s stockholders, the receipt of regulatory approval, performance by the Company of its obligations under the Stock Purchase Agreement, the listing of the underlying common stock on the NASDAQ Stock Market and the Investor’s satisfaction, in its sole discretion, with the viability of certain undersea mining projects of the Company. This transaction received stockholders’ approval on June 9, 2015. Completion of the transaction requires amending the Company’s articles of incorporation to (a) effect a reverse stock split, which was done on February 19, 2016, (b) adjusting the Company’s authorized capitalization, which was also done on February 19, 2016, and (c) establishing a classified board of directors (collectively, the “Amendments”). The Amendments have been or will be set forth in certificates of amendment to the Company’s articles of incorporation filed or to be filed with the Nevada Secretary of State. Series AA Convertible Preferred Stock Designation The Purchase Agreement provides for the issuance of up to 8,427,004 shares of Series AA-1 AA-1 AA-2 AA-2 Dividends Liquidation Preference 360-day 30-day Voting Rights Conversion Rights non-assessable Adjustments to Conversion Rights Accounting considerations As stated above the issuance of the Series AA Convertible Preferred Stock is based on certain contingencies. No accounting treatment determination is required until these contingencies are met and the Series AA Convertible Preferred Stock has been issued. However, we have analyzed the instrument to determine the proper accounting treatment that will be necessary once the instruments have been issued. ASC 480 generally requires liability classification for financial instruments that are certain to be redeemed, represent obligations to purchase shares of stock or represent obligations to issue a variable number of common shares. We concluded that the Series AA Preferred was not within the scope of ASC 480 because none of the three conditions for liability classification was present. ASC 815 generally requires the analysis of embedded terms and features that have characteristics of derivatives to be evaluated for bifurcation and separate accounting in instances where their economic risks and characteristics are not clearly and closely related to the risks of the host contract. However, in order to perform this analysis, we were first required to evaluate the economic risks and characteristics of the Series AA Convertible Preferred Stock in its entirety as being either akin to equity or akin to debt. Our evaluation concluded that the Series AA Convertible Preferred Stock was more akin to an equity-like contract largely due to the fact that most of its features were participatory in nature. As a result, we concluded that the embedded conversion feature is clearly and closely related to the host equity contract and will not require bifurcation and liability classification. The option to purchase the Series AA-2 Stock-Based Compensation We have two stock incentive plans. The first is the 2005 Stock Incentive Plan that expired in August 2015. After the expiration of this plan, equity instruments cannot be granted but this plan will continue in effect until all outstanding awards have been exercised in full or are no longer exercisable and all equity instruments have vested or been forfeited. On June 9, 2015, our shareholders approved our 2015 Stock Incentive Plan (the “Plan”) that was adopted by our Board of Directors (the “Board”) on January 2, 2015, which is the effective date. The plan expires on the tenth anniversary of the effective date. The Plan provides for the grant of incentive stock options, non-qualified non-qualified Share-based compensation expense recognized during the period is based on the value of the portion of share-based payment awards that is ultimately expected to vest. As share-based compensation expense recognized in the statement of operations is based on awards ultimately expected to vest, it can be reduced for estimated forfeitures. The ASC topic Stock Compensation requires forfeitures to be estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. The share-based compensation charged against income for the periods ended December 31, 2018, 2017 and 2016 was $415,615, $833,985 and $1,778,461, respectively. We did not grant stock options to employees in 2018. We did grant options to two outside directors in 2016 for their quarterly fees related to the last three quarters of the year. The weighted average estimated fair value of stock options granted during the fiscal years ended December 31, 2018, 2017 and 2016 were $0.00, $0.00 and $1.75, respectively. These amounts were determined using the Black-Scholes option-pricing model, which values options based on the stock price at the grant date, the expected life of the option, the estimated volatility of the stock, the expected dividend payments, and the risk-free interest rate over the life of the option. The assumptions used in the Black-Scholes model were as follows for stock options granted in the years ended December 31, 2018, 2017 and 2016: 2018 2017 2016 Risk-free interest rate — — 1.29 - 2.25% Expected volatility of common stock — — 80.87 - 82.69% Dividend yield — — 0% Expected life of options — — 8.2 years The Black-Scholes option valuation model was developed for estimating the fair value of traded options that have no vesting restrictions and are fully transferable. Because option valuation models require the use of subjective assumptions, changes in these assumptions can materially affect the fair value of the options. Our options do not have the characteristics of traded options; therefore, the option valuation models do not necessarily provide a reliable measure of the fair value of our options. Additional information with respect to both plans stock option activity is as follows: Number of Shares Weighted Average Exercise Price Outstanding at December 31, 2015 375,283 $ 32.04 Granted 22,493 $ 2.74 Exercised — $ — Cancelled (65,361 ) $ 32.82 Outstanding at December 31, 2016 332,415 $ 21.55 Granted — $ — Exercised — $ — Cancelled (84,598 ) $ 35.59 Outstanding at December 31, 2017 247,817 $ 16.76 Granted — $ — Exercised — $ — Cancelled (9,166 ) $ 36.52 Outstanding at December 31, 2018 238,651 $ 15.95 Options exercisable at December 31, 2016 300,751 $ 22.30 Options exercisable at December 31, 2017 247,817 $ 16.76 Options exercisable at December 31, 2018 238,651 $ 15.95 The aggregate intrinsic values of options exercisable for the fiscal years ended December 31, 2018, 2017 and 2016 were $15,564, $0 and $16,633, respectively. The aggregate intrinsic values of options outstanding for the fiscal years ended December 31, 2018, 2017 and 2016 were $15,564, $0 and $16,633, respectively. The aggregate intrinsic values of options exercised during the fiscal years ended December 31, 2018, 2017 and 2016 are $0, $0 and $0, respectively, determined as of the date of the option exercise. Aggregate intrinsic value represents the positive difference between our closing stock price at the end of a respective period and the exercise price multiplied by the number of relative options. The total fair value of options vested during the fiscal years ended December 31, 2018, 2017 and 2016 was $0, $231,952 and $828,497, respectively. As of December 31, 2018, there was no remaining amount of unrecognized compensation cost related to unvested share-based compensation awards granted to employees under the option plans. Therefore, there is no cost to be recognized over any future weighted average periods. The following table summarizes information about stock options outstanding at December 31, 2018: Stock Options Outstanding Range of Exercise Prices Number of Shares Weighted Average Weighted Average Exercise $26.40 - $26.40 75,158 5.00 $ 26.40 $12.48 - $12.84 141,000 6.00 $ 12.48 $2.02 - $3.59 22,493 7.65 $ 2.74 238,651 5.84 $ 15.95 The estimated fair value of each restricted stock award is calculated using the share price at the date of the grant. A summary of the status of the restricted stock awards as of December 31, 2018 and changes during the year ended December 31, 2018 is presented as follows: Number of Weighted Average Unvested at December 31, 2017 132,826 $ 5.90 Granted — $ — Vested (91,159 ) $ 3.55 Cancelled — $ — Unvested at December 31, 2018 41,667 $ 11.04 The fair value of restricted stock awards vested during the years ended December 31, 2018, 2017 and 2016 was $323,614, $408,466 and $715,406, respectively. The fair value of unvested restricted stock awards remaining at the periods ended December 31, 2018, 2017 and 2016 is $460,000, $500,754 and $817,110, respectively. The weighted-average grant date fair value of restricted stock awards granted during the periods ended December 31, 2018, 2017 and 2016 were nil, nil and $3.54, respectively. The weighted-average remaining contractual term of these restricted stock awards at the periods ended December 31, 2018, 2017 and 2016 are 0.8, 1.0 and 2.0 years, respectively. As of December 31, 2018, there was a total of $69,000 unrecognized compensation cost related to unvested restricted stock awards. The following table summarizes our common stock warrants outstanding at December 31, 2018: Common Stock Warrants Exercise Price Termination Date 120,000 $ 3.52 10/01/2021 65,625 $ 12.00 07/12/2021 700,000 7.16 11/02/2023 885,625 Cuota Appreciation Rights On August 4, 2017, the Company’s board of directors (the “Board”) adopted the Odyssey Marine Exploration, Inc. Key Employee Cuota Appreciation Rights (the “Key Employee Plan”) and the Odyssey Marine Exploration, Inc. Nonemployee Director Cuota Appreciation Rights (the “Director Plan” and, together with the Key Employee Plan, the “Cuota Plans”). The Cuota Plans provide for the award of cuota appreciation rights (“CARs”) to eligible participants. A “cuota” is a unit of equity interest under Panamanian law, and the value of the CARs will be determined based upon the appreciation, if any, in the value of the cuotas of Oceanica Resources, S. de R.L., a Panamanian sociedad de responsabilidad limitada (“Oceanica”), after the award of such CARs. The Company indirectly holds a majority stake in Oceanica. The Board authorized the award of up to 750,000 CARs under the Key Employee Plan and the award of up to 600,000 CARs under the Director Plan. The terms of any CARs awarded under the Cuota Plans will be set forth in an award agreement between the Company and each participant, and the award agreement will set forth a vesting schedule for the CARs. In general, unvested CARs will be forfeited upon a participant’s separation of service from the Company, and all vested and unvested CARs will be forfeited upon a participant’s separation of service from the Company for “cause” (as defined in the Cuota Plans). Each participant in the Cuota Plans will be entitled to be paid the value of such participant’s CARs upon the occurrence of a “payment event.” As used in the Cuota Plans, payment events consist of a change in control of the Company or the date specified in the applicable award agreement and, in the case of the Key Employee Plan, a separation of service without cause and the participant’s continuous employment with the Company until the date specified in the applicable award agreement. The value of CARs liability will be based upon the difference between the basis in the cuotas of Oceanica on the date of the award of the CARs, which is $3.00, and the fair value of the cuotas on the date used for the payment event, in each case as determined by the Board in accordance with the provisions of the Cuota Plans. The fair value of the cuota as of October 31, 2018 is $1.53. The following is an analysis of activity in the CARs balances as of December 31, 2018: Number of CARs Key Employee Plan Nonemployee Director Plan Unvested at December 31, 2017 229,076 — Granted 406,384 278,000 Vested (249,880 ) (278,000 ) Cancelled — — Unvested at December 31, 2018 385,580 — At December 31, 2018, there was no liability or associated compensation cost associated with these CARs. At December 31, 2018, there were 364,420 vested CARs outstanding and there were no excercisable CARs outstanding related to the Key Employee Plan. The CARs in the Nonemployee Director Plan are utilized as compensation for services, therefore these CARs vest upon grant. At December 31, 2018, the Nonemployee Director Plan had 500,000 CARs vested and outstanding. Since there is not a readily available market that would value the cuota, we use the services of an outside professional and independent valuation firm to determine the fair value of the Cuota.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	NOTE M – INCOME TAXES As of December 31, 2018, the Company had consolidated income tax net operating loss (“NOL”) carryforwards for federal tax purposes of approximately $167,402,048 and net operating loss carryforwards for foreign income tax purposes of approximately $39,589,337. The federal NOL carryforwards from 2005 forward will expire in various years beginning 2025 and ending through the year 2037. From 2025 through 2027, approximately $43 million of the NOL will expire, and from 2028 through 2036, approximately $116 million of the NOL will expire. The NOL generated in 2018 of approximately $8M will be carried forward indefinitely. The components of the provision for income tax (benefits) are attributable to continuing operations as follows: December 31, December 31, December 31, Current Federal $ — $ — $ — State — — — $ — $ — $ — Deferred Federal $ — $ — $ — State — — — $ — $ — $ — Deferred income taxes reflect the net tax effects of the temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of the Company’s deferred tax assets and liabilities as of December 31, 2018 are as follows: Deferred tax assets: Net operating loss and tax credit carryforwards $ 48,404,432 Capital loss carryforward 147,552 Accrued expenses 559,096 Reserve for Dorado accounts receivable 287,335 Start-up 7,042 Excess of book over tax depreciation 707,044 Stock option and restricted stock award expense 1,331,067 Investment in unconsolidated entities 1,387,970 Less: valuation allowance (52,684,059 ) $ 147,479 Deferred tax liability: Property and equipment basis $ 43,155 Prepaid expenses 104,324 $ 147,479 Net deferred tax asset $ — As reflected above, we have recorded a net deferred tax asset of $0 at December 31, 2018. As required by the Accounting for Income Taxes topic in the ASC, we have evaluated whether it is more likely than not that the deferred tax assets will be realized. Based on the available evidence, we have concluded that it is more likely than not that those assets would not be realized without the recovery and rights of ownership or salvage rights of high-value shipwrecks or other forms of taxable income, thus a valuation allowance has been recorded as of December 31, 2018. The change in the valuation allowance is as follows: December 31, 2018 $ 52,684,059 December 31, 2017 49,235,133 Change in valuation allowance $ 3,448,926 On December 22, 2017, the Tax Cuts and Jobs Act (the “Act”) was signed into United States tax law. The Company has adjusted its deferred tax assets, deferred tax liabilities, and valuation allowance at December 31, 2017 to reflect the Act’s reduction of corporate income tax rates. The federal and state income tax provision (benefit) is summarized as follows for the years ended: December 31, December 31, December 31, Expected (benefit) $ (1,923,757 ) $ (3,718,058 ) $ (2,186,550 ) Effects of: State income taxes net of federal benefits (92,707 ) (110,667 ) (65,082 ) Nondeductible expense 29,670 711,679 (1,083,185 ) Change in valuation allowance 3,765,560 28,258,724 4,189,828 Foreign Rate Differential (1,778,766 ) (1,097,681 ) (855,011 ) Change in Deferred Taxes due to enacted changes in tax law — (24,043,997 ) — $ — $ — $ — The Company’s effective income tax rate is lower than what would be expected if the federal statutory rate were applied to income before income taxes primarily because of certain expenses deductible for financial reporting purposes that are not deductible for tax purposes, research and development tax credits, operating loss carryforwards, and adjustments to previously-recorded deferred tax assets and liabilities due to the enactment of the Tax Cuts and Jobs Act. We have not recognized a material adjustment in the liability for unrecognized tax benefits and have not recorded any provisions for accrued interest and penalties related to uncertain tax positions. The earliest tax year still subject to examination by a major taxing jurisdiction is 2015.

Major Customers

Major Customers	12 Months Ended
	Dec. 31, 2018
Text Block [Abstract]
Major Customers	NOTE N – MAJOR CUSTOMERS For the fiscal year ended December 31, 2018, we had two customers that accounted for 97.0% of our total revenue. During the fiscal year ended December 31, 2017, we had one customer that accounted for 99.0% of our total revenue.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	NOTE O – COMMITMENTS AND CONTINGENCIES Rights to Future Revenues, If Any We have sold the rights to share in future revenues, if any, with respect to the “ Seattle Cambridge Sussex Sussex To date, the only income derived from these projects resulted in a one-time Cambridge” In addition, on May 26, 1998, we signed an agreement with a subcontractor that entitled it to receive 5% of the post finance cost proceeds from any shipwrecks in a predefined search area of the Mediterranean Sea. A shipwreck we have found, which we believe to be HMS Sussex In February 2011, we entered into a project syndication deal with Galt Resources LLC (“Galt”) for which they invested $7,512,500 representing rights to future revenues of any project of Galt’s choosing. This amount has been bifurcated equally between the SS Gairsoppa Victory Gairsoppa Legal Proceedings The Company may be subject to a variety of other claims and lawsuits that arise from time to time in the ordinary course of business. We are currently not a party to any pending litigation. Contingency During March 2016, our Board of Directors approved the grant and issuance of 3.0 million new equity shares of Oceanica Resources, S.R.L. to two attorneys for their future services. This equity is only issuable upon the Mexican’s government approval of the Environmental Impact Assessment (“EIA”) for our Mexican subsidiary. This grant of new shares was also approved by the Administrators of Oceanica Resources, S.R.L. We also owe consultants contingent success fees of up to $425,000 upon the approval and issuance of the EIA. The EIA has not been approved as of the date of this report. Going Concern Consideration We have experienced several years of net losses and may continue to do so. Our ability to generate net income or positive cash flows for the following twelve months is dependent upon our success in developing and monetizing our interests in mineral exploration entities, generating income from exploration charters, collecting on amounts owed to us, and completing the MINOSA/Penelope equity financing transaction approved by our stockholders on June 9, 2015. Our 2019 business plan requires us to generate new cash inflows to effectively allow us to perform our planned projects. We plan to generate new cash inflows through the monetization of our receivables and equity stakes in seabed mineral companies, financings, syndications or other partnership opportunities. If cash inflow is not sufficient to meet our desired projected business plan requirements, we will be required to follow a contingency business plan which is based on curtailed expenses and fewer cash requirements. On March 11, 2015, we entered into a Stock Purchase Agreement with Minera del Norte S.A. de c.v. (“MINOSA”) and Penelope Mining LLC (“Penelope”), an affiliate of MINOSA, pursuant to which (a) MINOSA agreed to extend short-term, debt financing to Odyssey of up to $14.75 million, and (b) Penelope agreed to invest up to $101 million over three years in convertible preferred stock of Odyssey. The equity financing is subject to the satisfaction of certain conditions, including the approval of our stockholders which occurred on June 9, 2015, and MINOSA and Penelope are currently under no obligation to make the preferred share equity investments. (See Item 7, Management’s Discussion and Analysis of Financial Condition and Results of Operations—Financings.) Our consolidated non-restricted

Quarterly Financial Data - Unau

Quarterly Financial Data - Unaudited	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data - Unaudited	NOTE P – QUARTERLY FINANCIAL DATA – UNAUDITED The following tables present certain unaudited consolidated quarterly financial information for each of the past eight quarters ended December 31, 2018 and 2017. This quarterly information has been prepared on the same basis as the Consolidated Financial Statements and includes all adjustments necessary to state fairly the information for the periods presented. Fiscal Year Ended December 31, 2018 Quarter Ending March 31 June 30 September 30 December 31 Revenue – net $ 511,735 $ 1,073,479 $ 886,327 $ 804,212 Gross profit 511,735 1,073,479 886,327 804,212 Net income (loss) (1,744,762 ) (641,557 ) (1,309,275 ) (1,476,842 ) Basic and diluted net income per share $ (0.21 ) $ (0.08 ) $ (0.15 ) $ (0.16 ) Fiscal Year Ended December 31, 2017 Quarter Ending March 31 June 30 September 30 December 31 Revenue – net $ 649,353 $ 587,270 $ 11,854 $ — Gross profit 649,353 587,270 11,854 — Net income (loss) (2,199,263 ) (1,916,885 ) (2,251,097 ) (1,392,227 ) Basic and diluted net income per share $ (0.28 ) $ (0.23 ) $ (0.27 ) $ (0.17 )

Other Debt

Other Debt	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Other Debt	NOTE Q – OTHER DEBT We currently owe a vendor approximately $0.6 million as a trade payable. This trade payable bears a simple annual interest rate of 12%. As collateral, they were granted a primary lien on certain items of our marine equipment. The carrying value of this equipment is zero. This agreement matured in August of 2018. During the three-months ended June 30, 2018, we sold various marine equipment to Magellan for $1.0 million and the assumption of this vendor’s trade payable and accrued interest, however, we remain as guarantor on this trade payable. We recorded a gain of approximately $0.9 million from the cash proceeds alone. Included in this equipment is the equipment noted above the vendor has a primary lien on. The vendor has consented to Magellan’s assumption of this debt but did not release us from our obligations. If Magellan defaults and the vendor forecloses on this equipment currently in possession of Magellan we then have a contingent liability to Magellan in the amount of $0.5 million for two of the key assets.

SCHEDULE II - VALUATION and QUA

SCHEDULE II - VALUATION and QUALIFYING ACCOUNTS	12 Months Ended
	Dec. 31, 2018
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
SCHEDULE II - VALUATION and QUALIFYING ACCOUNTS	SCHEDULE II – VALUATION and QUALIFYING ACCOUNTS For the Fiscal Years of 2016, 2017 and 2018 ODYSSEY MARINE EXPLORATION, INC. AND SUBSIDIARIES Balance at Charged Charged Deductions Balance at Inventory reserve 2016 — — — — — 2017 — — — — — 2018 — — — — — Accounts receivable reserve 2016 2,315,797 — 29,932 — 2,345,729 2017 2,345,729 — — (2,345,729 ) — 2018 — — — — —

Organization and Summary of S_2

Organization and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Equity Method Investments and Joint Ventures [Abstract]
Organization	Organization Odyssey Marine Exploration, Inc. and subsidiaries (the “Company,” “Odyssey,” “us,” “we” or “our”) is engaged in deep-ocean exploration. Our innovative techniques are currently applied to mineral exploration, shipwreck cargo recovery, and other marine survey and exploration charter services. Our corporate headquarters are located in Tampa, Florida.
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies This summary of significant accounting policies of the Company is presented to assist in understanding our financial statements. The financial statements and notes are representations of the Company’s management who are responsible for their integrity and objectivity and have prepared them in accordance with our customary accounting practices.
Recent accounting pronouncements	Recent accounting pronouncements In May 2014, the Financial Accounting Standards Board, or the FASB, issued Accounting Standards Update 2014-09, Revenue from Contracts with Customers 2014-09, In February 2016, the FASB issued Accounting Standards Update (ASU) 2016-02, Leases In May 2017, the FASB issued ASU 2017-09, Compensation-Stock Compensation (Topic 718), Scope of Modification Accounting. In July 2017, the FASB issued Accounting Standards Update No. 2017-11, Earnings Per Share (Topic 260), Distinguishing Liabilities from Equity (Topic 480), Derivatives and Hedging (Topic 815). 470-20, In March 2018, the FASB issued ASU No. 2018-05, Income Taxes Other recent accounting pronouncements issued by the FASB, the AICPA and the SEC did not or are not believed by management to have a material effect, if any, on the Company’s financial statements.
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of the Company and its direct and indirect wholly owned subsidiaries, both domestic and international. Equity investments in which we exercise significant influence but do not control and of which we are not the primary beneficiary are accounted for using the equity method. All significant inter-company and intra-company transactions and balances have been eliminated. The results of operations attributable to the non-controlling non-wholly
Use of Estimates	Use of Estimates Management uses estimates and assumptions in preparing these consolidated financial statements in accordance with U.S. GAAP. Those estimates and assumptions affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities, and the reported revenues and expenses. Actual results could vary from the estimates that were used.
Revenue Recognition and Accounts Receivable	Revenue Recognition and Accounts Receivable In accordance with Topic A.1. in SAB 13 as well as ASU 2019-09, Account receivables are based on amounts billed to customers. Management has elected to record bad debts using the direct write-off write-off
Cash and Cash Equivalents	Cash and Cash Equivalents Cash, cash equivalents and restricted cash include cash on hand and cash in banks. We also consider all highly liquid investments with a maturity of three months or less when purchased to be cash equivalents. We have $10,135 of restricted cash for collateral related to a corporate credit card program.
Long-Lived Assets	Long-Lived Assets Our policy is to recognize impairment losses relating to long-lived assets in accordance with the Accounting Standards Codification (“ASC”) topic for Property, Plant and Equipment. Decisions are based on several factors, including, but not limited to, management’s plans for future operations, recent operating results and projected cash flows. Impairment losses are included in depreciation at the time of impairment.
Property and Equipment and Depreciation	Property and Equipment and Depreciation Property and equipment is stated at historical cost. Depreciation is calculated using the straight-line method at rates based on the assets’ estimated useful lives which are normally between three and thirty years. Leasehold improvements are amortized over their estimated useful lives or lease term, if shorter. Items that may require major overhauls (such as engines or generators) that enhance or extend the useful life of vessel related assets qualify to be capitalized and depreciated over the useful life or remaining life of that asset, whichever was shorter. Certain major repair items required by industry standards to ensure a vessel’s seaworthiness also qualified to be capitalized and depreciated over the period of time until the next scheduled planned major maintenance for that item. All other repairs and maintenance were accounted for under the direct-expensing method and are expensed when incurred. The smaller vessel we received as consideration when we sold our Odyssey Explorer
Earnings Per Share	Earnings Per Share Basic earnings per share (“EPS”) is computed by dividing income available to common stockholders by the weighted-average number of common shares outstanding for the period. In periods when the Company has income, the Company would calculate basic earnings per share using the two-class Earnings Per Share. two-class two-class two-class Diluted EPS reflects the potential dilution that would occur if dilutive securities and other contracts to issue common stock were exercised or converted into common stock or resulted in the issuance of common stock that then shared in our earnings. We use the treasury stock method to compute potential common shares from stock options and warrants and the if-converted if-converted two-class At December 31, 2018, 2017 and 2016 the weighted average common shares outstanding were 8,583,795, 8,209,539 and 7,564,082, respectively. For the periods ending December 31, 2018, 2017 and 2016 in which net losses occurred, all potential common shares were excluded from Diluted EPS because the effect of including such shares would be anti-dilutive. The potential common shares, in the table following, represent potential common shares calculated using the treasury stock method from outstanding options and warrants that were excluded from the calculation of Diluted EPS: 2018 2017 2016 Average market price during the period $ 6.81 $ 3.98 $ 3.46 In the money potential common shares from options excluded 13,450 7,023 4,979 In the money potential common shares from warrants excluded 50,640 13,869 — Potential common shares from out-of-the-money Per share exercise price 2018 2017 2016 Out of the money options excluded: $ 3.59 — — 7,521 $12.48 136,833 137,666 137,666 $12.84 4,167 4,167 4,167 $26.40 75,158 75,158 75,158 $34.68 — — 73,765 $39.00 — 8,333 8,333 $41.16 — — 833 $42.00 — — 8,333 $46.80 — — 1,667 Out-of-the-money $ 3.52 — — 120,000 $ 7.16 700,000 — — $12.00 60,625 — — Total excluded 981,783 225,324 437,443 Potential common shares from outstanding Convertible Preferred Stock calculated per the if-converted 2018 2017 2016 Excluded Convertible Preferred Stock — — — The weighted average equivalent common shares relating to our unvested restricted stock awards that were excluded from potential common shares used in the earning per share calculation due to having an anti-dilutive effect are: 2018 2017 2016 Excluded unvested restricted stock awards 41,667 132,826 113,889 The following is a reconciliation of the numerators and denominators used in computing basic and diluted net income per share: 12 Month 12 Month 12 Month Net loss $ (5,172,436 ) $ (7,759,472 ) $ (6,316,021 ) Cumulative dividends on Series G Preferred Stock — — — Numerator, basic and diluted net loss available to stockholders $ (5,172,436 ) $ (7,759,472 ) $ (6,316,021 ) 12 Month 12 Month 12 Month Denominator: Shares used in computation – basic: Weighted average common shares outstanding 8,583,795 8,209,539 7,564,082 Shares used in computation – diluted: Weighted average common shares outstanding 8,583,795 8,209,539 7,564,082 Net loss per share – basic and diluted $ (0.60 ) $ (0.95 ) $ (0.84 )
Income Taxes	Income Taxes Income taxes are accounted for using an asset and liability approach that requires the recognition of deferred tax assets and liabilities for the expected future tax consequences attributable to differences between financial statement carrying amounts of existing assets and liabilities and their respective tax bases. A valuation allowance is provided when it is more likely than not that some portion or the entire deferred tax asset will not be realized.
Stock-based Compensation	Stock-based Compensation Our stock-based compensation is recorded in accordance with the guidance in the ASC topic for Stock-Based Compensation
Fair Value of Financial Instruments	Fair Value of Financial Instruments Financial instruments consist of cash, evidence of ownership in an entity, and contracts that both (i) impose on one entity a contractual obligation to deliver cash or another financial instrument to a second entity, or to exchange other financial instruments on potentially unfavorable terms with the second entity, and (ii) conveys to that second entity a contractual right (a) to receive cash or another financial instrument from the first entity, or (b) to exchange other financial instruments on potentially favorable terms with the first entity. Accordingly, our financial instruments consist of cash and cash equivalents, accounts receivable, accounts payable, accrued liabilities, derivative financial instruments and mortgage and loans payable. We carry cash and cash equivalents, accounts payable and accrued liabilities, and mortgage and loans payable at the approximate fair market value, and, accordingly, these estimates are not necessarily indicative of the amounts that we could realize in a current market exchange. We carry derivative financial instruments at fair value as is required under current accounting standards. Redeemable preferred stock has been carried at historical cost and accreted carrying values to estimated redemption values over the term of the financial instrument. Derivative financial instruments consist of financial instruments or other contracts that contain a notional amount and one or more underlying variables (e.g., interest rate, security price or other variable), require no initial net investment and permit net settlement. Derivative financial instruments may be free-standing or embedded in other financial instruments. Further, derivative financial instruments are initially, and subsequently, measured at fair value and recorded as liabilities or, in rare instances, assets. We generally do not use derivative financial instruments to hedge exposures to cash-flow, market or foreign-currency risks. However, we have entered into certain other financial instruments and contracts with features that are either (i) not afforded equity classification, (ii) embody risks not clearly and closely related to host contracts, or (iii) may be net-cash Derivatives and Hedging Fair Value Hierarchy The three levels of inputs that may be used to measure fair value are as follows: Level 1. Level 2. non-binding Level 3. non-binding non-binding
Redeemable Preferred Stock	Redeemable Preferred Stock If we issue redeemable preferred stock instruments (or any other redeemable financial instrument), they are initially evaluated for possible classification as a liability in instances where redemption is certain to occur pursuant to ASC 480 – Distinguishing Liabilities from Equity
Subsequent Events	Subsequent Events We have evaluated subsequent events for recognition or disclosure through the date this Form 10-K
Debt and Equity Securities	During 2012, we performed deep-sea Debt and Equity Securities

Organization and Summary of S_3

Organization and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2018
Reconciliation of Numerators and Denominators used in Computing Basic and Diluted Net Income Per Share	The following is a reconciliation of the numerators and denominators used in computing basic and diluted net income per share: 12 Month 12 Month 12 Month Net loss $ (5,172,436 ) $ (7,759,472 ) $ (6,316,021 ) Cumulative dividends on Series G Preferred Stock — — — Numerator, basic and diluted net loss available to stockholders $ (5,172,436 ) $ (7,759,472 ) $ (6,316,021 ) 12 Month 12 Month 12 Month Denominator: Shares used in computation – basic: Weighted average common shares outstanding 8,583,795 8,209,539 7,564,082 Shares used in computation – diluted: Weighted average common shares outstanding 8,583,795 8,209,539 7,564,082 Net loss per share – basic and diluted $ (0.60 ) $ (0.95 ) $ (0.84 )
Convertible Preferred Stock Excluded from EPS [Member]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	Potential common shares from outstanding Convertible Preferred Stock calculated per the if-converted 2018 2017 2016 Excluded Convertible Preferred Stock — — —
In the Money Potential Common Shares [Member]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The potential common shares, in the table following, represent potential common shares calculated using the treasury stock method from outstanding options and warrants that were excluded from the calculation of Diluted EPS: 2018 2017 2016 Average market price during the period $ 6.81 $ 3.98 $ 3.46 In the money potential common shares from options excluded 13,450 7,023 4,979 In the money potential common shares from warrants excluded 50,640 13,869 —
Out of Money Potential Common Shares [Member]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	Potential common shares from out-of-the-money Per share exercise price 2018 2017 2016 Out of the money options excluded: $ 3.59 — — 7,521 $12.48 136,833 137,666 137,666 $12.84 4,167 4,167 4,167 $26.40 75,158 75,158 75,158 $34.68 — — 73,765 $39.00 — 8,333 8,333 $41.16 — — 833 $42.00 — — 8,333 $46.80 — — 1,667 Out-of-the-money $ 3.52 — — 120,000 $ 7.16 700,000 — — $12.00 60,625 — — Total excluded 981,783 225,324 437,443
Unvested Restricted Stock Awards Excluded from EPS [Member]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The weighted average equivalent common shares relating to our unvested restricted stock awards that were excluded from potential common shares used in the earning per share calculation due to having an anti-dilutive effect are: 2018 2017 2016 Excluded unvested restricted stock awards 41,667 132,826 113,889

Accounts Receivable and Other_2

Accounts Receivable and Other, Net (Tables)	12 Months Ended
	Dec. 31, 2018
Receivables [Abstract]
Summary of Accounts Receivable	Our accounts receivable consisted of the following: December 31, 2018 December 31, 2017 Trade $ 9,466 $ 7,376 Related party 664,596 183,453 Other 115,359 41,551 Accounts receivable, net $ 789,421 $ 232,380

Other Current Assets (Tables)

Other Current Assets (Tables)	12 Months Ended
	Dec. 31, 2018
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Summary of Other Current Assets	Our other current assets consist of the following: December 31, December 31, Prepaid expenses $ 478,560 $ 471,686 Project deposit 532,500 — Deposits 5,076 23,841 Total other current assets $ 1,016,136 $ 495,527

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Summary of Property and Equipment	Property and equipment consist of the following: December 31, December 31, Computers and peripherals 1,021,844 1,278,461 Furniture and office equipment 1,907,116 2,625,028 Marine equipment 8,104,576 12,835,409 11,033,536 16,738,898 Less: Accumulated depreciation (10,915,557 ) (16,145,082 ) Property and equipment, net $ 117,979 $ 593,816

Other Non-Current Assets (Table

Other Non-Current Assets (Tables)	12 Months Ended
	Dec. 31, 2018
Investments, All Other Investments [Abstract]
Components of Other Long-Term Assets	Other long-term assets consist of the following: December 31, December 31, Deposits $ — $ 532,500 Total other long-term assets $ — $ 532,500

Loans Payable (Tables)

Loans Payable (Tables)	12 Months Ended
	Dec. 31, 2018
Schedule of Consolidated Notes Payable	The Company’s consolidated notes payable consisted of the following: December 31, 2018 December 31, Note 1 – Monaco 2014 $ 2,800,000 $ 2,800,000 Note 2 – Monaco 2016 1,175,000 1,138,441 Note 3 – MINOSA 1 14,750,001 14,750,001 Note 4 – Epsilon 1,000,000 1,000,000 Note 5 – SMOM 3,500,000 3,000,000 Note 6 – MINOSA 2 5,050,000 4,675,000 Note 7 – Monaco 2018 1,099,366 — Note 8 – Promissory note 74,621 — $ 29,448,988 $ 27,363,442
Summary of Fair Value of Debt	The fair value of the new debt is as follows: Monaco loans Loan one Forward cash flows: Principal $ 2,800,000 Interest 559,463 Total forward cash flows $ 3,359,463 Present value of forward cash flows $ 2,554,371 Fair value of equity conversion option 1,063,487 Fair value of debt $ 3,617,858
Summary of Debt Premium	Monaco loans Loan one Forward cash flows: Face value $ 2,800,000 Fair value 3,617,858 Difference (premium)* $ 817,858 *ASC 470-20-25-13 paid-in
Summary of Gain or Loss Upon Extinguishment Allocation	The allocation is as follows: Allocation Derivative liabilities (share purchase options) $ 1,456,825 Monaco Loan (Old Debt) 3,372,844 Monaco Loan (New Debt) (2,800,000 ) APIC (Premium) (817,858 ) Difference to APIC* $ 1,211,811 *The difference between the fair value of the new debt and the sum of the pre-modification 470-50-40-2
Schedule of Allocation of Cash Proceeds to Derivative Components at their Fair Values	The allocations of the three additional tranches were as follows. Tranche 3 Tranche 4 Tranche 5 Promissory Note $ 981,796 $ 939,935 $ 1,000,000 Beneficial Conversion Feature (“BCF”)* 18,204 60,065 — Proceeds $ 1,000,000 $ 1,000,000 $ 1,000,000
Oceanica Resources S. de. R.L [Member]
Schedule of Allocation of Cash Proceeds to Derivative Components at their Fair Values	Based on the previous conclusions, we allocated the cash proceeds first to the debt at its present value using a market rate of 15%, which is management’s estimate of a market rate loan for the Company, with the residual allocated to the Oceanica Call Option, as follows: Tranche 1 Tranche 2 Tranche 3 Tranche 4 Tranche 5 Total Promissory Note $ 1,932,759 $ 5,826,341 $ 2,924,172 $ 1,960,089 $ 1,723,492 $ 14,366,853 Deferred Income (Oceanica Call Option) 67,241 173,659 75,828 39,911 26,509 383,148 Proceeds $ 2,000,000 $ 6,000,000 $ 3,000,000 $ 2,000,000 $ 1,750,001 $ 14,750,001
Note 2 [Member] | Monaco Notes [Member]
Summary of Significant Conversion Option Valuation Inputs and Results	Significant inputs and results arising from the Binomial Lattice process are as follows for the conversion option that is classified in equity after the modification in March 2016: Underlying price on valuation date $1.25 Contractual conversion rate $1.00 Contractual term to maturity 1.82 Years Implied expected term to maturity 1.82 Years Market volatility: Range of volatilities 96.0% - 154.0% Equivalent volatilities 120.1% Risk free rates using zero coupon US Treasury Security rates 0.29% - 0.68% Equivalent market risk adjusted interest rates 0.52%

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2018
Payables and Accruals [Abstract]
Components of Accrued Expenses	Accrued expenses consist of the following: 2018 2017 Compensation and incentives $ 2,567,732 $ 1,871,071 Professional services 400,367 329,640 Interest 6,508,621 4,056,337 Accrued insurance obligations 309,826 249,247 Other operating 18,000 45,040 Total accrued expenses $ 9,804,546 $ 6,551,335

Deferred Income and Revenue P_2

Deferred Income and Revenue Participation Rights (Tables)	12 Months Ended
	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Participating Revenue Rights	The Company’s participating revenue rights and deferred revenue consisted of the following for the respective year end: December 31, 2018 December 31, 2017 “ Cambridge $ 825,000 $ 825,000 “ Seattle 62,500 62,500 Galt Resources, LLC (HMS Victory 3,756,250 3,756,250 Total revenue participation rights $ 4,643,750 $ 4,643,750

Stockholders' Equity_(Deficit)

Stockholders' Equity/(Deficit) (Tables)	12 Months Ended
	Dec. 31, 2018
Federal Home Loan Banks [Abstract]
Summary of Preferred Stock Allocated to Investors	The Purchase Agreement provides for the Company to issue and sell to the Investor shares of the Company’s preferred stock in the amounts set forth in the following table (numbers have been adjusted for the February 2016 reverse stock split): Convertible Preferred Stock Shares Price Per Share Total Investment Series AA-1 8,427,004 $ 12.00 $ 101,124,048 Series AA-2 7,223,145 $ 6.00 43,338,870 15,650,149 $ 144,462,918
Stock Options Valuation Assumptions	The assumptions used in the Black-Scholes model were as follows for stock options granted in the years ended December 31, 2018, 2017 and 2016: 2018 2017 2016 Risk-free interest rate — — 1.29 - 2.25% Expected volatility of common stock — — 80.87 - 82.69% Dividend yield — — 0% Expected life of options — — 8.2 years
Summary of Stock Option Activity	Additional information with respect to both plans stock option activity is as follows: Number of Shares Weighted Average Exercise Price Outstanding at December 31, 2015 375,283 $ 32.04 Granted 22,493 $ 2.74 Exercised — $ — Cancelled (65,361 ) $ 32.82 Outstanding at December 31, 2016 332,415 $ 21.55 Granted — $ — Exercised — $ — Cancelled (84,598 ) $ 35.59 Outstanding at December 31, 2017 247,817 $ 16.76 Granted — $ — Exercised — $ — Cancelled (9,166 ) $ 36.52 Outstanding at December 31, 2018 238,651 $ 15.95 Options exercisable at December 31, 2016 300,751 $ 22.30 Options exercisable at December 31, 2017 247,817 $ 16.76 Options exercisable at December 31, 2018 238,651 $ 15.95
Stock Options Outstanding	The following table summarizes information about stock options outstanding at December 31, 2018: Stock Options Outstanding Range of Exercise Prices Number of Shares Weighted Average Weighted Average Exercise $26.40 - $26.40 75,158 5.00 $ 26.40 $12.48 - $12.84 141,000 6.00 $ 12.48 $2.02 - $3.59 22,493 7.65 $ 2.74 238,651 5.84 $ 15.95
Estimated Fair Value of Restricted Stock Award	A summary of the status of the restricted stock awards as of December 31, 2018 and changes during the year ended December 31, 2018 is presented as follows: Number of Weighted Average Unvested at December 31, 2017 132,826 $ 5.90 Granted — $ — Vested (91,159 ) $ 3.55 Cancelled — $ — Unvested at December 31, 2018 41,667 $ 11.04
Summary of Common Stock Warrants Outstanding	The following table summarizes our common stock warrants outstanding at December 31, 2018: Common Stock Warrants Exercise Price Termination Date 120,000 $ 3.52 10/01/2021 65,625 $ 12.00 07/12/2021 700,000 7.16 11/02/2023 885,625
Summary of Analysis of Activity in CARs Balances	The following is an analysis of activity in the CARs balances as of December 31, 2018: Number of CARs Key Employee Plan Nonemployee Director Plan Unvested at December 31, 2017 229,076 — Granted 406,384 278,000 Vested (249,880 ) (278,000 ) Cancelled — — Unvested at December 31, 2018 385,580 —

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Schedule of Components of Provision for Income Tax (Benefits) are Attributable to Continuing Operations	The components of the provision for income tax (benefits) are attributable to continuing operations as follows: December 31, December 31, December 31, Current Federal $ — $ — $ — State — — — $ — $ — $ — Deferred Federal $ — $ — $ — State — — — $ — $ — $ —
Significant Components of Deferred Tax Assets and Liabilities	Significant components of the Company’s deferred tax assets and liabilities as of December 31, 2018 are as follows: Deferred tax assets: Net operating loss and tax credit carryforwards $ 48,404,432 Capital loss carryforward 147,552 Accrued expenses 559,096 Reserve for Dorado accounts receivable 287,335 Start-up 7,042 Excess of book over tax depreciation 707,044 Stock option and restricted stock award expense 1,331,067 Investment in unconsolidated entities 1,387,970 Less: valuation allowance (52,684,059 ) $ 147,479 Deferred tax liability: Property and equipment basis $ 43,155 Prepaid expenses 104,324 $ 147,479 Net deferred tax asset $ —
Schedule of Change in Valuation Allowance	The change in the valuation allowance is as follows: December 31, 2018 $ 52,684,059 December 31, 2017 49,235,133 Change in valuation allowance $ 3,448,926
Schedule of Federal and State income Tax Provision (Benefit)	The federal and state income tax provision (benefit) is summarized as follows for the years ended: December 31, December 31, December 31, Expected (benefit) $ (1,923,757 ) $ (3,718,058 ) $ (2,186,550 ) Effects of: State income taxes net of federal benefits (92,707 ) (110,667 ) (65,082 ) Nondeductible expense 29,670 711,679 (1,083,185 ) Change in valuation allowance 3,765,560 28,258,724 4,189,828 Foreign Rate Differential (1,778,766 ) (1,097,681 ) (855,011 ) Change in Deferred Taxes due to enacted changes in tax law — (24,043,997 ) — $ — $ — $ —

Quarterly Financial Data - Un_2

Quarterly Financial Data - Unaudited (Tables)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data - Unaudited	The following tables present certain unaudited consolidated quarterly financial information for each of the past eight quarters ended December 31, 2018 and 2017. This quarterly information has been prepared on the same basis as the Consolidated Financial Statements and includes all adjustments necessary to state fairly the information for the periods presented. Fiscal Year Ended December 31, 2018 Quarter Ending March 31 June 30 September 30 December 31 Revenue – net $ 511,735 $ 1,073,479 $ 886,327 $ 804,212 Gross profit 511,735 1,073,479 886,327 804,212 Net income (loss) (1,744,762 ) (641,557 ) (1,309,275 ) (1,476,842 ) Basic and diluted net income per share $ (0.21 ) $ (0.08 ) $ (0.15 ) $ (0.16 ) Fiscal Year Ended December 31, 2017 Quarter Ending March 31 June 30 September 30 December 31 Revenue – net $ 649,353 $ 587,270 $ 11,854 $ — Gross profit 649,353 587,270 11,854 — Net income (loss) (2,199,263 ) (1,916,885 ) (2,251,097 ) (1,392,227 ) Basic and diluted net income per share $ (0.28 ) $ (0.23 ) $ (0.27 ) $ (0.17 )

Organization and Summary of S_4

Organization and Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	May 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Feb. 29, 2016
Property, Plant and Equipment [Line Items]
Short-term investment maturity period		3 months
Restricted cash		$ 10,135	$ 10,010
Reverse stock split ratio		1-for-12
Capitalized cost of assets held for sale	$ 416,329	$ 4,600,000
Decrease in indebtedness	$ 650,000
Weighted average number of common shares outstanding		8,583,795	8,209,539	7,564,082
Redeemable preferred stock outstanding		0
Minimum [Member]
Property, Plant and Equipment [Line Items]
Lease term					12 months
Property and Equipment, estimated useful life		3 years
Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, estimated useful life		30 years

Organization and Summary of S_5

Organization and Summary of Significant Accounting Policies - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share for in the Money Potential Common Shares (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Average market price during the period	$ 6.81	$ 3.98	$ 3.46
Potential common shares excluded from EPS	981,783	225,324	437,443
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential common shares excluded from EPS	13,450	7,023	4,979
Warrant Derivatives [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential common shares excluded from EPS	50,640	13,869

Organization and Summary of S_6

Organization and Summary of Significant Accounting Policies - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share for Out of Money Potential Common Shares (Detail) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Out of the money options and warrants excluded	981,783	225,324	437,443
Stock Options with an Exercise Price of $3.59 per Share [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Out of the money options and warrants excluded			7,521
Stock Options With an Exercise Price of $12.48 per Share [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Out of the money options and warrants excluded	136,833	137,666	137,666
Stock Options With an Exercise Price of $12.84 per Share [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Out of the money options and warrants excluded	4,167	4,167	4,167
Stock Options With an Exercise Price of $26.40 per Share [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Out of the money options and warrants excluded	75,158	75,158	75,158
Stock Options With an Exercise Price of $34.68 per Share [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Out of the money options and warrants excluded			73,765
Stock Options With an Exercise Price of $39.00 per Share [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Out of the money options and warrants excluded		8,333	8,333
Stock Options With an Exercise Price of $41.16 per Share [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Out of the money options and warrants excluded			833
Stock Options With an Exercise Price of $42.00 per Share [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Out of the money options and warrants excluded			8,333
Stock Options With an Exercise Price of $46.80 per Share [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Out of the money options and warrants excluded			1,667
Stock Options With an Exercise Price of $3.52 per Share [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Out of the money options and warrants excluded			120,000
Stock Options With an Exercise Price of $7.16 per Share [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Out of the money options and warrants excluded	700,000
Stock Options With an Exercise Price of $12.00 per Share [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Out of the money options and warrants excluded	60,625

Organization and Summary of S_7

Organization and Summary of Significant Accounting Policies - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share for Out of Money Potential Common Shares (Parenthetical) (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stock Options with an Exercise Price of $3.59 per Share [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options exercise price per share	$ 3.59	$ 3.59	$ 3.59
Stock Options With an Exercise Price of $12.48 per Share [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options exercise price per share	12.48	12.48	12.48
Stock Options With an Exercise Price of $12.84 per Share [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options exercise price per share	12.84	12.84	12.84
Stock Options With an Exercise Price of $26.40 per Share [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options exercise price per share	26.4	26.4	26.4
Stock Options With an Exercise Price of $34.68 per Share [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options exercise price per share	34.68	34.68	34.68
Stock Options With an Exercise Price of $39.00 per Share [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options exercise price per share	39	39	39
Stock Options With an Exercise Price of $41.16 per Share [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options exercise price per share	41.16	41.16	41.16
Stock Options With an Exercise Price of $42.00 per Share [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options exercise price per share	42	42	42
Stock Options With an Exercise Price of $46.80 per Share [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options exercise price per share	46.80	46.80	46.80
Stock Options With an Exercise Price of $3.52 per Share [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options exercise price per share	3.52	3.52	3.52
Stock Options With an Exercise Price of $7.16 per Share [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options exercise price per share	7.16	7.16	7.16
Stock Options With an Exercise Price of $12.00 per Share [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options exercise price per share	$ 12	$ 12	$ 12

Organization and Summary of S_8

Organization and Summary of Significant Accounting Policies - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share, Convertible Preferred Stock (Detail) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential common shares excluded from EPS	981,783	225,324	437,443
Convertible Preferred Stock Excluded from EPS [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential common shares excluded from EPS	0	0	0

Organization and Summary of S_9

Organization and Summary of Significant Accounting Policies - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share, Unvested Restricted Stock Awards (Detail) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Excluded unvested restricted stock awards	981,783	225,324	437,443
Unvested Restricted Stock Awards Excluded from EPS [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Excluded unvested restricted stock awards	41,667	132,826	113,889

Organization and Summary of _10

Organization and Summary of Significant Accounting Policies - Reconciliation of Numerators and Denominators used in Computing Basic and Diluted Net Income Per Share (Detail) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Net loss									$ (5,172,436)	$ (7,759,472)	$ (6,316,021)
Cumulative dividends on Series G Preferred Stock									0	0	0
Numerator, basic and diluted net loss available to stockholders									$ (5,172,436)	$ (7,759,472)	$ (6,316,021)
Shares used in computation - basic:
Weighted average common shares outstanding									8,583,795	8,209,539	7,564,082
Shares used in computation - diluted:
Weighted average common shares outstanding									8,583,795	8,209,539	7,564,082
Net loss per share - basic and diluted	$ (0.16)	$ (0.15)	$ (0.08)	$ (0.21)	$ (0.17)	$ (0.27)	$ (0.23)	$ (0.28)	$ (0.60)	$ (0.95)	$ (0.84)

Concentration of Credit Risk -

Concentration of Credit Risk - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2018USD ($)Institution	Dec. 31, 2017USD ($)
Debt Disclosure [Abstract]
Uninsured cash balance	$ 2,600,000	$ 800,000
Number of financial institutions in which cash is deposited | Institution	1
Amount of loan outstanding with variable interest rate	$ 0

Accounts Receivable and Other_3

Accounts Receivable and Other, Net - Summary of Accounts Receivable (Detail) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable, net	$ 789,421	$ 232,380
Trade [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, gross	9,466	7,376
Related Party [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, gross	664,596	183,453
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, gross	$ 115,359	$ 41,551

Accounts Receivable and Other_4

Accounts Receivable and Other, Net - Additional Information (Detail) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Related Party [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	$ 664,596	$ 183,453
Neptune Minerals, Inc. [Member] | Related Party [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	612,498	183,453
Deep Sea Mineral Exploration Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	$ 52,098	$ 0

Other Current Assets - Summary

Other Current Assets - Summary of Other Current Assets (Detail) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid expenses	$ 478,560	$ 471,686
Project deposit	532,500
Deposits	5,076	23,841
Total other current assets	$ 1,016,136	$ 495,527

Other Current Assets - Addition

Other Current Assets - Additional Information (Detail) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Other Assets Current [Line Items]
Prepaid expenses	$ 478,560	$ 471,686
Directors and Officers Insurance [Member]
Other Assets Current [Line Items]
Prepaid expenses	388,137	316,795
Marine Insurance [Member]
Other Assets Current [Line Items]
Prepaid expenses	40,119	67,447
Professional Services [Member]
Other Assets Current [Line Items]
Prepaid expenses	38,674	75,784
Other Insurances [Member]
Other Assets Current [Line Items]
Prepaid expenses	$ 11,630	$ 11,660

Property and Equipment - Summar

Property and Equipment - Summary of Property and Equipment (Detail) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 11,033,536	$ 16,738,898
Less: Accumulated depreciation	(10,915,557)	(16,145,082)
Total property and equipment	117,979	593,816
Computers and Peripherals [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,021,844	1,278,461
Furniture and Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,907,116	2,625,028
Marine Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 8,104,576	$ 12,835,409

Property and Equipment - Additi

Property and Equipment - Additional Information (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	May 31, 2017
Property, Plant and Equipment [Line Items]
Vessel assets sold and consideration received		$ 100,000
Capitalized cost of assets held for sale		4,600,000			$ 416,329
Proceeds from sale of property and equipment		1,000,000
Gain on sale of equipment		897,664	$ 289,328	$ 992,595
Gain on sale of marine assets		897,664	289,328	992,595
Cash proceeds from sale of vessel		$ 1,003,662	80,000	200,000
Non Cash [Member]
Property, Plant and Equipment [Line Items]
Gain on sale of equipment				792,595
Gain on sale of marine assets				$ 792,595
Note 2 [Member]
Property, Plant and Equipment [Line Items]
Loans payable, repayment	$ 650,000		650,000
Marine Vessel [Member]
Property, Plant and Equipment [Line Items]
Cash proceeds from sale of vessel	$ 650,000		$ 650,000

Other Non-Current Assets - Comp

Other Non-Current Assets - Components of Other Long-Term Assets (Detail)	Dec. 31, 2017USD ($)
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deposits	$ 532,500
Total other long-term assets	$ 532,500

Other Non-Current Assets - Addi

Other Non-Current Assets - Additional Information (Detail) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Other Long Term Assets [Line Items]
Deposits for conservation and documentation of artifacts		$ 100,000
Deposits		532,500
UNITED KINGDOM
Other Long Term Assets [Line Items]
Deposits with United Kingdom's Ministry of Defense		$ 432,500
Return of deposits with United Kingdom's Ministry of Defense	$ 588,965

Investment in Unconsolidated _2

Investment in Unconsolidated Entity - Additional Information (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2012
Schedule of Equity Method Investments [Line Items]
Investment carrying value		$ 752,667
Greg Stemm [Member]
Schedule of Equity Method Investments [Line Items]
Investment carrying value		$ 752,667
Chatham Rock Phosphate, Ltd. [Member]
Schedule of Equity Method Investments [Line Items]
Investment carrying value			$ 0
Deep sea mining exploratory services			$ 1,680,000
Shares received from CRP	141,884		9,320,348
Outstanding equity stake in CRP	1.00%
Neptune Minerals, Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Ownership percentage		14.00%
Investment carrying value		$ 0
Neptune Minerals, Inc. [Member] | Common Class A [Member]
Schedule of Equity Method Investments [Line Items]
Shares owned		0
Neptune Minerals, Inc. [Member] | Common Class B Non Voting Shares [Member]
Schedule of Equity Method Investments [Line Items]
Current investment position in NMI		3,092,488
Aggregate number of shares converted		261,200
Neptune Minerals, Inc. [Member] | Series A Preferred Non Voting Shares [Member]
Schedule of Equity Method Investments [Line Items]
Current investment position in NMI		2,612
Dorado Ocean Resources, Ltd. [Member]
Schedule of Equity Method Investments [Line Items]
Loss from unconsolidated entity		$ 21,300,000

Loans Payable - Schedule of Con

Loans Payable - Schedule of Consolidated Notes Payable (Detail) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Loans payable	$ 29,448,988	$ 27,363,442
Loans Payable [Member] | Note 1- Monaco 2014 [Member]
Debt Instrument [Line Items]
Loans payable	2,800,000	2,800,000
Loans Payable [Member] | Note 2 - Monaco 2016 [Member]
Debt Instrument [Line Items]
Loans payable	1,175,000	1,138,441
Loans Payable [Member] | Note 3 - MINOSA 1 [Member]
Debt Instrument [Line Items]
Loans payable	14,750,001	14,750,001
Loans Payable [Member] | Note 4 - Epsilon [Member]
Debt Instrument [Line Items]
Loans payable	1,000,000	1,000,000
Loans Payable [Member] | Note 5 - SMOM [Member]
Debt Instrument [Line Items]
Loans payable	3,500,000	3,000,000
Loans Payable [Member] | Note 6 - MINOSA 2 [Member]
Debt Instrument [Line Items]
Loans payable	5,050,000	$ 4,675,000
Loans Payable [Member] | Note 7 - Monaco 2018 [Member]
Debt Instrument [Line Items]
Loans payable	1,099,366
Loans Payable [Member] | Note 8 - Promissory note [Member]
Debt Instrument [Line Items]
Loans payable	$ 74,621

Loans Payable - Note 1 - Monaco

Loans Payable - Note 1 - Monaco 2014 - Additional Information (Detail) - USD ($)	Dec. 10, 2015	Aug. 14, 2014	Mar. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Apr. 01, 2018	Dec. 01, 2014	Oct. 01, 2014
Note 1- Monaco 2014 [Member]
Debt Instrument [Line Items]
Aggregate amount issuable		$ 10,000,000
Interest rate, stated percentage		11.00%
Extinguishment of debt, amount	$ 2,200,000
Notes ceased to bear interest, amount	$ 5,000,000
Debt instrument maturity date	Dec. 31, 2017		Apr. 1, 2018
Accrued interest				$ 507,741	$ 308,800
Outstanding notes balance				2,800,000	2,800,000
Note 1- Monaco 2014 [Member] | Oceanica Resources S. de. R.L [Member]
Debt Instrument [Line Items]
Per share value of shares exercised by private investor		$ 3.15
Aggregate value of shares issued to lender		$ 1,000,000
Note 1- Monaco 2014 [Member] | Oceanica Resources S. de. R.L [Member] | Loan Modification March Two Thousand Sixteen [Member]
Debt Instrument [Line Items]
Per share value of shares exercised by private investor			$ 1
Note 1- Monaco 2014 [Member] | First Tranche [Member]
Debt Instrument [Line Items]
Loan amount borrowed		$ 5,000,000
Note 1- Monaco 2014 [Member] | Second Tranche [Member]
Debt Instrument [Line Items]
Loan amount borrowed								$ 2,500,000
Note 1- Monaco 2014 [Member] | Third Tranche [Member]
Debt Instrument [Line Items]
Loan amount borrowed							$ 2,500,000
Note 2 [Member]
Debt Instrument [Line Items]
Aggregate amount issuable			$ 1,825,000	1,825,000
Interest rate, stated percentage			10.00%
Debt instrument maturity date			Apr. 15, 2018
Accrued interest				224,846	$ 134,527
Debt default interest rate						18.00%
Outstanding notes balance				$ 1,175,000

Loans Payable - Note 2 - Monaco

Loans Payable - Note 2 - Monaco 2016 - Additional Information (Detail)	Dec. 10, 2015USD ($)	Mar. 31, 2018USD ($)	Mar. 31, 2016USD ($)Installment$ / shares	Mar. 31, 2018USD ($)	Jun. 30, 2017USD ($)	Dec. 31, 2018USD ($)$ / sharesshares	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Debt Instrument [Line Items]
Cash proceeds from sale of vessel						$ 1,003,662	$ 80,000	$ 200,000
Loans payable						$ 29,448,988	27,363,442
Marine Vessel [Member]
Debt Instrument [Line Items]
Cash proceeds from sale of vessel					$ 650,000		650,000
Monaco [Member]
Debt Instrument [Line Items]
Debt instrument, value of shares				$ 1,000,000
Loan Modification [Member]
Debt Instrument [Line Items]
Conversion price of Notes | $ / shares						$ 1
Loans payable						$ 2,800,000
Loan Modification [Member] | First Tranche [Member]
Debt Instrument [Line Items]
Convertible notes payable	$ 5,000,000
Agreement description						Monaco agreed to cease interest as of December 10, 2015 and reduce the loan balance by (i) the cash or other value received from the SS Central Americashipwreck project ("SSCA") or (ii) if the proceeds received from the SSCA project were insufficient to pay off the loan balance by December 31, 2017, then Monaco could seek repayment of the remaining outstanding balance on the loan by withholding Odyssey's 21.25% "additional consideration" in new shipwreck projects performed for Monaco in the future.
Additional consideration percentage	21.25%
Loan Modification [Member] | Second Tranche [Member]
Debt Instrument [Line Items]
Aggregate amount issuable	$ 300,000
Debt instrument maturity date	Dec. 31, 2017
Convertible notes payable	$ 2,500,000
Reduced principal amount	$ 2,200,000
Loan Modification [Member] | Third Tranche [Member]
Debt Instrument [Line Items]
Debt instrument maturity date	Dec. 31, 2017
Convertible notes payable	$ 2,500,000
Loan Modification [Member] | Oceanica Resources S. de. R.L [Member]
Debt Instrument [Line Items]
Debt instrument maturity date						Dec. 31, 2017
Equity component in loans payable						$ 3,174,603
Debt instrument, number of shares | shares						3,174,603
Debt instrument, value of shares						$ 3,174,603
Loan Modification [Member] | Monaco [Member]
Debt Instrument [Line Items]
Number of options eliminated under share purchase option | shares						3,174,603
Per share value of shares purchased by private investor | $ / shares						$ 3.15
Note 2 [Member]
Debt Instrument [Line Items]
Aggregate amount issuable			$ 1,825,000			$ 1,825,000
Interest rate, stated percentage			10.00%
Debt instrument maturity date			Apr. 15, 2018
Outstanding notes balance						1,175,000
Loans payable, repayment					$ 650,000		650,000
BCF amount recorded		$ 456,250
Interest expense related to discount						0	252,940
Accrued interest						$ 224,846	$ 134,527
Note 2 [Member] | Oceanica Resources S. de. R.L [Member]
Debt Instrument [Line Items]
Conversion price of Notes | $ / shares			$ 1
Note 2 [Member] | Exploraciones Oceanicas [Member]
Debt Instrument [Line Items]
Aggregate amount issuable			$ 18,000,000
Debt instrument maturity date			Sep. 25, 2015
Note 2 [Member] | Oceanica Marine Operations [Member]
Debt Instrument [Line Items]
Aggregate amount issuable			$ 9,300,000
Debt instrument term			30 days
Aggregate consideration payable			$ 1,800,000
Debt instrument number of installments | Installment			10
Installment amount of Notes			$ 750,000
Equipment carrying value			$ 300,000

Loans Payable - Summary of Fair

Loans Payable - Summary of Fair Value of Debt (Detail) - USD ($)	Dec. 31, 2018	Mar. 31, 2016
Note 2 [Member]
Forward cash flows:
Principal	$ 1,825,000	$ 1,825,000
Monaco Notes [Member]
Forward cash flows:
Principal	2,800,000
Monaco Notes [Member] | Note 2 [Member]
Forward cash flows:
Principal	2,800,000
Interest	559,463
Total forward cash flows	3,359,463
Present value of forward cash flows	2,554,371
Fair value of equity conversion option	1,063,487
Fair value of debt	$ 3,617,858

Loans Payable - Summary of Sign

Loans Payable - Summary of Significant Conversion Option Valuation Inputs and Results (Detail) - After Modification [Member] - Binomial Lattice Process [Member]	9 Months Ended
	Sep. 30, 2018$ / shares
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Underlying price on valuation date	$ 1.25
Contractual conversion rate	$ 1
Contractual term to maturity	1 year 9 months 25 days
Implied expected term to maturity	1 year 9 months 25 days
Market volatility:
Equivalent market risk adjusted interest rates	0.52%
Measurement Input, Price Volatility [Member]
Market volatility:
Equivalent volatilities/Risk free rates using zero coupon US Treasury Security rates	1.201
Minimum [Member] | Measurement Input, Price Volatility [Member]
Market volatility:
Equivalent volatilities/Risk free rates using zero coupon US Treasury Security rates	0.960
Minimum [Member] | Measurement Input, Risk Free Interest Rate [Member]
Market volatility:
Equivalent volatilities/Risk free rates using zero coupon US Treasury Security rates	0.0029
Maximum [Member] | Measurement Input, Price Volatility [Member]
Market volatility:
Equivalent volatilities/Risk free rates using zero coupon US Treasury Security rates	1.540
Maximum [Member] | Measurement Input, Risk Free Interest Rate [Member]
Market volatility:
Equivalent volatilities/Risk free rates using zero coupon US Treasury Security rates	0.68

Loans Payable - Summary of Debt

Loans Payable - Summary of Debt Premium (Detail) - USD ($)	Dec. 31, 2018	Mar. 31, 2016
Monaco Notes [Member]
Forward cash flows:
Face value	$ 2,800,000
Note 2 [Member]
Forward cash flows:
Face value	1,825,000	$ 1,825,000
Note 2 [Member] | Monaco Notes [Member]
Forward cash flows:
Face value	2,800,000
Fair value of debt	3,617,858
Difference (premium)	$ 817,858

Loans Payable - Summary of De_2

Loans Payable - Summary of Debt Premium (Parenthetical) (Detail) - Monaco Notes [Member]	Dec. 31, 2018USD ($)
Debt Instrument [Line Items]
Face value	$ 2,800,000
Paid-in Capital [Member]
Debt Instrument [Line Items]
Debt premium recorded to additional paid-in capital	$ 817,858

Loans Payable - Summary of Gain

Loans Payable - Summary of Gain or Loss Upon Extinguishment Allocation (Detail) - Note 2 - Monaco 2016 [Member]	12 Months Ended
	Dec. 31, 2018USD ($)
Extinguishment of Debt [Line Items]
Difference to APIC	$ 1,211,811
Derivative Liabilities (Share Purchase Options) [Member]
Extinguishment of Debt [Line Items]
Difference to APIC	1,456,825
Monaco Loan (Old Debt) [Member]
Extinguishment of Debt [Line Items]
Difference to APIC	3,372,844
Monaco Loan (New Debt) [Member]
Extinguishment of Debt [Line Items]
Difference to APIC	(2,800,000)
Paid-in Capital [Member] | Premium [Member]
Extinguishment of Debt [Line Items]
Difference to APIC	$ (817,858)

Loans Payable - Note 3 - MINOSA

Loans Payable - Note 3 - MINOSA - Additional Information (Detail)	4 Months Ended	12 Months Ended
	Jun. 30, 2015Tranches	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Mar. 11, 2015USD ($)
Oceanica Call Option [Member] | Oceanica Resources S. de. R.L [Member]
Debt Instrument [Line Items]
Derivative, fixed value		$ 40,000,000
Promissory Note [Member] | Oceanica Resources S. de. R.L [Member]
Debt Instrument [Line Items]
Promissory note outstanding amount		14,750,001
Promissory Note [Member] | Deferred Income Call Option [Member] | Oceanica Resources S. de. R.L [Member]
Debt Instrument [Line Items]
Promissory note outstanding amount		383,148
Debt discount amount		$ 383,148
Note 6 - MINOSA 2 [Member]
Debt Instrument [Line Items]
Debt instrument, threshold payment term		60 days	60 days
Stock Purchase Agreement [Member] | Note 6 - MINOSA 2 [Member] | Promissory Note [Member]
Debt Instrument [Line Items]
Promissory note face amount				$ 14,750,000
MINOSA [Member]
Debt Instrument [Line Items]
Debt, interest expense		$ 1,180,000	$ 1,180,000
MINOSA [Member] | Promissory Note [Member]
Debt Instrument [Line Items]
Estimated market rate loan percentage		15.00%
MINOSA [Member] | Stock Purchase Agreement [Member] | Oceanica Call Option [Member] | Oceanica Resources S. de. R.L [Member]
Debt Instrument [Line Items]
Share purchase agreement expiration date		Mar. 30, 2016
Stock granted during period, value		$ 40,000,000
Stock granted during period, percentage		54.00%
Call option expiration date		Mar. 11, 2016
MINOSA [Member] | Stock Purchase Agreement [Member] | Promissory Note [Member]
Debt Instrument [Line Items]
Interest rate, stated percentage		8.00%
Promissory note outstanding amount		$ 14,750,000
Debt instrument maturity date		Mar. 18, 2017
Promissory note face amount				$ 14,750,000
Number of advances | Tranches	5

Loans Payable - Schedule of All

Loans Payable - Schedule of Allocation of Cash Proceeds to Derivative Components at their Fair Values - Promissory Note (Detail) - Promissory Note [Member] - Oceanica Resources S. de. R.L [Member]	Dec. 31, 2018USD ($)
Debt Instrument [Line Items]
Cash proceeds	$ 14,750,001
Deferred Income Call Option [Member]
Debt Instrument [Line Items]
Cash proceeds	383,148
2014 Convertible Promissory Notes [Member]
Debt Instrument [Line Items]
Cash proceeds	14,366,853
First Tranche [Member]
Debt Instrument [Line Items]
Cash proceeds	2,000,000
First Tranche [Member] | Deferred Income Call Option [Member]
Debt Instrument [Line Items]
Cash proceeds	67,241
First Tranche [Member] | 2014 Convertible Promissory Notes [Member]
Debt Instrument [Line Items]
Cash proceeds	1,932,759
Second Tranche [Member]
Debt Instrument [Line Items]
Cash proceeds	6,000,000
Second Tranche [Member] | Deferred Income Call Option [Member]
Debt Instrument [Line Items]
Cash proceeds	173,659
Second Tranche [Member] | 2014 Convertible Promissory Notes [Member]
Debt Instrument [Line Items]
Cash proceeds	5,826,341
Third Tranche [Member]
Debt Instrument [Line Items]
Cash proceeds	3,000,000
Third Tranche [Member] | Deferred Income Call Option [Member]
Debt Instrument [Line Items]
Cash proceeds	75,828
Third Tranche [Member] | 2014 Convertible Promissory Notes [Member]
Debt Instrument [Line Items]
Cash proceeds	2,924,172
Fourth Tranche [Member]
Debt Instrument [Line Items]
Cash proceeds	2,000,000
Fourth Tranche [Member] | Deferred Income Call Option [Member]
Debt Instrument [Line Items]
Cash proceeds	39,911
Fourth Tranche [Member] | 2014 Convertible Promissory Notes [Member]
Debt Instrument [Line Items]
Cash proceeds	1,960,089
Fifth Tranche [Member]
Debt Instrument [Line Items]
Cash proceeds	1,750,001
Fifth Tranche [Member] | Deferred Income Call Option [Member]
Debt Instrument [Line Items]
Cash proceeds	26,509
Fifth Tranche [Member] | 2014 Convertible Promissory Notes [Member]
Debt Instrument [Line Items]
Cash proceeds	$ 1,723,492

Loans Payable - Note 4 - Epsilo

Loans Payable - Note 4 - Epsilon - Additional Information (Detail) $ / shares in Units, Cuota in Millions

Aug. 10, 2017USD ($)

Mar. 21, 2017USD ($)shares

Dec. 15, 2016$ / sharesshares

Nov. 15, 2016$ / sharesshares

Oct. 16, 2016$ / sharesshares

Oct. 01, 2016USD ($)d$ / sharesshares

Mar. 18, 2016USD ($)dCuota$ / shares

Apr. 30, 2017USD ($)$ / sharesshares

Jun. 30, 2017USD ($)shares

Dec. 31, 2018USD ($)Cuotashares

Dec. 31, 2017USD ($)

Dec. 31, 2016USD ($)

Mar. 18, 2017USD ($)

Debt Instrument [Line Items]

Aggregate fair value of warrants

$ 303,712

Epsilon Acquisitions, LLC [Member]

Debt Instrument [Line Items]

Aggregate amount issuable

$ 6,000,000

Accrued interest

$ 99,998

$ 299,294

Aggregate fair value of warrants

303,712

Inducement expense

303,712

Notes Payable, Other Payables [Member] | Third Tranche [Member]

Debt Instrument [Line Items]

Conversion price of Notes | $ / shares

$ 3.52

Conversion of stock, shares Issued | shares

1,000,000

Notes Payable, Other Payables [Member] | Fourth Tranche [Member]

Debt Instrument [Line Items]

Conversion price of Notes | $ / shares

$ 4.19

Conversion of stock, shares Issued | shares

1,000,000

Notes Payable, Other Payables [Member] | Fifth Tranche [Member]

Debt Instrument [Line Items]

Conversion price of Notes | $ / shares

$ 4.13

Conversion of stock, shares Issued | shares

1,000,000

Notes Payable, Other Payables [Member] | MINOSA [Member]

Debt Instrument [Line Items]

Aggregate amount issuable

14,750,000

Debt Instrument, acceleration clause description

The indebtedness may be accelerated upon the occurrence of specified events of default including (a) OME’s failure to pay any amount payable on the date due and payable; (b) OME or we fail to perform or observe any term, covenant, or agreement in the Purchase Agreement or the related documents, subject to a five-day cure period; (c) an event of default or material breach by OME, us or any of our affiliates under any of the other loan documents shall have occurred and all grace periods, if any, applicable thereto shall have expired; (d) the Stock Purchase Agreement shall have been terminated; (e) specified dissolution, liquidation, insolvency, bankruptcy, reorganization, or similar cases or actions are commenced by or against OME or any of its subsidiaries, in specified circumstances unless dismissed or stayed within 60 days; (f) the entry of judgment or award against OME or any of its subsidiaries in excess or $100,000; and (g) a change in control (as defined in the Purchase Agreement) occurs

Judgment amount for acceleration of indebtedness

100,000

Notes Payable, Other Payables [Member] | Epsilon Acquisitions, LLC [Member]

Debt Instrument [Line Items]

Aggregate amount issuable

$ 6,000,000

$ 3,000,000

3,000,000

$ 3,000,000

Installment amount of Notes

$ 1,500,000

Interest rate, stated percentage

10.00%

10.00%

Notes security description

We granted security interests to Epsilon in (a) the 54 million cuotas (a unit of ownership under Panamanian law) of Oceanica Resources S. de R.L. ("Oceanica") held by our wholly owned subsidiary, Odyssey Marine Enterprises, Ltd. ("OME"), (b) all notes and other receivables from Oceanica and its subsidiary owed to the Odyssey Pledgors, and (c) all of the outstanding equity in OME.

Conversion price of Notes | $ / shares

$ 5

$ 5

$ 3.3

Conversion price of Notes upon default | $ / shares

$ 2.50

Debt instrument maturity date

Mar. 18, 2017

Mar. 18, 2017

Pledged units of ownership | Cuota

54

54

Number of trading days | d

75

75

Lender's out of pocket costs

$ 50,000

Accrued interest

$ 5,000,000

$ 302,274

Conversion of stock, shares Issued | shares

670,455

670,455

670,455

670,455

Beneficial conversion feature recorded

$ 96,000

Debt conversion amount

$ 2,000,000

$ 2,000,000

Common stock purchase warrant | shares

120,000

Warrant right exercise price | $ / shares

$ 3.52

Warrant Expiration Date

Oct. 1, 2021

Warrant right exercise price description

Warrant shall be the number determined by multiplying 120,000 by a fraction, (a) the numerator of which is the aggregate principal amount of advances that have been extended to the OME by Epsilon pursuant to the Restated Note Purchase Agreement on or after the date of the Warrant and prior to the date of such failure and (b) the denominator of which is $3.0 million.

Equity component in loans payable

$ 3,000,000

$ 3,000,000

Amount of loan outstanding

2,000,000

1,000,000

Notes Payable, Other Payables [Member] | Epsilon Acquisitions, LLC [Member] | Maximum [Member]

Debt Instrument [Line Items]

Aggregate amount issuable

$ 6,050,000

Notes Payable, Other Payables [Member] | Epsilon Acquisitions, LLC [Member] | Maximum [Member] | Tranche [Member]

Debt Instrument [Line Items]

Accrued interest

$ 302,274

Conversion of stock, shares Issued | shares

1,388,769

Loans Payable - Schedule of A_2

Loans Payable - Schedule of Allocation of Cash Proceeds to Derivative Components at their Fair Values - Additional Tranches (Detail) - Promissory Note [Member] - Epsilon Acquisitions, LLC [Member]	Dec. 31, 2018USD ($)
Third Tranche [Member]
Debt Instrument [Line Items]
Cash proceeds	$ 1,000,000
Third Tranche [Member] | Beneficial Conversion Feature ("BCF") [Member]
Debt Instrument [Line Items]
Cash proceeds	18,204
Third Tranche [Member] | 2014 Convertible Promissory Notes [Member]
Debt Instrument [Line Items]
Cash proceeds	981,796
Fourth Tranche [Member]
Debt Instrument [Line Items]
Cash proceeds	1,000,000
Fourth Tranche [Member] | Beneficial Conversion Feature ("BCF") [Member]
Debt Instrument [Line Items]
Cash proceeds	60,065
Fourth Tranche [Member] | 2014 Convertible Promissory Notes [Member]
Debt Instrument [Line Items]
Cash proceeds	939,935
Fifth Tranche [Member]
Debt Instrument [Line Items]
Cash proceeds	1,000,000
Fifth Tranche [Member] | 2014 Convertible Promissory Notes [Member]
Debt Instrument [Line Items]
Cash proceeds	$ 1,000,000

Loans Payable - Note 5 - SMOM -

Loans Payable - Note 5 - SMOM - Additional Information (Detail) - Note 5 - SMOM [Member] - USD ($)	May 03, 2017	Dec. 31, 2018	Dec. 31, 2017	Apr. 20, 2018
Debt Instrument [Line Items]
Aggregate amount issuable	$ 3,000,000			$ 3,500,000
Interest rate, stated percentage	10.00%
Annual Principal Payment	$ 500,000
Loan balance		$ 3,500,000
Accrued interest		330,822	$ 204,863
Maximum [Member]
Debt Instrument [Line Items]
Convertible debt		$ 2,000,000
Neptune Minerals, Inc. [Member]
Debt Instrument [Line Items]
Accounts receivable assigned for loan	50.00%
Accounts receivable, gross	$ 0
Aldama Mining Company, S.de R.L. de C.V [Member]
Debt Instrument [Line Items]
Percentage of equity interest	10.00%
Value of equity interest	$ 1,000,000
Aldama Mining Company, S.de R.L. de C.V [Member] | Maximum [Member]
Debt Instrument [Line Items]
Percentage of equity interest	50.00%

Loans Payable - Note 6 - MINOSA

Loans Payable - Note 6 - MINOSA 2 - Additional Information (Detail) $ / shares in Units, Cuota in Millions	Aug. 10, 2017USD ($)d$ / shares	Oct. 01, 2016USD ($)d$ / shares	Mar. 18, 2016USD ($)dCuota$ / shares	Apr. 30, 2017USD ($)$ / shares	Jun. 30, 2017USD ($)	Dec. 31, 2018USD ($)Cuota	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Mar. 21, 2017USD ($)	Mar. 18, 2017USD ($)	Mar. 11, 2015USD ($)
Note 6 - MINOSA 2 [Member]
Debt Instrument [Line Items]
Accrued interest						$ 504,075	$ 142,110
Minosa Purchase Agreement [Member] | Loans Payable [Member]
Debt Instrument [Line Items]
Debt , maximum borrowing capacity	$ 3,000,000
Amount of loan outstanding	2,700,000
Epsilon Acquisitions, LLC [Member]
Debt Instrument [Line Items]
Accrued interest							99,998	$ 299,294
Aggregate amount issuable			$ 6,000,000
Epsilon Acquisitions, LLC [Member] | Notes Payable, Other Payables [Member]
Debt Instrument [Line Items]
Amount of loan outstanding						1,000,000			$ 2,000,000
Debt conversion amount	$ 2,000,000						$ 2,000,000
Interest rate, stated percentage		10.00%	10.00%
Number of trading days | d		75	75
Conversion price of Notes | $ / shares		$ 5	$ 5	$ 3.3
BCF amount recorded						96,000
Accrued interest				$ 5,000,000	$ 302,274
Aggregate amount issuable		$ 3,000,000	$ 3,000,000						6,000,000	$ 3,000,000
Debt conversion into equity						$ 3,000,000			$ 3,000,000
Pledged units of ownership | Cuota			54			54
Epsilon Acquisitions, LLC [Member] | Second AR Epsilon Note [Member]
Debt Instrument [Line Items]
Amount of loan outstanding						$ 1,000,000
Note 6 - MINOSA 2 [Member]
Debt Instrument [Line Items]
Debt instrument, threshold payment term						60 days	60 days
BCF amount recorded						$ 62,925
Debt Instrument, acceleration clause description						The obligations under the Minosa Note may be accelerated upon the occurrence of specified events of default including (a) our failure to pay any amount payable under the Minosa Note on the date due and payable; (b) our failure to perform or observe any term, covenant, or agreement in the Minosa Note or the related documents, subject to a five-day cure period; (c) the occurrence and expiration of all applicable grace periods, if any, of an event of default or material breach by us under any of the other loan documents; (d) the termination of the SPA; (e) commencement of certain specified dissolution, liquidation, insolvency, bankruptcy, reorganization, or similar cases or actions by or against us, in specified circumstances unless dismissed or stayed within 60 days; (f) the entry of a judgment or award against us in excess of $100,000; and (g) the occurrence of a change in control (as defined in the Minosa Note).
Judgment amount for acceleration of indebtedness						$ 100,000
Minimum aggregate offering price						$ 3,000,000
Note 6 - MINOSA 2 [Member] | Stock Purchase Agreement [Member] | Promissory Note [Member]
Debt Instrument [Line Items]
Aggregate amount issuable											$ 14,750,000
Note 6 - MINOSA 2 [Member] | Loans Payable [Member]
Debt Instrument [Line Items]
Amount of loan outstanding							$ 5,050,000
Interest rate, stated percentage	10.00%
Debt instrument, threshold payment term	60 days
Number of trading days | d	75
Conversion price of Notes | $ / shares	$ 4.41
Note 6 - MINOSA 2 [Member] | Notes Payable, Other Payables [Member]
Debt Instrument [Line Items]
Amount of loan outstanding		$ 2,000,000

Loans Payable - Note 7 - Monaco

Loans Payable - Note 7 - Monaco 2018 - Additional Information (Detail) - Note 7 - Monaco 2018 [Member] - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Mar. 31, 2018
Debt Instrument [Line Items]
Loan amount borrowed			$ 1,000,000
Interest rate, stated percentage			10.00%
Agreement description	During the period ended March 31, 2018, Monaco advanced us $1.0 million that was applied to a loan agreement that was executed on April 20, 2018. Monaco also agreed to treat $99,366 of back rent owed by us to Monaco as part of this loan resulting in an aggregate principal amount of $1,099,366 at September 30, 2018. The indebtedness bears interest at 10.0% percent per year. All principal and any unpaid interest is to be payable on the first anniversary of this agreement, April 20, 2019. This debt is secured by cash proceeds, if any, from our future shipwreck projects we have contracted with Magellan. As additional consideration, their share purchase option expiration date, as discussed in Note 1 – Monaco 2014 and Note 2 – Monaco 2016 above, has been extended from 30 days to seven months after the note becomes paid in full. For the three-months ended September 30, 2018, interest expense in the amount of $28,498 was recorded.
Back rent considered as part of loan			$ 99,366
Aggregate amount issuable	$ 1,099,366
Accrued interest	$ 79,539	$ 0

Loans Payable - Note 8 - Promis

Loans Payable - Note 8 - Promissory Note - Additional Information (Detail) - Note And Warrant Purchase Agreement [Member]	Jul. 12, 2018USD ($)Parties	Dec. 31, 2018USD ($)$ / sharesshares	Dec. 31, 2017USD ($)	Oct. 04, 2018USD ($)	Aug. 17, 2018USD ($)
Debt Instrument [Line Items]
Debt instrument face amount	$ 1,050,000
Number of individuals purchase agreement entered into | Parties	2
Debt instrument interest rate	8.00%
Debt instrument conversion rate after sale of additional notes or date of closing		8
Transfer of indebtedness after sale of additional notes or date of closing		$ 500,000
Warrants exercised to purchase common shares | shares		50,000
Warrants exercise price | $ / shares		$ 12
Accrued interest		$ 33,284	$ 0
Beneficial Conversion Feature ("BCF") [Member]
Debt Instrument [Line Items]
Debt instrument face amount		1,050,000
Debt, interest expense		74,621
Book value of debt		74,621
Maximum [Member] | Beneficial Conversion Feature ("BCF") [Member]
Debt Instrument [Line Items]
Cash proceeds from issuance of debt		$ 1,050,000
Aldama Mining Company, S.de R.L. de C.V [Member]
Debt Instrument [Line Items]
Ownership interest in subsidiaries the note to be converted after sale of additional notes or date of closing		7.50%
Debt Instrument, Redemption, Period One [Member]
Debt Instrument [Line Items]
Debt instrument face amount	$ 500,000
Debt Instrument, Redemption, Period Two [Member]
Debt Instrument [Line Items]
Debt instrument face amount					$ 300,000
Debt Instrument, Redemption, Period Three [Member]
Debt Instrument [Line Items]
Debt instrument face amount				$ 250,000
Individual One [Member] | Minimum [Member]
Debt Instrument [Line Items]
Ownership percentage in company's common stock	5.00%

Accrued Expenses - Components o

Accrued Expenses - Components of Accrued Expenses (Detail) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Payables and Accruals [Abstract]
Compensation and incentives	$ 2,567,732	$ 1,871,071
Professional services	400,367	329,640
Interest	6,508,621	4,056,337
Accrued insurance obligations	309,826	249,247
Other operating	18,000	45,040
Total accrued expenses	$ 9,804,546	$ 6,551,335

Accrued Expenses - Additional I

Accrued Expenses - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Payables and Accruals [Abstract]
Professional fees	$ 230,500
Accrued incentive awards	800,000	$ 1,800,000
Additional professional fees due in accounts payable	$ 80,509

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail)	Dec. 09, 2002Directors	Jun. 30, 2018USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	May 26, 1998
Related Party Transaction [Line Items]
Post finance cost proceeds	5.00%				5.00%
Deep Sea Mineral Company, CIC, LLC [Member]
Related Party Transaction [Line Items]
Accounts receivable			$ 954,764
Receivable to be paid in cash			202,097
Option to convert receivable to equity			752,667
Back Office Technical and Support Services [Member] | Deep Sea Mineral Company, CIC, LLC [Member]
Related Party Transaction [Line Items]
Accounts receivable			731,746
Monaco [Member]
Related Party Transaction [Line Items]
Accounts receivables			612,498	$ 183,453
Operating payable			233,855	$ 200,801
Lease amount		$ 20,080
Revenue recognized from related party transaction			$ 2,200,000
Georgia LLC [Member]
Related Party Transaction [Line Items]
Post finance cost proceeds	5.00%
Directors' interest in ownership of Company	58.00%
Officers and directors owning an interest in the limited liability | Directors	2

Deferred Income and Revenue P_3

Deferred Income and Revenue Participation Rights - Participating Revenue Rights (Detail) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Deferred Revenue Arrangement [Line Items]
Revenue participation rights	$ 4,643,750	$ 4,643,750
"Cambridge" Project [Member]
Deferred Revenue Arrangement [Line Items]
Revenue participation rights	825,000	825,000
"Seattle" Project [Member]
Deferred Revenue Arrangement [Line Items]
Revenue participation rights	62,500	62,500
Galt Resources, LLC (HMS Victory project) [Member]
Deferred Revenue Arrangement [Line Items]
Revenue participation rights	$ 3,756,250	$ 3,756,250

Deferred Income and Revenue P_4

Deferred Income and Revenue Participation Rights - Additional Information (Detail)	1 Months Ended	12 Months Ended
	Feb. 28, 2011USD ($)	Dec. 31, 2018USD ($)ProjectInvestment$ / Securityshares	Dec. 31, 2016USD ($)
Deferred Revenue Arrangement [Line Items]
Deferred revenue			$ 383,148
Revenue participation agreement		$ 15,000,000
"Seattle" Project [Member]
Deferred Revenue Arrangement [Line Items]
Percentage of revenue owed to certificate holder per each million invested		1.00%
Common shares issued per unit | shares		100,000
Galt Resources, LLC [Member]
Deferred Revenue Arrangement [Line Items]
Percentage of revenue owed to certificate holders		50.00%
Percentage of revenue owed to certificate holder per each million invested		1.00%
Investment multiplier in case of project success | Investment		3
Projects after bifurcation | Project		2
Galt Resources, LLC [Member] | SS Gairsoppa [Member]
Deferred Revenue Arrangement [Line Items]
Deferred revenue		$ 3,756,250
Galt Resources, LLC [Member] | Maximum [Member]
Deferred Revenue Arrangement [Line Items]
Investment for future revenue rights	$ 7,512,500
HMS Victory Project [Member]
Deferred Revenue Arrangement [Line Items]
Percentage of revenue owed to certificate holders		7.5125%
Revenue Participation Certificates [Member] | "Cambridge" Project [Member]
Deferred Revenue Arrangement [Line Items]
Revenue participation certificates per unit value | $ / Security		50,000
Revenue Participation Certificates [Member] | "Seattle" Project [Member]
Deferred Revenue Arrangement [Line Items]
Revenue participation certificates per unit value | $ / Security		50,000
First Payment [Member] | "Cambridge" Project [Member]
Deferred Revenue Arrangement [Line Items]
Percentage of revenue owed to certificate holders		100.00%
Revenue owed to certificate holder		$ 825,000
Second Payment [Member] | "Cambridge" Project [Member]
Deferred Revenue Arrangement [Line Items]
Percentage of revenue owed to certificate holders		24.75%
Second Payment [Member] | "Cambridge" Project [Member] | Minimum [Member]
Deferred Revenue Arrangement [Line Items]
Revenue owed to certificate holder		$ 4,000,000
Second Payment [Member] | "Cambridge" Project [Member] | Maximum [Member]
Deferred Revenue Arrangement [Line Items]
Revenue owed to certificate holder		$ 35,000,000
Third Payment [Member] | "Cambridge" Project [Member]
Deferred Revenue Arrangement [Line Items]
Percentage of revenue owed to certificate holders		12.375%
Revenue owed to certificate holder		$ 35,000,000

Stockholders' Equity_(Deficit_2

Stockholders' Equity/(Deficit) - Additional Information (Detail)	Oct. 31, 2018$ / sharesshares	Mar. 21, 2017shares	Oct. 01, 2016d$ / shares	Mar. 18, 2016d$ / shares	Jun. 09, 2015USD ($)shares	Apr. 30, 2017USD ($)$ / sharesshares	Jun. 30, 2017USD ($)shares	Dec. 31, 2016USD ($)Directors$ / shares	Sep. 30, 2016Directors	Jun. 30, 2016Directors	Dec. 31, 2018USD ($)dIncentive_Plan$ / sharesshares	Dec. 31, 2017USD ($)$ / sharesshares	Dec. 31, 2016USD ($)$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred stock, par value | $ / shares											$ 0.0001	$ 0.0001
Preferred stock, shares authorized											24,984,166	24,984,166
Number of stock incentive plans | Incentive_Plan											2
Stock incentive plan expiration date											Aug. 31, 2015
Compensation costs associated | $											$ 415,615	$ 833,985	$ 1,778,461
Weighted average fair value of options granted | $ / shares											$ 0
Number of outside directors granted quarterly fees | Directors								2	2	2
Weighted average estimated fair value of stock options | $ / shares								$ 1.75			$ 0	$ 0	$ 1.75
Aggregate intrinsic values of options exercisable | $								$ 16,633			$ 15,564	$ 0	$ 16,633
Aggregate intrinsic values of options outstanding | $								16,633			15,564	0	16,633
Aggregate intrinsic values of options exercised | $											0	0	0
Total fair value of shares vested | $											0	231,952	828,497
Total unrecognized compensation related to unvested share-based compensation awards | $											$ 0
2015 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award authorized by board					450,000
Series AA-2 Convertible Preferred Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred stock, par value | $ / shares											$ 0.0001
Preferred stock, shares authorized											7,223,145
Series AA-2 Convertible Preferred Stock [Member] | Penelope Mining LLC [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of trading days | d											20
Series AA-1 Convertible Preferred Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred stock, par value | $ / shares											$ 0.0001
Preferred stock, shares authorized											8,427,004
Preferred stock Liquidation preference accretion rate											8.00%
Epsilon Acquisitions, LLC [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Accrued interest | $												99,998	299,294
Minimum [Member] | Series AA-2 Convertible Preferred Stock [Member] | Penelope Mining LLC [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Closing price of common stock | $ / shares											$ 15.12
Notes Payable, Other Payables [Member] | Epsilon Acquisitions, LLC [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrant right exercise price | $ / shares			$ 3.52
Warrant Expiration Date											Oct. 1, 2021
Warrant right exercise price description											Warrant shall be the number determined by multiplying 120,000 by a fraction, (a) the numerator of which is the aggregate principal amount of advances that have been extended to the OME by Epsilon pursuant to the Restated Note Purchase Agreement on or after the date of the Warrant and prior to the date of such failure and (b) the denominator of which is $3.0 million.
Conversion price of Notes | $ / shares			$ 5	$ 5		$ 3.3
Conversion of stock, shares Issued		670,455				670,455	670,455				670,455
Accrued interest | $						$ 5,000,000	$ 302,274
Number of trading days | d			75	75
Incentive Stock Options [Member] | 2015 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award authorized by board					450,000
Additional shares authorized for stock-based compensation											200,000
Unvested Restricted Stock Awards Excluded from EPS [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of restricted stock, awards vested | $											$ 323,614	408,466	715,406
Fair value of unvested restricted stock awards | $								$ 817,110			$ 460,000	$ 500,754	$ 817,110
Weighted-average grant date fair value of restricted stock awards | $ / shares											$ 0	$ 0	$ 3.54
Weighted-average remaining contractual term											9 months 18 days	1 year	2 years
Total unrecognized compensation cost related to unvested restricted stock awards | $											$ 69,000
Cuota Appreciation Rights [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation costs associated | $											0
Liability associated | $											$ 0
Cuota Appreciation Rights [Member] | Key Employee Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested											249,880
Excersisable											0
Cuota Appreciation Rights [Member] | Non Employee Director Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested											278,000
Vested and Outstanding											500,000
Cuota Appreciation Rights [Member] | Carrying Value [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Value of cuotas of Oceanica | $ / shares											$ 3
Cuota Appreciation Rights [Member] | Fair Value [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Value of cuotas of Oceanica | $ / shares	$ 1.53
Cuota Appreciation Rights [Member] | Maximum [Member] | Key Employee Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award authorized by board											750,000
Cuota Appreciation Rights [Member] | Maximum [Member] | Director Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award authorized by board											600,000
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock and warrants sold	700,000
Repurchases of common stock, shares	700,000
Purchase price of repurchased shares | $ / shares	$ 7.155
Warrant right exercise price | $ / shares	$ 7.155
Warrant Expiration Date	Nov. 2, 2023
Warrant right exercise price description	The warrants have an exercise price of $7.155 per share of common stock and are exercisable in accordance with their terms at any time on or before the close of business on November 2, 2023.
Common Stock [Member] | Incentive Stock Options [Member] | 2015 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of incentive option granted											With respect to each grant of an ISO to a participant who is not a ten percent stockholder, the exercise price shall not be less than the fair market value of a share on the date the ISO is granted. With respect to each grant of an ISO to a participant who is a ten percent stockholder, the exercise price shall not be less than one hundred ten percent (110%) of the fair market value of a share on the date the ISO is granted.
Maximum aggregate number of Shares with respect to one or more Awards that may be granted to any one person during any calendar year					83,333
Maximum aggregate amount of cash that may be paid in cash to any person during any calendar year | $					$ 2,000,000
Common Stock [Member] | Incentive Stock Options [Member] | Minimum [Member] | 2015 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Eligible employee threshold percentage											10.00%
Purchase price of common stock percentage											110.00%

Stockholders' Equity_(Deficit_3

Stockholders' Equity/(Deficit) - Summary of Preferred Stock Allocated to Investors (Detail) - Penelope Mining LLC [Member]	Dec. 31, 2018USD ($)$ / sharesshares
Preferred Stock [Line Items]
Shares | shares	15,650,149
Total Investment | $	$ 144,462,918
Series AA-1 Convertible Preferred Stock [Member]
Preferred Stock [Line Items]
Shares | shares	8,427,004
Price Per Share | $ / shares	$ 12
Total Investment | $	$ 101,124,048
Series AA-2 Convertible Preferred Stock [Member]
Preferred Stock [Line Items]
Shares | shares	7,223,145
Price Per Share | $ / shares	$ 6
Total Investment | $	$ 43,338,870

Stockholders' Equity_(Deficit_4

Stockholders' Equity/(Deficit) - Stock Options Valuation Assumptions (Detail)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life of options	0 years	0 years	8 years 2 months 12 days
Dividend yield			0.00%
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate			1.29%
Expected volatility of common stock			80.87%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate			2.25%
Expected volatility of common stock			82.69%

Stockholders' Equity_(Deficit_5

Stockholders' Equity/(Deficit) - Summary of Stock Option Activity (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Equity [Abstract]
Number of Shares, Outstanding, Beginning	247,817	332,415	375,283
Number of Shares, Granted			22,493
Number of Shares, Exercised	0	0	0
Number of Shares, Cancelled	(9,166)	(84,598)	(65,361)
Number of Shares, Outstanding, Ending	238,651	247,817	332,415
Weighted Average Exercise Price Outstanding, Beginning	$ 16.76	$ 21.55	$ 32.04
Number of Shares, Options exercisable	238,651	247,817	300,751
Weighted Average Exercise Price, Granted			$ 2.74
Weighted Average Exercise Price, Exercised	$ 0	$ 0	0
Weighted Average Exercise Price, Cancelled	36.52	35.59	32.82
Weighted Average Exercise Price, Outstanding, Ending	15.95	16.76	21.55
Weighted Average Exercise Price, Options exercisable	$ 15.95	$ 16.76	$ 22.30

Stockholders' Equity_(Deficit_6

Stockholders' Equity/(Deficit) - Stock Options Outstanding (Detail)	12 Months Ended
	Dec. 31, 2018$ / sharesshares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Shares Outstanding | shares	238,651
Weighted Average Remaining Contractual Life in Years	5 years 10 months 2 days
Weighted Average Exercise Price	$ 15.95
Range One [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices (Minimum)	26.40
Range of Exercise Prices (Maximum)	$ 26.40
Number of Shares Outstanding | shares	75,158
Weighted Average Remaining Contractual Life in Years	5 years
Weighted Average Exercise Price	$ 26.40
Range Two [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices (Minimum)	12.48
Range of Exercise Prices (Maximum)	$ 12.84
Number of Shares Outstanding | shares	141,000
Weighted Average Remaining Contractual Life in Years	6 years
Weighted Average Exercise Price	$ 12.48
Range Three [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices (Minimum)	2.02
Range of Exercise Prices (Maximum)	$ 3.59
Number of Shares Outstanding | shares	22,493
Weighted Average Remaining Contractual Life in Years	7 years 7 months 24 days
Weighted Average Exercise Price	$ 2.74

Stockholders' Equity_(Deficit_7

Stockholders' Equity/(Deficit) - Estimated Fair Value of Restricted Stock Award (Detail) - Unvested Restricted Stock Awards Excluded from EPS [Member] - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares Unvested, Beginning Balance	132,826
Number of Shares, Granted	0
Number of Shares, Vested	(91,159)
Number of Shares, Cancelled	0
Number of Shares Unvested, Ending Balance	41,667	132,826
Weighted Average Grant Date Fair Value Unvested, Beginning Balance	$ 5.90
Weighted Average Grant Date Fair Value, Granted	0	$ 0	$ 3.54
Weighted Average Grant Date Fair Value, Vested	3.55
Weighted Average Grant Date Fair Value, Cancelled	0
Weighted Average Grant Date Fair Value Unvested, Ending Balance	$ 11.04	$ 5.90

Stockholders' Equity_(Deficit_8

Stockholders' Equity/(Deficit) - Summary of Common Stock Warrants Outstanding (Detail)	12 Months Ended
	Dec. 31, 2018$ / sharesshares
Class of Warrant or Right [Line Items]
Common Stock Warrants	885,625
Class of Warrant One [Member]
Class of Warrant or Right [Line Items]
Common Stock Warrants	120,000
Exercise Price | $ / shares	$ 3.52
Termination Date	Jan. 10, 2021
Class of Warrant Two [Member]
Class of Warrant or Right [Line Items]
Common Stock Warrants	65,625
Exercise Price | $ / shares	$ 12
Termination Date	Dec. 7, 2021
Class of Warrant Three [Member]
Class of Warrant or Right [Line Items]
Common Stock Warrants	700,000
Exercise Price | $ / shares	$ 7.16
Termination Date	Feb. 11, 2023

Stockholder's Equity (Deficit)

Stockholder's Equity (Deficit) - Summary of Analysis of Activity in CARs Balances (Detail) - Cuota Appreciation Rights [Member]	12 Months Ended
	Dec. 31, 2018shares
Key Employee Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested at December 31, 2017	229,076
Granted	406,384
Vested	(249,880)
Cancelled	0
Unvested at December 31, 2018	385,580
Non Employee Director Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted	278,000
Vested	(278,000)
Cancelled	0

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2018USD ($)
Income Taxes [Line Items]
Net deferred tax asset	$ 0
Federal [Member]
Income Taxes [Line Items]
Net operating loss carryforwards subject to expiration	$ 167,402,048
Net operating loss carryforwards expiration year	2025
Net operating loss carryforwards expiration year	2037
Net operating loss carryforwards, indefinitely	$ 8,000,000
Foreign [Member]
Income Taxes [Line Items]
Net operating loss carryforwards subject to expiration	39,589,337
2025 Through 2027 [Member]
Income Taxes [Line Items]
Net operating loss carryforwards subject to expiration	43,000,000
2028 Through 2036 [Member]
Income Taxes [Line Items]
Net operating loss carryforwards subject to expiration	$ 116,000,000

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Provision for Income Tax (Benefits) are Attributable to Continuing Operations (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current
Federal	$ 0	$ 0	$ 0
State	0	0	0
Total	0	0	0
Deferred
Federal	0	0	0
State	0	0	0
Total	$ 0	$ 0	$ 0

Income Taxes - Significant Comp

Income Taxes - Significant Components of Deferred Tax Assets and Liabilities (Detail) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Net operating loss and tax credit carryforwards	$ 48,404,432
Capital loss carryforward	147,552
Accrued expenses	559,096
Reserve for Dorado accounts receivable	287,335
Start-up costs	7,042
Excess of book over tax depreciation	707,044
Stock option and restricted stock award expense	1,331,067
Investment in unconsolidated entities	1,387,970
Less: valuation allowance	(52,684,059)	$ (49,235,133)
Deferred tax assets	147,479
Deferred tax liability:
Property and equipment basis	43,155
Prepaid expenses	104,324
Deferred tax liabilities	147,479
Net deferred tax asset	$ 0

Income Taxes - Schedule of Chan

Income Taxes - Schedule of Change in Valuation Allowance (Detail)	12 Months Ended
	Dec. 31, 2018USD ($)
Income Tax Disclosure [Abstract]
Valuation allowance	$ 49,235,133
Change in valuation allowance	3,448,926
Valuation allowance	$ 52,684,059

Income Taxes - Schedule of Inco

Income Taxes - Schedule of Income (Loss) Before Income Taxes (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Expected (benefit)	$ (1,923,757)	$ (3,718,058)	$ (2,186,550)
Effects of:
State income taxes net of federal benefits	(92,707)	(110,667)	(65,082)
Nondeductible expense	29,670	711,679	(1,083,185)
Change in valuation allowance	3,765,560	28,258,724	4,189,828
Foreign Rate Differential	(1,778,766)	(1,097,681)	(855,011)
Change in Deferred Taxes due to enacted changes in tax law		(24,043,997)
Income tax provision (benefit)	$ 0	$ 0	$ 0

Major Customers - Additional In

Major Customers - Additional Information (Detail) - Customer Concentration Risk [Member] - Customer	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Entity Wide Portfolio Carrying Amount, Major Customer [Line Items]
Number of customers	2	1
Sales Revenue, Net [Member] | 2 Customers [Member]
Entity Wide Portfolio Carrying Amount, Major Customer [Line Items]
Customers accounted from total revenue	97.00%
Sales Revenue, Net [Member] | Customer 1 [Member]
Entity Wide Portfolio Carrying Amount, Major Customer [Line Items]
Customers accounted from total revenue		9900.00%

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($) shares in Millions	Mar. 11, 2015	Mar. 31, 2016	Feb. 28, 2011	Dec. 31, 2018	Dec. 31, 2017	Dec. 09, 2002	May 26, 1998
Gain Contingencies [Line Items]
Income derived from Cambridge RPC's				$ 12,986
Post finance cost proceeds						5.00%	5.00%
Consultants contingent success fees				230,500
Cash and cash equivalents				2,786,832	$ 1,108,193
Working capital deficit				37,400,000
Total assets				5,473,170	$ 2,972,426
Penelope Mining LLC [Member]
Gain Contingencies [Line Items]
Investment in convertible preferred stock	$ 101,000,000
Investment agreement period	3 years
MINOSA [Member]
Gain Contingencies [Line Items]
Amount of debt financed	$ 14,750,000
Bank loan amount				$ 14,750,000
Bank loan maturity date				Dec. 31, 2018
Oceanica Resources S. de. R.L [Member]
Gain Contingencies [Line Items]
Grant and potential future issuance of new equity shares		3
Maximum [Member]
Gain Contingencies [Line Items]
Consultants contingent success fees		$ 425,000
Maximum [Member] | Galt Resources [Member]
Gain Contingencies [Line Items]
Investment for future revenue rights			$ 7,512,500
Seattle and Cambridge Projects [Member]
Gain Contingencies [Line Items]
Deferred income from revenue participation rights				$ 887,500

Quarterly Financial Data - Un_3

Quarterly Financial Data - Unaudited - Quarterly Financial Data (Detail) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Selected Quarterly Financial Information [Abstract]
Revenue-net	$ 804,212	$ 886,327	$ 1,073,479	$ 511,735		$ 11,854	$ 587,270	$ 649,353	$ 3,275,753	$ 1,248,477	$ 4,683,035
Gross profit	804,212	886,327	1,073,479	511,735		11,854	587,270	649,353
Net income (loss)	$ (1,476,842)	$ (1,309,275)	$ (641,557)	$ (1,744,762)	$ (1,392,227)	$ (2,251,097)	$ (1,916,885)	$ (2,199,263)	$ (9,104,285)	$ (11,021,142)	$ (9,078,075)
Basic and diluted net income per share	$ (0.16)	$ (0.15)	$ (0.08)	$ (0.21)	$ (0.17)	$ (0.27)	$ (0.23)	$ (0.28)	$ (0.60)	$ (0.95)	$ (0.84)

Other Debt - Additional Informa

Other Debt - Additional Information (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Trade payable, interest bearing interest rate		12.00%
Trade payable in accounts payable		$ 600,000
Collateral asset carrying value		0
Proceeds from sale of marine equipment		$ 1,003,662	$ 80,000	$ 200,000
Magellan Offshore Services Ltd [Member] | Marine Equipment [Member]
Debt Instrument [Line Items]
Proceeds from sale of marine equipment	$ 1,000,000
Gain recognized from sale of marine equipment	900,000
Contingent liability	$ 500,000
Collateral Agreement [Member]
Debt Instrument [Line Items]
Debt instrument maturity date		Aug. 31, 2018

Schedule II - Valuation and Q_2

Schedule II - Valuation and Qualifying Accounts (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Inventory Reserve [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Charged (credited) to expenses	$ 0	$ 0	$ 0
Accounts Receivable Reserve [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year		2,345,729	2,315,797
Charged (credited) to expenses	$ 0	0	0
Charged (credited) to other accounts			29,932
Deductions		$ (2,345,729)
Balance at ending of year			$ 2,345,729