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Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2019	Mar. 11, 2020	Jun. 30, 2019
Cover [Abstract]
Entity Registrant Name	VirnetX Holding Corp
Entity Central Index Key	0001082324
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Public Float			$ 380,524,606
Entity Common Stock, Shares Outstanding		70,787,455
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Address, State or Province	NV

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 3,135	$ 7,611
Investments available for sale	2,394	1,803
Accounts receivables	5	6
Prepaid expenses and other current assets	237	718
Total current assets	5,771	10,138
us-gaap_PrepaidExpenseAndOtherAssetsNoncurrent	1,711	1,604
Property and equipment, net	16	9
Total assets	7,498	11,751
Current liabilities:
Accounts payable and accrued liabilities	1,346	1,050
Accrued payroll and related expenses	287	277
Other current liabilities	193	140
Income tax liability	0	396
Total current liabilities	1,826	1,863
Other liabilities	44	0
Total liabilities	1,870	1,863
Commitments and contingencies (Note 4)
Stockholders' equity:
Preferred stock, par value $0.0001 per share Authorized: 10,000,000 shares at December 31, 2019 and December 31, 2018, Issued and outstanding: 0 shares at December 31, 2019 and December 31, 2018	0	0
Common stock, par value $0.0001 per share Authorized: 100,000,000 shares at December 31, 2019 and December 31, 2018, Issued and outstanding: 69,586,764 shares and 66,879,847 shares, at December 31, 2019 and December 31, 2018, respectively	7	7
Additional paid-in capital	223,237	208,317
Accumulated deficit	(217,602)	(198,422)
Accumulated other comprehensive loss	(14)	(14)
Total stockholders' equity	5,628	9,888
Total liabilities and stockholders' equity	$ 7,498	$ 11,751

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Stockholders' equity:
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	69,586,764	66,879,847
Common stock, shares outstanding (in shares)	69,586,764	66,879,847

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
CONSOLIDATED STATEMENTS OF OPERATIONS [Abstract]
Revenue	$ 85	$ 63
Operating expense:
Research and development	3,845	4,815
Selling, general and administrative expenses	15,905	20,705
Total operating expense	19,750	25,520
Loss from operations	(19,665)	(25,457)
Interest and other income, net	92	54
Loss before taxes	(19,573)	(25,403)
Income tax benefit (expense)	393	(3)
Net loss	$ (19,180)	$ (25,406)
Basic and diluted loss per share (in dollars per share)	$ (0.28)	$ (0.40)
Weighted average shares outstanding basic and diluted (in shares)	68,564,321	62,985,763

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS [Abstract]
Net loss	$ (19,180)	$ (25,406)
Other comprehensive (loss), net of tax:
Change in unrealized gain (loss) on investments	3	(1)
Change in foreign currency translation	(3)	0
Total other comprehensive income gain (loss), net of tax	0	(1)
Comprehensive loss	$ (19,180)	$ (25,407)

- Definition

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

+ References + Details

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]	Total
Balance at Dec. 31, 2017	$ 6	$ 177,076	$ (175,516)	$ (13)	$ 1,553
Balance (Cumulative Effect of Accounting Change [Member]) at Dec. 31, 2017			2,500		2,500
Balance (in shares) at Dec. 31, 2017	59,051,978
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued for cash, net		27,051			27,052
Stock issued for cash, net (in shares)	7,510,555
Stock issued for options and RSUs, net		135			135
Stock issued for options and RSUs, net (in shares)	317,314
Stock-based compensation		4,055			4,055
Comprehensive income:
Net loss			(25,406)		(25,406)
Change in foreign currency translation, net of tax					0
Change in unrealized losses, net of tax				(1)	(1)
Comprehensive loss					(25,407)
Balance at Dec. 31, 2018	$ 7	208,317	(198,422)	(14)	9,888
Balance (in shares) at Dec. 31, 2018	66,879,847
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued for cash, net		10,539			10,539
Stock issued for cash, net (in shares)	1,860,483
Stock issued for options and RSUs, net		670			670
Stock issued for options and RSUs, net (in shares)	846,434
Stock-based compensation		3,711			3,711
Comprehensive income:
Net loss			(19,180)		(19,180)
Change in foreign currency translation, net of tax				(3)	(3)
Change in unrealized losses, net of tax				3	3
Comprehensive loss					(19,180)
Balance at Dec. 31, 2019	$ 7	$ 223,237	$ (217,602)	$ (14)	$ 5,628
Balance (in shares) at Dec. 31, 2019	69,586,764

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Minimum [Member]
Stock issued for cash, net (in dollars per share)	$ 4.00	$ 3.00
Maximum [Member]
Stock issued for cash, net (in dollars per share)	$ 6.49	$ 4.89

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net loss	$ (19,180)	$ (25,406)
Adjustments to reconcile net loss to net cash from operating activities:
Depreciation	7	18
Stock-based compensation	3,711	4,055
Changes in assets and liabilities:
Prepaid expenses and other current assets	374	258
Accounts payable	296	636
Other liabilities	97	0
Accrued payroll and related expenses	10	(1,856)
Accounts receivable	1	(6)
Income tax liability	(396)	3
Net cash used in operating activities	(15,080)	(22,298)
Cash flows from investing activities:
Purchase of property and equipment	(14)	0
Purchase of investments	(5,784)	(3,090)
Proceeds from sale or maturity of investments	5,192	2,720
Net cash used in investing activities	(606)	(370)
Cash flows from financing activities:
Proceeds from exercise of options	816	135
Proceeds from sale of common stock	10,539	27,052
Payments on payroll taxes on cashless exercise of RSUs	(145)	(43)
Net cash provided by financing activities	11,210	27,144
Net increase (decrease) in cash and cash equivalents	(4,476)	4,476
Cash and cash equivalents, beginning of period	7,611	3,135
Cash and cash equivalents, end of period	3,135	7,611
Cash paid for income taxes	4	3
ASC 606 [Member]
Cash flows from financing activities:
Deferred revenue reclassified to retained earnings - ASC 606 adoption	$ 0	$ 2,500

Formation and Business of the Company	12 Months Ended
Formation and Business of the Company	Dec. 31, 2019
Formation and Business of the Company [Abstract]
Formation and Business of the Company	Note 1 − Formation and Business of the Company VirnetX Holding Corporation, which we refer to as” we”, “us”, “our”, “the Company” or “VirnetX”, is engaged in the business of commercializing a portfolio of patents. We seek to license our technology, including GABRIEL Connection Technology™, to various original equipment manufacturers, or OEMs, that use our technologies in the development and manufacturing of their own products within the IP-telephony, mobility, fixed-mobile convergence and unified communications markets. Prior to 2012 our revenue was limited to an insignificant amount of software royalties pursuant to the terms of a single license agreement. During 2013 and 2012 we had revenues from settlements of patent infringement disputes whereby we received consideration for past sales of licensees that utilized our technology, where there was no prior patent license agreement (see “Revenue Recognition”). Our portfolio of intellectual property is the foundation of our business model. We currently own approximately 194 total patents and pending applications, including 70 U.S. patents/patent applications and 124 foreign patents/validations/pending applications. Our patent portfolio is primarily focused on securing real-time communications over the Internet, as well as related services such as the establishment and maintenance of a secure domain name registry. Our patented methods also have additional applications in the key areas of device operating systems and network security for Cloud services, M2M communications in areas of Smart City, Connected Car and Connected Home. The subject matter of all our U.S and foreign patents and pending applications relates generally to securing communications over the internet and such covers all our technology and other products. Our issued U.S. and foreign patents expire at various times during the period from 2019 to 2024. Some of our issued patents and pending patent applications were acquired by our principal operating subsidiary; VirnetX, Inc., from Leidos, (f/k/a Science Applications International Corporation or SAIC) in 2006 and we are required to make payments to Leidos, based on cash or certain other values generated from those patents. The amount of such payments depends upon the type of value generated, and certain categories are subject to maximums and other limitations.

Summary of Significant Accounting Policies	12 Months Ended
Summary of Significant Accounting Policies	Dec. 31, 2019
Summary of Significant Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Note 2 − Summary of Significant Accounting Policies The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reported period. The critical accounting policies we employ in the preparation of our consolidated financial statements are those which involve impairment of long-lived assets, income taxes, fair value of financial instruments and stock-based compensation. Use of Estimates We prepare our consolidated financial statements in accordance with accounting principles generally accepted in the U.S. (“U.S. GAAP”). In doing so, we have to make estimates and assumptions that affect our reported amounts of assets, liabilities, revenues, and expenses, as well as related disclosure of contingent assets and liabilities. In some cases, we could reasonably have used different accounting policies and estimates. In some cases, changes in the accounting estimates are reasonably likely to occur from period to period. Accordingly, actual results could differ materially from our estimates. To the extent that there are material differences between these estimates and actual results, our financial condition or results of operations will be affected. We base our estimates on past experience and other assumptions that we believe are reasonable under the circumstances, and we evaluate these estimates on an ongoing basis. We refer to accounting estimates of this type as critical accounting policies and estimates, which we discuss further below. We have reviewed our critical accounting policies and estimates with the audit committee of our board of directors. Basis of Consolidation The consolidated financial statements include the accounts of VirnetX Holding Corporation and our wholly owned subsidiaries. All intercompany balances and transactions have been eliminated. Leases The Company determines if an arrangement is a lease at inception in accordance with Accounting Standards Codification (“ASC”) Topic 842. Operating lease right-of-use (“ROU”) assets are included in Prepaid expense, and other assets on the Consolidated Balance Sheet. ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. ROU assets and lease liabilities are recognized at the commencement date based on the present value of lease payments over the lease term. (See Note 14) Revenue Recognition We derive our revenue from patent licensing. The timing and amount of revenue recognized from each licensee depends upon a variety of factors, including the specific terms of each agreement and the nature of the deliverables and obligations. Such agreements may be complex and include multiple elements. These agreements may include, without limitation, elements related to the settlement of past patent infringement liabilities, up-front and non-refundable license fees for the use of patents, patent licensing royalties on covered products sold by licensees, and the compensation structure and ownership of intellectual property rights associated with contractual technology development arrangements. We account for revenue in accordance with Accounting Standards Update (“ASU”) No.2014-09, Revenue from Contracts with Customers (“Topic 606”), which we adopted on January 1, 2018 using the modified-retrospective method. Under Topic 606 a performance obligation is a promise in a contract to transfer a distinct good or service to the customer. A contract’s transaction price is allocated to each distinct performance obligation and recognized as revenue when, or as, the performance obligation is satisfied. Our revenue arrangements may consist of multiple-element arrangements, with revenue for each unit of accounting recognized as the product or service is delivered to the customer. With the licensing of our patents, performance obligations are generally satisfied at a point in time as work is complete and our patent rights are transferred to our customers. We generally have no further obligation to our customers regarding our technology. Certain contracts may require our customers to enter into a hosting arrangement with us and for these arrangements’ revenue is recognized over time, generally over the life of the servicing contract. Contingent Gains We recognize gain contingencies in accordance with ASC 450-30-25 which prohibits recognition of contingent gains until realized. Accordingly, we do not record contingent gains ahead of such realization. Management generally considers any such gains as realized only upon the collection of cash. Cash and Cash Equivalents We consider all highly liquid investments purchased with original maturities of three months or less at the date of purchase to be cash equivalents. Our cash and cash equivalents are not subject to significant interest rate risk due to the short maturities of these investments. Prepaid Expenses and Other Current Assets Prepaid Expense and Other Current Assets on the consolidated balance sheet at December 31, 2018 includes the current portion of prepaid rent for a facility lease for corporate promotional and marketing purposes, and this balance is included in ROU assets as of December 31, 2019 (see Note 14 - Effects of Adopting ASU Topic 842 – Leases, below). In a prior year, the Company prepaid $4,000 which is being amortized over the remaining balance of the lease. The unamortized non-current portion of the prepayment is included in Prepaid Expenses-Non-current on the consolidated balance sheet. Investments Investments are classified as available-for-sale and are recorded at fair market value. Unrealized gains and losses are reported as other comprehensive income. Realized gains and losses are recorded in income in the period they are realized using specific identification of each security’s cost basis. We invest our excess cash primarily in highly liquid debt instruments including corporate, government and federal agency securities, with contractual maturities less than two years. By policy, we limit the amount of credit exposure to any one issuer. Property and Equipment Property and equipment are stated at historical cost, less accumulated depreciation and amortization. Depreciation and amortization are computed using the accelerated and straight-line methods over the estimated useful lives of the assets, which range from five to seven years. Repair and maintenance costs are charged to expense as incurred. Concentration of Credit Risk and Other Risks and Uncertainties Our cash and cash equivalents are primarily maintained at two major financial institutions in the United States. Deposits held with these financial institutions may exceed the amount of insurance provided on such deposits. A portion of those balances are insured by the Federal Deposit Insurance Corporation, or FDIC. During the year ended December 31, 2019 and 2018, we had, at times, funds that were uninsured. We do not believe that we are subject to any unusual financial risk beyond the normal risk associated with commercial banking relationships. We have not experienced any losses on our deposits of cash and cash equivalents. Fair Value The carrying amounts of our financial instruments, including cash equivalents, accounts payable, and accrued liabilities, approximate fair value because of their generally short maturities. Intangible Assets We record intangible assets at cost, less accumulated amortization. Amortization of intangible assets is provided over their estimated useful lives, which can range from 3 to 15 years, on either a straight-line basis or as revenue is generated by the assets. Impairment of Long-Lived Assets We identify and record impairment losses on long-lived assets used in operations when events and changes in circumstances indicate that the carrying amount of an asset might not be recoverable, but not less than annually. Recoverability is measured by comparison of the anticipated future net undiscounted cash flows to the related assets’ carrying value. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the projected discounted future net cash flows arising from the asset. Research and Development Research and development costs include expenses paid to outside development consultants and compensation related expenses for our engineering staff. Research and development costs are expensed as incurred. Income Taxes We account for income taxes using the asset and liability method. The asset and liability method requires the recognition of deferred tax assets and liabilities for expected future tax consequences of temporary differences that currently exist between the tax basis and financial reporting basis of our assets and liabilities. We calculate current and deferred tax provisions based on estimates and assumptions that could differ from actual results reflected on the income tax returns filed during the following years. Adjustments based on filed returns are recorded when identified in the subsequent years. The effect on deferred taxes for a change in tax rates is recognized in income in the period that the tax rate change is enacted. In assessing our deferred tax assets, we consider whether it is more likely than not that all or some portion of the deferred tax assets will not be realized. A valuation allowance is provided for deferred income tax assets when, in our judgment, based upon currently available information and other factors, it is more likely than not that all or a portion of such deferred income tax assets will not be realized. The determination of the need for a valuation allowance is based on an on-going evaluation of current information including, among other things, historical operating results, estimates of future earnings in different taxing jurisdictions and the expected timing of the reversals of temporary differences. We believe the determination to record a valuation allowance to reduce a deferred income tax asset is a significant accounting estimate because it is based, among other things, on an estimate of future taxable income in the United States and certain other jurisdictions, which is susceptible to change and may or may not occur, and because the impact of adjusting a valuation allowance may be material. In determining when to release the valuation allowance established against our net deferred income tax assets, we consider all available evidence, both positive and negative. Consistent with our policy, and because of our history of operating losses, we do not currently recognize the benefit of all of our deferred tax assets, including tax loss carry forwards, that may be used to offset future taxable income. We continually assess our ability to generate sufficient taxable income during future periods in which our deferred tax assets may be realized. If and when we believe it is more likely than not that we will recover our deferred tax assets, we will reverse the valuation allowance as an income tax benefit in our statements of operations. We account for our uncertain tax positions in accordance with U.S. GAAP. The U.S. GAAP method of accounting for uncertain tax positions utilizes a two-step approach to evaluate tax positions. Step one, recognition, requires evaluation of the tax position to determine if based solely on technical merits it is more likely than not to be sustained upon examination. Step two, measurement, is addressed only if a position is more likely than not to be sustained. In step two, the tax benefit is measured as the largest amount of benefit, determined on a cumulative probability basis, which is more likely than not to be realized upon ultimate settlement with tax authorities. If a position does not meet the more likely than not threshold for recognition in step one, no benefit is recorded until the first subsequent period in which the more likely than not standard is met, the issue is resolved with the taxing authority, or the statute of limitations expires. Positions previously recognized are derecognized when we subsequently determine the position no longer is more likely than not to be sustained. Evaluation of tax positions, their technical merits, and measurements using cumulative probability are highly subjective management estimates. Actual results could differ materially from these estimates. Stock-Based Compensation We account for stock-based compensation using the fair value recognition method in accordance with U.S. GAAP. We recognize these compensation costs on a straight-line basis over the requisite service period of the award, which is generally the vesting term of 4 years. We do not estimate the forfeiture rate and recognize forfeitures, if any, when they occur. See Note 6 - Stock-Based Compensation below for additional information concerning our share-based compensation awards. In addition, as required we record stock-based compensation expense for awards granted to non-employees at fair value of the consideration received or the fair value of the equity instruments issued as they vest over the performance period. Earnings per Share Basic earnings per share are computed by dividing earnings available to common stockholders by the weighted average number of outstanding common shares during the period. Diluted earnings per share is computed by dividing net income by the weighted average number of shares outstanding during the period increased to include the number of additional shares of common stock that would have been outstanding if the potentially dilutive securities had been issued. During 2019, and 2018 we incurred losses; therefore, the effect of any common stock equivalent would be anti-dilutive during these periods. New Accounting Pronouncements In December 2019 the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2019-12 Income Taxes (Topic 740). The amendments in this ASU simplify the accounting for income taxes by removing certain exceptions to the general principles in Topic 740. The amendments also improve consistent application of and simplify GAAP for other areas of Topic 740 by clarifying and amending existing guidance. The amendments in this ASU are effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. We are currently evaluating the impact, if any this ASU will have on our consolidated financial statements and related disclosures. In August 2018 the FASB issued ASU 2018-13 - Fair Value Measurement (Topic 820). The FASB is issuing the amendments in this ASU as part of the disclosure framework project. On March 4, 2014, the Board issued a proposed FASB Concepts Statement, Conceptual Framework for Financial Reporting—Chapter 8: Notes to Financial Statements, which the Board finalized on August 28, 2018. The disclosure framework project’s objective and primary focus are to improve the effectiveness of disclosures in the notes to financial statements by facilitating clear communication of the information required by GAAP that is most important to users of each entity’s financial statements. The amendments in this ASU are effective for all entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. We will adopt this guidance on January 1, 2020 and expect this guidance will have no material impact on our financial position and statement of operations. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses (“Topic 326”). The purpose of this ASU is to require a financial asset measured at amortized cost basis to be presented at the net amount expected to be collected. Credit losses relating to available-for-sale debt securities should be recorded through an allowance for credit losses. This ASU is effective for interim and annual reporting periods beginning after December 15, 2019. We will adopt this guidance on January 1, 2020 and expect this guidance will have no material impact on our financial position and statement of operations. In February 2016, FASB issued ASU No. 2016-02, Leases (Topic 842) as amended and supplemented by subsequent ASU’s, (“ASU 2016-02”). ASU 2016-02 requires an entity to recognize ROU assets and lease liabilities on its balance sheet and disclose key information about leasing arrangements. For public companies, ASU 2016-02 is effective for annual reporting periods beginning after December 15, 2018, including interim periods within that reporting period, and requires a modified retrospective adoption, with early adoption permitted. We adopted this ASU on January 1, 2019 which had no impact on our consolidated statements of operations. In May 2014, the FASB issued ASU No. 2014-09 Revenue from Contracts with Customers (“Topic 606”). As amended, Topic 606 supersedes prior revenue recognition requirements including most industry-specific revenue recognition guidance. On January 1, 2018 we adopted this standard using the modified retrospective method which resulted in a $2,500 decrease in accumulated deficit and a $2,500 decrease in deferred revenue in our consolidated balance sheet.

Property and Equipment

12 Months Ended

Dec. 31, 2019

Property and Equipment [Abstract]

Property and Equipment

Note 3 − Property and Equipment

Our major classes of property and equipment were as follows:

	December 31
	2019			2018
Office furniture	$	79		$	79
Computer equipment		81			67
Total		160			146
Less accumulated depreciation		(144	)		(137	)
Total property and equipment, net	$	16		$	9

Depreciation expense for the years ended December 31, 2019 and 2018 was $7, and $18, respectively.

Commitments, Contingencies and Related Party Transactions	12 Months Ended
	Dec. 31, 2019
Commitments and Related Party Transactions [Abstract]
Commitments and Related Party Transactions	Note 4 − Commitments, Contingencies and Related Party Transactions We lease our offices under an operating lease with a third party expiring in October 2021. We recognize rent expense on a straight-line basis over the term of the lease. Rent expense was $56, for each of the years ended December 31, 2019, and 2018. Future minimum rents due under the lease total $102 in 2019, of which $56 is due in 2020 and $46 is due in 2021, when the lease expires. We entered into a service agreement for the use of an aircraft from K2 Investment Fund LLC (“LLC”) for business travel for employees of the Company. We incurred approximately $1,790 and $1,590 in rental fees and reimbursements to the LLC during the years ended December 31, 2019 and 2018, respectively. We pay for the Company’s usage of the aircraft and have no rights to purchase. Our Chief Executive Officer and Chief Administrative Officer are the managing partners of the LLC and control the equity interests of the LLC. We entered into a 12-month non-exclusive agreement with the LLC for use of the plane at a rate of $8 per flight hour, with no minimum usage requirement. The agreement contains other terms and conditions normal in such transactions and can be cancelled by either us or the LLC with 30 days’ notice. The agreement renews on an annual basis unless terminated by either party. Neither party has exercised their termination rights.

Stock Plan	12 Months Ended
Stock Plan	Dec. 31, 2019
Stock Plan [Abstract]
Stock Plan	Note 5 − Stock Plan We have a stock incentive plan for employees and others called the VirnetX Holding Corporation 2013 Equity Incentive Plan (the “2013 Plan”), which has been approved by our stockholders. To the extent that any award should expire, become un-exercisable or is otherwise forfeited, the shares subject to such award will again become available for issuance under the 2013 Plan. The 2013 Plan provides for the granting of stock options and restricted stock units purchase rights (“RSUs”) to our employees and consultants. Stock options granted under the 2013 Plan may be incentive stock options or nonqualified stock options. Incentive stock options (“ISOs”) may only be granted to our employees (including officers and directors). Nonqualified stock options (“NSOs”) and stock purchase rights may be granted to our employees and consultants. The 2013 Plan will expire in 2023. Options may be granted under the 2013 Plan with an exercise price determined by our Board of Directors, or a duly appointed committee thereof, provided, however, that the exercise price of an option granted to any employee shall be not less than 100% of the fair market value at the date of grant in the case of ISOs or 85% of the fair market value at the date of grant in the case of an NSO. The exercise price of an ISO or NSO granted to one of our Named Executive Officers shall not be less than 100% fair market value of the shares at the date of grant and the exercise price of an ISO granted to a 10% shareholder shall not be less than 110% of the fair market value of the shares on the date of grant. Stock options granted under the 2013 Plan typically vest over four years and have a 10-year term. All RSUs are considered to be granted at the fair value of our stock on the date of grant because they have no exercise price. RSUs typically vest over four years. At December 31, 2019, there were 1,208,070 shares available for grant under the 2013 Plan.

Stock-Based Compensation

12 Months Ended

Dec. 31, 2019

Stock-Based Compensation [Abstract]

Stock-Based Compensation

Note 6 − Stock-Based Compensation

The following tables summarize information about stock options and RSUs outstanding at December 31, 2019:

Options Outstanding								Options Vested and Exercisable
Range of Exercise Prices	Number Outstanding		Weighted Average Remaining Contractual Life (Years)		Weighted Average Exercise Price			Number Exercisable		Weighted Average Remaining Contractual Life (Years)		Weighted Average Exercise Price
$ 2.35 - 6.95		4,376,396		7.08		$	4.29		2,826,062		6.48		$	4.31
$ 14.52 - 35.25		1,253,625		2.71		$	23.16		1,253,625		2.71		$	23.16
		5,630,021		6.11		$	8.49		4,079,687		5.32		$	10.10

The following tables summarize activity under the Plan for the indicated periods:

	Options
	Number of Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value
Outstanding at December 31, 2017		5,138,066		$	8.41		—	$	—
Options granted		1,095,000			3.52		—		—
Options exercised		(117,229	)		1.15		—		—
Options cancelled		(117,000	)		5.34		—		—
Outstanding at December 31, 2018		5,998,837		$	7.72		—	$	—
Options granted		345,000			6.06		—		—
Options exercised		(663,816	)		1.23		—		—
Options cancelled		(50,000	)		4.95		—		—
Outstanding at December 31, 2019		5,630,021		$	8.49		6.11	$	516
Options exercisable at December 31, 2019		4,079,687		$	10.10		5.32	$	314

	RSUs
	Number of RSUs			Weighted Average Grant Date Fair Value		Aggregate Intrinsic Value
Outstanding at December 31, 2017		469,661		$	5.19	$	—
RSUs granted		246,663			3.26		—
RSUs vested		(211,330	)		6.19		—
Outstanding at December 31, 2018		504,994		$	3.83	$	—
RSUs granted		229,996			6.06		—
RSUs vested		(207,334	)		4.07		—
RSUs cancelled		(29,167	)		4.65
Outstanding at December 31, 2019		498,489		$	4.71	$	86

Intrinsic value is calculated as the difference between the per-share market price of our common stock on the last trading day of 2019, which was $3.80 and the exercise price of the options. For options exercised, the intrinsic value is the difference between market price and the exercise price on the date of exercise. We received cash proceeds of $816 and $135 from stock options exercised in 2019 and 2018, respectively. The total intrinsic value of options exercised was $2,473 and $46 during the years ended December 31, 2019 and 2018, respectively.

Stock-based compensation expense is included in general and administrative expense for each period as follows:

Stock-Based Compensation by Type of Award	Year Ended December 31, 2019		Year Ended December 31, 2018
Stock options	$	2,756	$	2,926
RSUs		955		1,129
Total stock-based compensation expense	$	3,711	$	4,055

As of December 31, 2019, there was $4,801 of unrecognized stock-based compensation expense related to unvested employee stock options and $1,882 of unrecognized stock-based compensation expense related to unvested RSUs. These costs are expected to be recognized over a weighted-average period of 2.13 and 2.33 years, respectively.

The fair value of each option grant was estimated on the date of grant using the Black-Scholes option pricing model using the following weighted average assumptions:

	Year Ended December 31, 2019			Year Ended December 31, 2018
Expected stock price volatility		92.34	%		85.26	%
Risk-free interest rate		2.09	%		2.73	%
Expected life term	6.14 years			6.02 years
Expected dividends		0	%		0	%

Based on the Black-Scholes option pricing model, the weighted average estimated fair value of employee stock options granted was $4.63 and $2.58 per share during the years ended December 31, 2019 and 2018, respectively.

The expected life was determined using the simplified method outlined in ASC 718, “Compensation - Stock Compensation”. Expected volatility of the stock options was based upon historical data and other relevant factors. We have not provided an estimate for forfeitures because we have had nominal forfeited options and RSUs and believed that all outstanding options and RSUs at December 31, 2019, would vest.

Earnings Per Share

12 Months Ended

Dec. 31, 2019

Earnings Per Share [Abstract]

Earnings Per Share

Note 7 − Earnings Per Share

Basic earnings per share are based on the weighted average number of shares outstanding for a period. Diluted earnings per share are based upon the weighted average number of shares and potentially dilutive common shares outstanding. Potential common shares outstanding principally include stock options, under our stock plan and warrants. During 2019, and 2018 we incurred losses; therefore, the effect of any common stock equivalent would be anti-dilutive during those periods.

The table below sets forth the basic and diluted loss per share calculations:

	2019			2018
Net loss	$	(19,180	)		(25,406	)
Basic and diluted weighted average number of shares outstanding		68,564			62,986
Basic and diluted loss per share	$	(0.28	)		(0.40	)

Common Stock	12 Months Ended
Common Stock	Dec. 31, 2019
Common Stock [Abstract]
Common Stock	Note 8 − Common Stock Each share of common stock has the right to one vote. The holders of common stock are entitled to receive dividends whenever funds are legally available and when declared by our Board of Directors, subject to the prior rights of holders of all classes of stock outstanding having priority rights as to dividends. Our restated articles of incorporation authorize us to issue up to 100,000,000 shares of $.0001 par value common stock. In August 2015, we filed a universal shelf registration statement with the SEC enabling us to offer and sell from time to time up to $100 million of equity, debt or other types of securities. We also entered into an at-the-market (“ATM”) equity offering sales agreement with Cowen & Company, LLC in August 2015, under which we may offer and sell shares of our common stock having an aggregate value of up to $35 million. On March 8, 2018, we amended our August 20, 2015 equity offering sales agreement with Cowen whereby the maximum aggregate value of the Company’s common stock we could offer and sell, from time to time, was increased from $35,000 to $50,000. This registration statement expired on September 2, 2018. On July 30, 2018 we filed a $100,000 replacement universal shelf registration statement on SEC Form S-3. This replacement registration statement was declared effective by the SEC on August 16, 2018. We also entered a new ATM with Cowen on August 31, 2018, under which we could offer and sell shares of our common stock having an aggregate value of up to $50,000. We use the ATM proceeds for GABRIEL product development and marketing, and general corporate purposes, which may include working capital, capital expenditures, other corporate expenses and acquisitions of complementary products, technologies or businesses. As of December 31, 2019, common stock with an aggregate value of up to $26,592 remained available for offer and sale under the ATM agreement. We sold 1,860,483 and 7,510,555 shares of common stock under the ATM program during the years ended December 31, 2019 and 2018 respectively. The average sales price per common share sold during the year ended December 31, 2019 was $5.84 and the aggregate proceeds from the sales totaled $10,866 during the period. Sales commissions, fees and other costs associated with the ATM transactions totaled $326 for 2019. The average sales price per common share sold during the year ended December 31, 2018 was $3.71 and the aggregate proceeds from the sales totaled $27,837 during the period. Sales commissions, fees and other costs associated with the ATM transactions totaled $785 for 2018 (see Note 15 Subsequent Events). In addition, in 2015 we issued warrants for the purchase of 25,000 shares of common stock which are exercisable at a price of $7 per share and expire in April 2020.

Employee Benefit Plan	12 Months Ended
Employee Benefit Plan	Dec. 31, 2019
Employee Benefit Plan [Abstract]
Employee Benefit Plan	Note 9 − Employee Benefit Plan We sponsor a defined contribution 401k plan covering substantially all our employees. Our matching contribution to the plan was approximately $101 and $95 in 2019 and 2018, respectively.

Income Taxes

12 Months Ended

Dec. 31, 2019

Income Taxes [Abstract]

Income Taxes

Note 10 − Income Taxes

The income tax benefit (provision) is comprised of the following:

	Year Ended December 31, 2019		Year Ended December 31, 2018
Current:
Federal	$	—	$	—
State		393		(3	)
Foreign		—		—
		393		(3	)
Deferred:
Federal		—		—
State		—		—
Total income tax provision	$	393	$	(3	)

A reconciliation of the United States federal statutory income tax rate to our effective income tax rate is as follows:

	Year Ended December 31, 2019			Year Ended December 31, 2018
United States federal statutory rate		21.00	%		21.00	%
State taxes, net of federal benefit		1.99	%		(0.01	)%
Valuation allowance		(21.96	)%		(24.33	)%
Accounting method change - ASC 606		—			2.07	%
R&D Credit		1.34	%		1.53	%
Other		(0.38	)%		(0.27	)%
Effective income tax rate		1.99	%		(0.01	)%

In 2019 and 2018, we had pre-tax losses of $19,573 and $25,403 respectively, which are available for carry forward to offset future taxable income. We made determinations to provide full valuation allowances for our net deferred tax assets at the end of 2019 and 2018, including NOL carryforwards generated during the years, based on our evaluation of positive and negative evidence, including our history of operating losses and the uncertainty of generating future taxable income that would enable us to realize our deferred tax assets.

Deferred tax assets (liabilities) consist of the following:

	As of December 31, 2019			As of December 31, 2018
Deferred tax assets:
Reserves and accruals	$	62		$	45
Research and development credits and other credits		1,730			1,635
Net operating loss carry forward		27,907			25,733
Stock based compensation		8,402			8,857
Other		11			26
Total deferred tax assets		38,112			36,296

Valuation allowance		(38,112	)		(36,296	)
Deferred tax assets after valuation allowance		—			—

Total deferred tax liability		—			—

Net deferred tax assets (liabilities)	$	—		$	—

In assessing the realization of deferred tax assets, management considers whether it is more likely than not that a portion of the net deferred assets will not be realized. The ultimate realization of the net deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. Based on the available objective evidence, management believes it is more likely than not that the net deferred tax assets at December 31, 2019 will not be realizable. Accordingly, management has maintained a full valuation allowance against its net deferred tax assets at December 31, 2019. The net change in the total valuation allowance for the 12 months ended December 31, 2019 was an increase of $1,816.

At December 31, 2019, we had federal and state net operating loss carryforwards of approximately $131,055 and $107,989, respectively, expiring beginning in 2028 for federal and in 2029 for state, respectively. At December 31, 2019, we had federal research and development creditcarryforwards of approximately $1,730, expiring beginning in 2032.

Internal Revenue Code Section 382 places a limitation (the “Section 382 Limitation”) on the amount of net operating loss carry forwards that can be used to offset taxable income after a change in control (generally greater than 50% change in ownership) of a loss corporation. California, the state in which our headquarters was once located, has similar rules. Our capitalization may have resulted in such a change. Generally, after a control change, a loss corporation cannot deduct net operating loss carry forwards generated in years prior to the deemed change of control under IRC Section 382 in excess of the Section 382 Limitation.

We are required to recognize the financial statement effects of a tax position when it is more likely than not, based on the technical merits, that the position will be sustained upon examination. As a result, we have provided an allowance for an uncertain tax position under ASC 740-10 of $0 and $316 at December 31, 2019 and December 31, 2018, respectively. In 2019, we released all ASC 740-10 uncertain tax positions due to the expiring of the statute of limitation.

Our tax returns are subject to review by various tax authorities. The returns subject to review are those from 2005 forward.

Our policy is to recognize interest and penalties, if any, accrued on any unrecognized tax benefits, as a component of income tax expense. We had no interest or penalties accrued for the year ended December 31, 2019.

Reconciliation of provision for uncertain tax position discussed above:

	Year Ended December 31, 2019			Year Ended December 31, 2018
Balance at the beginning of the year	$	316		$	316
Additions based on tax positions related to the current year		—			—
Additions for tax positions of prior years		—			—
Settlements		—			—
Lapse of applicable statute of limitations		(316	)		—
Balance at the end of the year	$	—		$	316

Fair Value Measurement

12 Months Ended

Dec. 31, 2019

Fair Value Measurement [Abstract]

Fair Value Measurement

Note 11 − Fair Value Measurement

We apply fair value accounting for all financial assets and liabilities and non-financial assets and liabilities that are recognized or disclosed at fair value in the financial statements on a recurring basis. Fair value is estimated by applying the following hierarchy, which prioritizes the inputs used to measure fair value into three levels and bases the categorization within the hierarchy upon the lowest level of input that is available and significant to the fair value measurement:

Level 1 – Quoted prices in active markets for identical assets or liabilities.

Level 2 – Observable inputs other than quoted prices in active markets for identical assets and liabilities, quoted prices for identical or similar assets or liabilities in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

Level 3 – Inputs that are generally unobservable and typically reflect management’s estimate of assumptions that market participants would use in pricing the asset or liability.

The carrying amounts for cash and cash equivalents, investments in certificates of deposit, accounts payable and accrued expenses approximate their fair values due to the short period of time until maturity.

Mutual funds: Valued at the quoted net asset value (NAV) of shares held.

U.S. agency securities: Fair value measured at the closing price reported on the active market on which the individual securities are traded.

The following table shows the adjusted cost, gross unrealized gains, gross unrealized losses and fair value of our financial assets as of December 31, 2019 and 2018 (in thousands):

	December 31, 2019
	Adjusted Cost		Unrealized Gains		Unrealized Losses		Fair Value		Cash and Cash Equivalents		Investments Available for Sale
Cash	$	2,076	$	—	$	—	$	2,076	$	2,076	$	—
Level 1:
Mutual funds		613		—		—		613		613		—
U.S. agency securities		2,837		3		—		2,840		446		2,394
		3,450		3		—		3,453		1,059		2,394
Total	$	5,526	$	3	$	—	$	5,529	$	3,135	$	2,394

	December 31, 2018
	Adjusted Cost		Unrealized Gains		Unrealized Losses		Fair Value		Cash and Cash Equivalents		Investments Available for Sale
Cash	$	5,048	$	—	$	—	$	5,048	$	5,048	$	—
Level 1:
Mutual funds		1,107		—		—		1,107		1,107		—
U.S. agency securities		3,259		—		—		3,259		1,456		1,803
		4,366		—		—		4,366		2,563		1,803
Total	$	9,414	$	—	$	—	$	9,414	$	7,611	$	1,803

The maturities of our marketable securities generally range from within one to two years. Actual maturities could differ from contractual maturities due to call or prepayment provisions.

- Definition

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

+ References + Details

Litigation	12 Months Ended
Litigation	Dec. 31, 2019
Litigation [Abstract]
Litigation	Note 12 – Litigation (all dollar amounts in this section are expressed in thousands except for rates per device) We have multiple intellectual property infringement lawsuits pending in the United States District Court for the Eastern District of Texas, Tyler Division (“USDC”), and United States Court of Appeals for the Federal Circuit (“USCAFC”). VirnetX Inc. v. Cisco Systems, Inc. et al. (Case 6:10-CV-00417-LED) (“Apple I”) On August 11, 2010, we filed a complaint against Aastra USA. Inc. (“Aastra”), Apple Inc. (“Apple”), Cisco Systems, Inc. (“Cisco”), and NEC Corporation (“NEC”) the USDC in which we alleged that these parties infringe on certain of our patents (U.S. Patent Nos. 6,502,135, 7,418,504, 7,921,211 and 7,490,151). We sought damages and injunctive relief. The cases against each defendant were separated by the judge. Aastra and NEC agreed to sign license agreements with us, and we dropped all accusations of infringement against them. A jury in USDC decided that our patents were not invalid and rendered a verdict of non-infringement by Cisco on March 4, 2013. Our motion for a new Cisco trial was denied and the case against Cisco was closed. On November 6, 2012, a jury in the USDC awarded us over $368,000 for Apple’s infringement of four of our patents, plus daily interest up to the final judgment. Apple filed an appeal of the judgment to the USCAFC. On September 16, 2014, USCAFC affirmed the USDC jury’s finding that all four of our patents at issue are valid and confirmed the USDC jury’s finding of infringement of VPN on Demand under many of the asserted claims of our ‘135 and ‘151 patents, and the USDC’s decision to allow evidence about our license and royalty rates regarding the determination of damages. However, the USCAFC vacated the USDC jury’s damages award and some of the USDC’s claim construction with respect to parts of our ‘504 and ‘211 patents and remanded the damages award and determination of infringement with respect to FaceTime back to the USDC for further proceedings. On September 30, 2016, pursuant to the 2014 remand from the USCAFC, a jury in the USDC awarded us $302,400 for Apple’s infringement of four of our patents. On September 29, 2017, the USDC entered its final judgement, denied all of Apple’s post-trial motions, and granted all our post-trial motions, including our motion for willful infringement and enhanced the royalty rate during the willfulness period from $1.20 to $1.80 per device, and awarded us costs, certain attorneys’ fees, and prejudgment interest. The total amount in the final judgement was $439,700, including $302,400 (jury verdict), $41,300 (enhanced damages) and $96,000 (costs, fees and interest). On October 27, 2017 Apple filed its notice of appeal of this final judgement to the USCAFC. Apple filed its opening brief on March 19, 2018. We filed our response on April 4, 2018. On April 11, 2018, USCAFC designated Cases 18-1197-CB, Case 17-1368 and Case 17-1591 as companion cases and assigned to the same merits panel. Events and developments after this order are described below under VirnetX Inc. v. The Mangrove Partners (USCAFC Case 17-1368) (“Consolidated Appeal”). VirnetX Inc. v. Apple, Inc. (Case 6:12-CV-00855-LED) (“Apple II”) This case began on November 6, 2012, when we had filed a complaint against Apple in USDC in which we alleged that Apple infringed on certain of our patents, (U.S. Patent Nos. 6,502,135, 7,418,504, 7,921,211 and 7,490,151). We sought damages and injunctive relief. The accused products include the iPhone 5, iPod Touch 5th Generation, iPad 4^th Generation, iPad mini, and the latest Macintosh computers; These products were not included in the Apple I case because they were released after the Apple I case was initiated. Post-Trial Motions hearing was held on July 18, 2018. On August 31, 2018, the USDC entered a Final Judgment and issued its Memorandum Opinion and Order regarding post-trial motions, affirming the jury’s verdict of $502,600 and granting VirnetX motions for supplemental damages, a sunset royalty and the royalty rate of $1.20 per infringing iPhone, iPad and Mac products, pre-judgment and post-judgment interest and costs. On September 20, 2018, pursuant to a Court’s order, attorneys from VirnetX and Apple conferred and agreed, without dispute, to add an amount totaling $93,300 for Bill of Costs and Prejudgment Interest to the $502,600 jury verdict. The total amount in the final judgement in the Apple II case is now $595,900. Apple has filed a notice of appeal with the USCAFC in the Apple II case. On October 9, 2018, USCAFC accepted the notice and docketed it as Case No. 19-1050 - VirnetX Inc. v. Apple Inc. All subsequent events and developments in this case are described below under VirnetX Inc. v. Apple Inc. (USCAFC Case 19-1050) (“Apple II Appeal”). VirnetX Inc. v. The Mangrove Partners (USCAFC Case 17-1368) (“Consolidated Appeal”) On April 11, 2018, the USCAFC in an order designated the following appeals as companion cases and assigned to the same merits panel; ● VirnetX Inc. v. The Mangrove Partners (USCAFC Case 17-1368) On December 16, 2016, we filed appeals with the USCAFC, appealing the invalidity findings by the Patent Trial and Appeal Board (“PTAB”) in IPR2015-01046, and on December 20, 2016 for IPR2015-1047, involving our U.S. Patent Nos. 6,502,135, and 7,490,151. These appeals also involve Apple, and one of them involves Black Swamp IP, LLC. Oral arguments in this case were argued on January 8, 2019. On July 8, 2019, the USCAFC issued its opinion vacating and remanding both decisions. The court agreed with us that the PTAB misconstrued the patent claims, that many of the PTAB’s invalidity findings lacked substantial evidence, and that the PTAB Board abused its discretion in denying us the opportunity to file a motion for additional discovery as to the real party-in-interest issues. The underlying inter partes review (“IPR”) proceedings are currently pending before the PTAB. ● VirnetX Inc. v. Cisco Systems, Inc. (USCAFC Case 18-1197-CB) (Appeal of Apple I Case) On October 27, 2017 Apple appealed the Final Judgment entered on September 29, 2017 to the USCAFC. Oral arguments in this case were held on January 8, 2019. On January 15, 2019 the Court issued a Rule 36 order affirming the District Court Judgement. Apple filed a request for panel rehearing and rehearing en-banc in this matter on February 21, 2019. On March 12, 2019, the Court invited us to respond to Apple’s petition on or before March 26, 2019. We filed our response on March 22, 2019. On July 1, 2019 Apple filed a motion for leave to file a supplemental brief regarding the impact of the USCAFC’s decision in VirnetX Inc. v. Cisco Systems, Inc. (USCAFC Case 18-1751), issued on June 28, 2019 (described below). We filed a response to Apple’s motion and a contingent motion for leave to file a responsive supplemental brief on July 11, 2019. On July 17, 2019, the USCAFC granted both motions and ordered Apple’s and our supplemental briefs filed. On August 1, 2019, USCAFC issued an order denying Apple’s petition for panel and en banc rehearing. On August 7, 2019, Apple filed a motion to vacate the August 1, 2019 order and for leave to file a second request for panel rehearing and rehearing en-banc. On October 1, 2019, USCAFC issued an order denying Apple’s motion. Apple subsequently requested an extension for its deadline to petition for a writ of certiorari, and that deadline was extended until December 29, 2019. Apple filed a petition for a writ of certiorari with the U.S. Supreme Court, which was denied on February 24, 2020. Prior to the Supreme Court decision denying Apple’s Petition for Writ of Certiorari, on February 20, 2020, Apple filed a Rule 60(b) Motion for Relief from Judgment in the U.S. District Court (VirnetX Inc. v. Apple, 6:10-cv-00417) seeking relief from the Court’s September 29, 2017 Final Judgment. VirnetX filed a responsive brief in opposition on March 5, 2020. On March 13, 2020, the Company received payment of $454,034 from Apple, representing the previously announced final judgment with interest in this case. Apple has filed a motion in the USDC seeking to vacate the USDC's final judgment and has indicated that it will seek restitution of the payment if relief is awarded. The USDC has not ruled in this matter. ● VirnetX Inc. v. Apple Inc., Cisco Systems, Inc. (USCAFC Case 17-1591) On February 7, 2017, we filed appeals with the USCAFC, appealing the invalidity findings by the PTAB in inter-parties’ reexamination nos. 95/001,788, 95/001,789, and 95/001,856 related to our U.S. Patent Nos. 7,921,211 and 7,418,504. Oral arguments in this case were argued on January 8, 2019. On July 1, 2019 Apple filed a motion for leave to file a supplemental brief regarding the impact of the USCAFC’s decision in VirnetX Inc. v. Cisco Systems, Inc. (USCAFC Case 18-1751), issued on June 28, 2019 (described below). On August 1, 2019, the USCAFC issued an opinion in this case agreeing with us that the PTAB could not maintain two of those reexaminations (initiated by Apple) with respect to claims as to which there has been a prior “final decision” on patent validity entered by a federal court. The court instructed PTAB to terminate those reexamination proceedings with respect to claims 1-35 of the ‘504 patent and claims 36-59 of the ‘211 patent. The court affirmed PTAB’s invalidity findings with respect to the remaining patent claims. Apple filed a request for panel rehearing and rehearing en-banc in this matter on August 26, 2019. We filed a separate request for panel rehearing on September 3, 2019. Our request was denied on September 19, 2019, and Apple’s request was denied on October 11, 2019. All decisions are final in this case. VirnetX Inc. v. Apple Inc. (USCAFC Case 19-1050) (“Apple II Appeal”) On January 24, 2019 Apple filed its opening brief. We filed our response brief on March 1, 2019. Apple filed its reply brief on April 5, 2019. The oral arguments were heard on October 4, 2019. On November 22, 2019, the USCAFC issued an opinion affirming the district court’s findings that Apple is precluded from making certain invalidity arguments and that Apple infringed the ’135 and ’151 patents; reversing the district court’s finding that Apple infringed the ’504 and ’211 patents; and remanding the case for proceedings on damages. Apple sought panel and en banc rehearing, which the USCAFC denied on February 10, 2020. On February 22, 2020, USDC issued a scheduling order for the parties to brief the court about the need for a new trial for recalculating the damages. We filed our initial brief on February 28, 2020. All briefings have been completed. Court’s decision in the matter is awaited. VirnetX Inc. (USCAFC Case 17-2593) On September 22, 2017, we filed with the USCAFC appeals of the invalidity findings by the PTAB in IPR2016-00693 and IPR2016-00957 involving our U.S. Patent Nos. 7,418,504 and 7,921,211. The briefing in these appeals has not taken place. The entity that initiated the IPRs, Black Swamp IP, LLC, indicated on October 18, 2017, that it would not participate in the appeals. On November 27, 2017, the USPTO indicated that it would intervene in the appeals. On January 19, 2018, the USCAFC stayed these appeals pending the USCAFC’s decision in Case 17-1591. On October 25, 2019, we and the USPTO filed a joint request that the deadline to inform the USCAFC how these appeals should proceed be extended until November 1, 2019. On November 15, 2019, we and the USPTO requested that the USCAFC stay this appeal pending resolution of any petition for rehearing in Arthrex, Inc. v. Smith & Nephew, Inc., No. 2018-2140. The USCAFC denied the stay request on November 27, 2019. On January 6, 2020, we filed a motion to vacate and remand in light of Arthrex, Inc. v. Smith & Nephew, Inc., 941 F.3d 1320 (Fed. Cir. 2019), which was granted on February 27, 2020. VirnetX Inc. v. Cisco Systems, Inc. (USCAFC Case 18-1751) On March 30, 2018, we filed with the USCAFC an appeal of the invalidity findings by the PTAB in inter-partes reexamination no. 95/001,851 involving our U.S. Patent No. 7,418,504. Oral arguments in this case were held on June 4, 2019. On June 28, 2019, the USCAFC issued its opinion vacating the PTAB’s invalidity findings with respect to claims 5, 12, and 13 and remanding to the PTAB for further proceedings. The court affirmed the PTAB’s invalidity findings with respect to the remaining patent claims. Cisco filed a request for panel rehearing and rehearing en-banc in this matter on August 12, 2019. Cisco’s request was denied on October 1, 2019. VirnetX Inc. v. Cisco Systems, Inc. (USCAFC Case 19-1043) On October 1, 2018, we filed with the USCAFC an appeal of the invalidity findings by the PTAB in inter-partes reexamination no. 95/001,746 involving our U.S. Patent No. 6,839,759. We filed our opening brief on March 15, 2019. Cisco filed its response brief on June 19, 2019. We filed our reply brief on August 14, 2019. Cisco filed a motion to submit a sur-reply brief on August 26, 2019, which we opposed. On September 27, 2019, the USCAFC issued an order deferring resolution of Cisco’s motion for the merits panel. Oral argument was held on January 8, 2020. On January 21, 2020, the USCAFC issued a Rule 36 judgment affirming the PTAB’s decision. VirnetX Inc. v. Cisco Systems, Inc. (USCAFC Case 19-1671) On March 18, 2018, we filed with the USCAFC an appeal of the invalidity findings by the PTAB in inter-partes reexamination no. 95/001,679 involving our U.S. Patent No. 6,502,135. We filed a motion to remand on August 23, 2019, which the USCAFC denied on October 1, 2019, directing the parties to address the issues in the merits briefs. Our opening brief is currently due on November 12, 2019. On November 7, 2019, we filed another motion to vacate and remand in light of Arthrex. The USPTO intervened and opposed the remand. The USCAFC granted our motion on January 24, 2020. VirnetX Inc. v. Cisco Systems, Inc. (USCAFC Case 19-1725) On March 29, 2019, we filed with the USCAFC an appeal of the invalidity findings by the PTAB in inter-partes reexamination no. 95/001,792 involving our U.S. Patent No. 7,188,180. We filed a motion to remand on September 10, 2019. We filed a supplemental motion to remand in light of Arthrex on November 22, 2019, which the USCAFC granted on January 24, 2020. Cisco filed a petition for panel and en banc rehearing on February 24, 2020, which remains pending. One or more potential intellectual property infringement claims may also be available to us against certain other companies who have the resources to defend against any such claims. Although we believe these potential claims are likely valid, commencing a lawsuit can be expensive and time-consuming, and there is no assurance that we could prevail on such potential claims if we made them. In addition, bringing a lawsuit may lead to potential counterclaims which may distract our management and our other resources, including capital resources, from efforts to successfully commercialize our products. Currently, we are not a party to any other pending legal proceedings and are not aware of any proceeding threatened or contemplated against us.

Quarterly Financial Information (unaudited)

12 Months Ended

Dec. 31, 2019

Quarterly Financial Information (unaudited) [Abstract]

Quarterly Financial Information (unaudited)

Note 13 − Quarterly Financial Information (unaudited)

	First			Second			Third			Fourth
				(in thousands except per share)
2019
Revenue	$	8		$	38		$	4		$	35
Loss from operations	$	(5,634	)	$	(4,552	)	$	(4,976	)	$	(4,503	)
Net loss	$	(5,608	)	$	(4,130	)	$	(4,956	)	$	(4,485	)
Basic and diluted (loss) per common share	$	(.08	)	$	(.06	)	$	(.07	)	$	(.07	)

	First			Second			Third			Fourth
				(in thousands except per share)
2018
Revenue	$	6		$	16		$	7		$	34
Loss from operations	$	(7,608	)	$	(6,462	)	$	(4,948	)	$	(6,439	)
Net loss	$	(7,605	)	$	(6,450	)	$	(4,934	)	$	(6,417	)
Basic and diluted (loss) per common share	$	(0.13	)	$	(0.10	)	$	(0.08	)	$	(0.09	)

Effects of Adopting ASU Topic 842 - Leases	12 Months Ended
Effects of Adopting ASU Topic 842 - Leases	Dec. 31, 2019
Effects of Adopting ASU Topic 842 - Leases [Abstract]
Effects of Adopting ASU Topic 842 - Leases	Note 14 – Effects of Adopting ASU Topic 842 - Leases We determine if an arrangement is a lease at inception. Operating lease ROU assets are included in Prepaid expense and other assets on the Consolidated Balance Sheet as of December 31, 2019. ROU assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. ROU assets and lease liabilities are recognized at the commencement date based on the present value of lease payments over the lease term. We lease office space under an operating lease which expires on October 31, 2021. We also entered an operating lease for a facility used for corporate promotional and marketing purposes which was prepaid in full in a prior year and expires in 2024. As described under New Accounting Pronouncements above, we adopted ASU Topic 842 - Leases effective January 1, 2019. As a result of the adoption, on January 1, 2019 we reclassified $385 of prepaid lease payments for the promotional and marketing facility from current assets to non-current assets. At January 1, 2019 we recorded a ROU asset and lease liability of $45 for the office lease with a balance of $97 at December 31, 2019. Adoption of the ASU had no impact on the Consolidated Statement of Operations.

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	Note 15 – Subsequent Events Between January 1, 2020 and February 21, 2020, we sold 1,049,382 shares of common stock under the ATM program. The average sales price per common shares sold was $4.41 and the aggregate proceeds from the sales totaled $4,627. Sales commissions, fees and other costs associated with these ATM transactions totaled $139. Between January 1, 2020 and March 10, 2020 our employees exercised 151,308 options. On March 13, 2020, the Company received payment of $454,034 from Apple, Inc. ("Apple"), representing the previously announced final judgment with interest in the VirnetX Inc. v. Cisco Systems, Inc. et al (Case 6:10-CV-00417-LED) litigation ("Apple I"). (See Note 12 - Litigation)

Summary of Significant Accounting Policies (Policies)	12 Months Ended
Summary of Significant Accounting Policies (Policies)	Dec. 31, 2019
Summary of Significant Accounting Policies [Abstract]
Use of Estimates	Use of Estimates We prepare our consolidated financial statements in accordance with accounting principles generally accepted in the U.S. (“U.S. GAAP”). In doing so, we have to make estimates and assumptions that affect our reported amounts of assets, liabilities, revenues, and expenses, as well as related disclosure of contingent assets and liabilities. In some cases, we could reasonably have used different accounting policies and estimates. In some cases, changes in the accounting estimates are reasonably likely to occur from period to period. Accordingly, actual results could differ materially from our estimates. To the extent that there are material differences between these estimates and actual results, our financial condition or results of operations will be affected. We base our estimates on past experience and other assumptions that we believe are reasonable under the circumstances, and we evaluate these estimates on an ongoing basis. We refer to accounting estimates of this type as critical accounting policies and estimates, which we discuss further below. We have reviewed our critical accounting policies and estimates with the audit committee of our board of directors.
Basis of Consolidation	Basis of Consolidation The consolidated financial statements include the accounts of VirnetX Holding Corporation and our wholly owned subsidiaries. All intercompany balances and transactions have been eliminated.
Leases	Leases The Company determines if an arrangement is a lease at inception in accordance with Accounting Standards Codification (“ASC”) Topic 842. Operating lease right-of-use (“ROU”) assets are included in Prepaid expense, and other assets on the Consolidated Balance Sheet. ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. ROU assets and lease liabilities are recognized at the commencement date based on the present value of lease payments over the lease term. (See Note 14)
Revenue Recognition	Revenue Recognition We derive our revenue from patent licensing. The timing and amount of revenue recognized from each licensee depends upon a variety of factors, including the specific terms of each agreement and the nature of the deliverables and obligations. Such agreements may be complex and include multiple elements. These agreements may include, without limitation, elements related to the settlement of past patent infringement liabilities, up-front and non-refundable license fees for the use of patents, patent licensing royalties on covered products sold by licensees, and the compensation structure and ownership of intellectual property rights associated with contractual technology development arrangements. We account for revenue in accordance with Accounting Standards Update (“ASU”) No.2014-09, Revenue from Contracts with Customers (“Topic 606”), which we adopted on January 1, 2018 using the modified-retrospective method. Under Topic 606 a performance obligation is a promise in a contract to transfer a distinct good or service to the customer. A contract’s transaction price is allocated to each distinct performance obligation and recognized as revenue when, or as, the performance obligation is satisfied. Our revenue arrangements may consist of multiple-element arrangements, with revenue for each unit of accounting recognized as the product or service is delivered to the customer. With the licensing of our patents, performance obligations are generally satisfied at a point in time as work is complete and our patent rights are transferred to our customers. We generally have no further obligation to our customers regarding our technology. Certain contracts may require our customers to enter into a hosting arrangement with us and for these arrangements’ revenue is recognized over time, generally over the life of the servicing contract.
Contingent Gains	Contingent Gains We recognize gain contingencies in accordance with ASC 450-30-25 which prohibits recognition of contingent gains until realized. Accordingly, we do not record contingent gains ahead of such realization. Management generally considers any such gains as realized only upon the collection of cash.
Cash and Cash Equivalents	Cash and Cash Equivalents We consider all highly liquid investments purchased with original maturities of three months or less at the date of purchase to be cash equivalents. Our cash and cash equivalents are not subject to significant interest rate risk due to the short maturities of these investments.
Prepaid Expenses and Other Current Assets	Prepaid Expenses and Other Current Assets Prepaid Expense and Other Current Assets on the consolidated balance sheet at December 31, 2018 includes the current portion of prepaid rent for a facility lease for corporate promotional and marketing purposes, and this balance is included in ROU assets as of December 31, 2019 (see Note 14 - Effects of Adopting ASU Topic 842 – Leases, below). In a prior year, the Company prepaid $4,000 which is being amortized over the remaining balance of the lease. The unamortized non-current portion of the prepayment is included in Prepaid Expenses-Non-current on the consolidated balance sheet.
Investments	Investments Investments are classified as available-for-sale and are recorded at fair market value. Unrealized gains and losses are reported as other comprehensive income. Realized gains and losses are recorded in income in the period they are realized using specific identification of each security’s cost basis. We invest our excess cash primarily in highly liquid debt instruments including corporate, government and federal agency securities, with contractual maturities less than two years. By policy, we limit the amount of credit exposure to any one issuer.
Property and Equipment	Property and Equipment Property and equipment are stated at historical cost, less accumulated depreciation and amortization. Depreciation and amortization are computed using the accelerated and straight-line methods over the estimated useful lives of the assets, which range from five to seven years. Repair and maintenance costs are charged to expense as incurred.
Concentration of Credit Risk and Other Risks and Uncertainties	Concentration of Credit Risk and Other Risks and Uncertainties Our cash and cash equivalents are primarily maintained at two major financial institutions in the United States. Deposits held with these financial institutions may exceed the amount of insurance provided on such deposits. A portion of those balances are insured by the Federal Deposit Insurance Corporation, or FDIC. During the year ended December 31, 2019 and 2018, we had, at times, funds that were uninsured. We do not believe that we are subject to any unusual financial risk beyond the normal risk associated with commercial banking relationships. We have not experienced any losses on our deposits of cash and cash equivalents.
Fair Value	Fair Value The carrying amounts of our financial instruments, including cash equivalents, accounts payable, and accrued liabilities, approximate fair value because of their generally short maturities.
Intangible Assets	Intangible Assets We record intangible assets at cost, less accumulated amortization. Amortization of intangible assets is provided over their estimated useful lives, which can range from 3 to 15 years, on either a straight-line basis or as revenue is generated by the assets.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets We identify and record impairment losses on long-lived assets used in operations when events and changes in circumstances indicate that the carrying amount of an asset might not be recoverable, but not less than annually. Recoverability is measured by comparison of the anticipated future net undiscounted cash flows to the related assets’ carrying value. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the projected discounted future net cash flows arising from the asset.
Research and Development	Research and Development Research and development costs include expenses paid to outside development consultants and compensation related expenses for our engineering staff. Research and development costs are expensed as incurred.
Income Taxes	Income Taxes We account for income taxes using the asset and liability method. The asset and liability method requires the recognition of deferred tax assets and liabilities for expected future tax consequences of temporary differences that currently exist between the tax basis and financial reporting basis of our assets and liabilities. We calculate current and deferred tax provisions based on estimates and assumptions that could differ from actual results reflected on the income tax returns filed during the following years. Adjustments based on filed returns are recorded when identified in the subsequent years. The effect on deferred taxes for a change in tax rates is recognized in income in the period that the tax rate change is enacted. In assessing our deferred tax assets, we consider whether it is more likely than not that all or some portion of the deferred tax assets will not be realized. A valuation allowance is provided for deferred income tax assets when, in our judgment, based upon currently available information and other factors, it is more likely than not that all or a portion of such deferred income tax assets will not be realized. The determination of the need for a valuation allowance is based on an on-going evaluation of current information including, among other things, historical operating results, estimates of future earnings in different taxing jurisdictions and the expected timing of the reversals of temporary differences. We believe the determination to record a valuation allowance to reduce a deferred income tax asset is a significant accounting estimate because it is based, among other things, on an estimate of future taxable income in the United States and certain other jurisdictions, which is susceptible to change and may or may not occur, and because the impact of adjusting a valuation allowance may be material. In determining when to release the valuation allowance established against our net deferred income tax assets, we consider all available evidence, both positive and negative. Consistent with our policy, and because of our history of operating losses, we do not currently recognize the benefit of all of our deferred tax assets, including tax loss carry forwards, that may be used to offset future taxable income. We continually assess our ability to generate sufficient taxable income during future periods in which our deferred tax assets may be realized. If and when we believe it is more likely than not that we will recover our deferred tax assets, we will reverse the valuation allowance as an income tax benefit in our statements of operations. We account for our uncertain tax positions in accordance with U.S. GAAP. The U.S. GAAP method of accounting for uncertain tax positions utilizes a two-step approach to evaluate tax positions. Step one, recognition, requires evaluation of the tax position to determine if based solely on technical merits it is more likely than not to be sustained upon examination. Step two, measurement, is addressed only if a position is more likely than not to be sustained. In step two, the tax benefit is measured as the largest amount of benefit, determined on a cumulative probability basis, which is more likely than not to be realized upon ultimate settlement with tax authorities. If a position does not meet the more likely than not threshold for recognition in step one, no benefit is recorded until the first subsequent period in which the more likely than not standard is met, the issue is resolved with the taxing authority, or the statute of limitations expires. Positions previously recognized are derecognized when we subsequently determine the position no longer is more likely than not to be sustained. Evaluation of tax positions, their technical merits, and measurements using cumulative probability are highly subjective management estimates. Actual results could differ materially from these estimates.
Stock-Based Compensation	Stock-Based Compensation We account for stock-based compensation using the fair value recognition method in accordance with U.S. GAAP. We recognize these compensation costs on a straight-line basis over the requisite service period of the award, which is generally the vesting term of 4 years. We do not estimate the forfeiture rate and recognize forfeitures, if any, when they occur. See Note 6 - Stock-Based Compensation below for additional information concerning our share-based compensation awards. In addition, as required we record stock-based compensation expense for awards granted to non-employees at fair value of the consideration received or the fair value of the equity instruments issued as they vest over the performance period.
Earnings per Share	Earnings per Share Basic earnings per share are computed by dividing earnings available to common stockholders by the weighted average number of outstanding common shares during the period. Diluted earnings per share is computed by dividing net income by the weighted average number of shares outstanding during the period increased to include the number of additional shares of common stock that would have been outstanding if the potentially dilutive securities had been issued. During 2019, and 2018 we incurred losses; therefore, the effect of any common stock equivalent would be anti-dilutive during these periods.
New Accounting Pronouncements	New Accounting Pronouncements In December 2019 the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2019-12 Income Taxes (Topic 740). The amendments in this ASU simplify the accounting for income taxes by removing certain exceptions to the general principles in Topic 740. The amendments also improve consistent application of and simplify GAAP for other areas of Topic 740 by clarifying and amending existing guidance. The amendments in this ASU are effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. We are currently evaluating the impact, if any this ASU will have on our consolidated financial statements and related disclosures. In August 2018 the FASB issued ASU 2018-13 - Fair Value Measurement (Topic 820). The FASB is issuing the amendments in this ASU as part of the disclosure framework project. On March 4, 2014, the Board issued a proposed FASB Concepts Statement, Conceptual Framework for Financial Reporting—Chapter 8: Notes to Financial Statements, which the Board finalized on August 28, 2018. The disclosure framework project’s objective and primary focus are to improve the effectiveness of disclosures in the notes to financial statements by facilitating clear communication of the information required by GAAP that is most important to users of each entity’s financial statements. The amendments in this ASU are effective for all entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. We will adopt this guidance on January 1, 2020 and expect this guidance will have no material impact on our financial position and statement of operations. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses (“Topic 326”). The purpose of this ASU is to require a financial asset measured at amortized cost basis to be presented at the net amount expected to be collected. Credit losses relating to available-for-sale debt securities should be recorded through an allowance for credit losses. This ASU is effective for interim and annual reporting periods beginning after December 15, 2019. We will adopt this guidance on January 1, 2020 and expect this guidance will have no material impact on our financial position and statement of operations. In February 2016, FASB issued ASU No. 2016-02, Leases (Topic 842) as amended and supplemented by subsequent ASU’s, (“ASU 2016-02”). ASU 2016-02 requires an entity to recognize ROU assets and lease liabilities on its balance sheet and disclose key information about leasing arrangements. For public companies, ASU 2016-02 is effective for annual reporting periods beginning after December 15, 2018, including interim periods within that reporting period, and requires a modified retrospective adoption, with early adoption permitted. We adopted this ASU on January 1, 2019 which had no impact on our consolidated statements of operations. In May 2014, the FASB issued ASU No. 2014-09 Revenue from Contracts with Customers (“Topic 606”). As amended, Topic 606 supersedes prior revenue recognition requirements including most industry-specific revenue recognition guidance. On January 1, 2018 we adopted this standard using the modified retrospective method which resulted in a $2,500 decrease in accumulated deficit and a $2,500 decrease in deferred revenue in our consolidated balance sheet.

Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2019

Property and Equipment [Abstract]

Classes of Property and Equipment

Our major classes of property and equipment were as follows:

	December 31
	2019			2018
Office furniture	$	79		$	79
Computer equipment		81			67
Total		160			146
Less accumulated depreciation		(144	)		(137	)
Total property and equipment, net	$	16		$	9

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2019

Stock-Based Compensation [Abstract]

Information about Stock Options Outstanding

The following tables summarize information about stock options and RSUs outstanding at December 31, 2019:

Options Outstanding								Options Vested and Exercisable
Range of Exercise Prices	Number Outstanding		Weighted Average Remaining Contractual Life (Years)		Weighted Average Exercise Price			Number Exercisable		Weighted Average Remaining Contractual Life (Years)		Weighted Average Exercise Price
$ 2.35 - 6.95		4,376,396		7.08		$	4.29		2,826,062		6.48		$	4.31
$ 14.52 - 35.25		1,253,625		2.71		$	23.16		1,253,625		2.71		$	23.16
		5,630,021		6.11		$	8.49		4,079,687		5.32		$	10.10

Stock Option Activity

The following tables summarize activity under the Plan for the indicated periods:

	Options
	Number of Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value
Outstanding at December 31, 2017		5,138,066		$	8.41		—	$	—
Options granted		1,095,000			3.52		—		—
Options exercised		(117,229	)		1.15		—		—
Options cancelled		(117,000	)		5.34		—		—
Outstanding at December 31, 2018		5,998,837		$	7.72		—	$	—
Options granted		345,000			6.06		—		—
Options exercised		(663,816	)		1.23		—		—
Options cancelled		(50,000	)		4.95		—		—
Outstanding at December 31, 2019		5,630,021		$	8.49		6.11	$	516
Options exercisable at December 31, 2019		4,079,687		$	10.10		5.32	$	314

	RSUs
	Number of RSUs			Weighted Average Grant Date Fair Value		Aggregate Intrinsic Value
Outstanding at December 31, 2017		469,661		$	5.19	$	—
RSUs granted		246,663			3.26		—
RSUs vested		(211,330	)		6.19		—
Outstanding at December 31, 2018		504,994		$	3.83	$	—
RSUs granted		229,996			6.06		—
RSUs vested		(207,334	)		4.07		—
RSUs cancelled		(29,167	)		4.65
Outstanding at December 31, 2019		498,489		$	4.71	$	86

Stock-Based Compensation by Type of Award

Stock-based compensation expense is included in general and administrative expense for each period as follows:

Stock-Based Compensation by Type of Award	Year Ended December 31, 2019		Year Ended December 31, 2018
Stock options	$	2,756	$	2,926
RSUs		955		1,129
Total stock-based compensation expense	$	3,711	$	4,055

Fair Value Assumptions

The fair value of each option grant was estimated on the date of grant using the Black-Scholes option pricing model using the following weighted average assumptions:

	Year Ended December 31, 2019			Year Ended December 31, 2018
Expected stock price volatility		92.34	%		85.26	%
Risk-free interest rate		2.09	%		2.73	%
Expected life term	6.14 years			6.02 years
Expected dividends		0	%		0	%

Earnings Per Share (Tables)

12 Months Ended

Dec. 31, 2019

Earnings Per Share [Abstract]

Basic and Diluted Loss Per Share Calculations

The table below sets forth the basic and diluted loss per share calculations:

	2019			2018
Net loss	$	(19,180	)		(25,406	)
Basic and diluted weighted average number of shares outstanding		68,564			62,986
Basic and diluted loss per share	$	(0.28	)		(0.40	)

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2019

Income Taxes [Abstract]

Income Tax Benefit (Provision)

The income tax benefit (provision) is comprised of the following:

	Year Ended December 31, 2019		Year Ended December 31, 2018
Current:
Federal	$	—	$	—
State		393		(3	)
Foreign		—		—
		393		(3	)
Deferred:
Federal		—		—
State		—		—
Total income tax provision	$	393	$	(3	)

Effective Income Tax Rate Reconciliation

A reconciliation of the United States federal statutory income tax rate to our effective income tax rate is as follows:

	Year Ended December 31, 2019			Year Ended December 31, 2018
United States federal statutory rate		21.00	%		21.00	%
State taxes, net of federal benefit		1.99	%		(0.01	)%
Valuation allowance		(21.96	)%		(24.33	)%
Accounting method change - ASC 606		—			2.07	%
R&D Credit		1.34	%		1.53	%
Other		(0.38	)%		(0.27	)%
Effective income tax rate		1.99	%		(0.01	)%

Deferred Tax Assets and Liabilities

Deferred tax assets (liabilities) consist of the following:

	As of December 31, 2019			As of December 31, 2018
Deferred tax assets:
Reserves and accruals	$	62		$	45
Research and development credits and other credits		1,730			1,635
Net operating loss carry forward		27,907			25,733
Stock based compensation		8,402			8,857
Other		11			26
Total deferred tax assets		38,112			36,296

Valuation allowance		(38,112	)		(36,296	)
Deferred tax assets after valuation allowance		—			—

Total deferred tax liability		—			—

Net deferred tax assets (liabilities)	$	—		$	—

Reconciliation of Provision for Uncertain Tax Position

Reconciliation of provision for uncertain tax position discussed above:

	Year Ended December 31, 2019			Year Ended December 31, 2018
Balance at the beginning of the year	$	316		$	316
Additions based on tax positions related to the current year		—			—
Additions for tax positions of prior years		—			—
Settlements		—			—
Lapse of applicable statute of limitations		(316	)		—
Balance at the end of the year	$	—		$	316

Fair Value Measurement (Tables)

12 Months Ended

Dec. 31, 2019

Fair Value Measurement [Abstract]

Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value of Financial Assets

The following table shows the adjusted cost, gross unrealized gains, gross unrealized losses and fair value of our financial assets as of December 31, 2019 and 2018 (in thousands):

	December 31, 2019
	Adjusted Cost		Unrealized Gains		Unrealized Losses		Fair Value		Cash and Cash Equivalents		Investments Available for Sale
Cash	$	2,076	$	—	$	—	$	2,076	$	2,076	$	—
Level 1:
Mutual funds		613		—		—		613		613		—
U.S. agency securities		2,837		3		—		2,840		446		2,394
		3,450		3		—		3,453		1,059		2,394
Total	$	5,526	$	3	$	—	$	5,529	$	3,135	$	2,394

	December 31, 2018
	Adjusted Cost		Unrealized Gains		Unrealized Losses		Fair Value		Cash and Cash Equivalents		Investments Available for Sale
Cash	$	5,048	$	—	$	—	$	5,048	$	5,048	$	—
Level 1:
Mutual funds		1,107		—		—		1,107		1,107		—
U.S. agency securities		3,259		—		—		3,259		1,456		1,803
		4,366		—		—		4,366		2,563		1,803
Total	$	9,414	$	—	$	—	$	9,414	$	7,611	$	1,803

Quarterly Financial Information (unaudited) (Tables)

12 Months Ended

Dec. 31, 2019

Quarterly Financial Information (unaudited) [Abstract]

Quarterly Financial Information

	First			Second			Third			Fourth
				(in thousands except per share)
2019
Revenue	$	8		$	38		$	4		$	35
Loss from operations	$	(5,634	)	$	(4,552	)	$	(4,976	)	$	(4,503	)
Net loss	$	(5,608	)	$	(4,130	)	$	(4,956	)	$	(4,485	)
Basic and diluted (loss) per common share	$	(.08	)	$	(.06	)	$	(.07	)	$	(.07	)

	First			Second			Third			Fourth
				(in thousands except per share)
2018
Revenue	$	6		$	16		$	7		$	34
Loss from operations	$	(7,608	)	$	(6,462	)	$	(4,948	)	$	(6,439	)
Net loss	$	(7,605	)	$	(6,450	)	$	(4,934	)	$	(6,417	)
Basic and diluted (loss) per common share	$	(0.13	)	$	(0.10	)	$	(0.08	)	$	(0.09	)

Formation and Business of the Company (Details) - Patents [Member]	Dec. 31, 2019 Patent
Formation and Business of the Company Disclosure [Abstract]
Number of patents and pending applications	194
U.S. [Member]
Formation and Business of the Company Disclosure [Abstract]
Number of patents and pending applications	70
Foreign [Member]
Formation and Business of the Company Disclosure [Abstract]
Number of patents and pending applications	124

Summary of Significant Accounting Policies (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) Institution	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid lease payments for promotional and marketing facility		$ 4,000
Concentration of Credit Risk and Others Risks and Uncertainties [Abstract]
Number of financial institutions holding company's cash \| Institution	2
Stock-Based Compensation [Abstract]
Option vesting term	4 years
New Accounting Pronouncements [Abstract]
Balance	$ (5,628)	(9,888)	$ (1,553)
Minimum [Member]
Property and Equipment [Abstract]
Useful lives	5 years
Intangible Assets [Abstract]
Estimated useful lives	3 years
Maximum [Member]
Property and Equipment [Abstract]
Useful lives	7 years
Intangible Assets [Abstract]
Estimated useful lives	15 years
Accumulated Deficit [Member]
New Accounting Pronouncements [Abstract]
Balance	$ 217,602	$ 198,422	175,516
Highly Liquid Debt Investments [Member] \| Maximum [Member]
Investments [Abstract]
Contractual maturities of investment securities	2 years
ASU 2014-09 [Member]
New Accounting Pronouncements [Abstract]
Balance			(2,500)
ASU 2014-09 [Member] \| Deferred Revenue [Member]
New Accounting Pronouncements [Abstract]
Balance			(2,500)
ASU 2014-09 [Member] \| Accumulated Deficit [Member]
New Accounting Pronouncements [Abstract]
Balance			$ (2,500)

Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property and Equipment [Abstract]
Property and equipment, gross	$ 160	$ 146
Less accumulated depreciation	(144)	(137)
Property and equipment, net	16	9
Depreciation expense	7	18
Office Furniture [Member]
Property and Equipment [Abstract]
Property and equipment, gross	79	79
Computer Equipment [Member]
Property and Equipment [Abstract]
Property and equipment, gross	$ 81	$ 67

Commitments, Contingencies and Related Party Transactions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Commitments, Contingencies and Related Party Transactions [Abstract]
Rent expense	$ 56	$ 56
Total future minimum rents due	102
Future minimum rents due in 2020	56
Future minimum rents due in 2021	$ 46
Offices [Member]
Commitments, Contingencies and Related Party Transactions [Abstract]
Operating lease, expiration date	Oct. 31, 2021
K2 Investment Fund LLC [Member] \| Aircraft [Member]
Commitments, Contingencies and Related Party Transactions [Abstract]
Rental fees incurred for use of aircraft	$ 1,790	$ 1,590
Term of lease	12 months
Rate of aircraft lease (in dollars per flight hour)	$ 8
Term of notice for cancellation of lease	30 days

Stock Plan (Details)	12 Months Ended
Stock Plan (Details)	Dec. 31, 2019 shares
Stock Plan [Abstract]
Vesting period	4 years
2013 Plan [Member]
Stock Plan [Abstract]
Shares available for grant (in shares)	1,208,070
2013 Plan [Member] \| Stock Options [Member]
Stock Plan [Abstract]
Vesting period	4 years
Term of award	10 years
2013 Plan [Member] \| Stock Options [Member] \| Named Executive Officers [Member] \| Minimum [Member]
Stock Plan [Abstract]
Exercise price of option granted as percentage of fair market value of shares at date of grant	100.00%
2013 Plan [Member] \| Stock Options [Member] \| 10% Shareholder [Member] \| Minimum [Member]
Stock Plan [Abstract]
Exercise price of option granted as percentage of fair market value of shares at date of grant	110.00%
2013 Plan [Member] \| Incentive Stock Options [Member] \| Minimum [Member]
Stock Plan [Abstract]
Exercise price of option granted as percentage of fair market value of shares at date of grant	100.00%
2013 Plan [Member] \| Nonqualified Stock Options [Member] \| Minimum [Member]
Stock Plan [Abstract]
Exercise price of option granted as percentage of fair market value of shares at date of grant	85.00%
2013 Plan [Member] \| Restricted Stock Purchase Rights ("RSU") [Member]
Stock Plan [Abstract]
Vesting period	4 years

Stock-Based Compensation, Information about Stock Options Outstanding (Details) - Stock Options [Member]	12 Months Ended
	Dec. 31, 2019 $ / shares shares
Information about Stock Options Outstanding [Abstract]
Options outstanding, number outstanding (in shares) \| shares	5,630,021
Options outstanding, weighted average remaining contractual life	6 years 1 month 10 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 8.49
Options vested and exercisable, number exercisable (in shares) \| shares	4,079,687
Options vested and exercisable, weighted average remaining contractual life	5 years 3 months 25 days
Options vested and exercisable, weighted average exercise price (in dollars per share)	$ 10.10
$2.35 - 6.95 [Member]
Information about Stock Options Outstanding [Abstract]
Exercise price range, lower range limit (in dollars per share)	2.35
Exercise price range, upper range limit (in dollars per share)	$ 6.95
Options outstanding, number outstanding (in shares) \| shares	4,376,396
Options outstanding, weighted average remaining contractual life	7 years 29 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 4.29
Options vested and exercisable, number exercisable (in shares) \| shares	2,826,062
Options vested and exercisable, weighted average remaining contractual life	6 years 5 months 23 days
Options vested and exercisable, weighted average exercise price (in dollars per share)	$ 4.31
$14.52 - 35.25 [Member]
Information about Stock Options Outstanding [Abstract]
Exercise price range, lower range limit (in dollars per share)	14.52
Exercise price range, upper range limit (in dollars per share)	$ 35.25
Options outstanding, number outstanding (in shares) \| shares	1,253,625
Options outstanding, weighted average remaining contractual life	2 years 8 months 16 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 23.16
Options vested and exercisable, number exercisable (in shares) \| shares	1,253,625
Options vested and exercisable, weighted average remaining contractual life	2 years 8 months 16 days
Options vested and exercisable, weighted average exercise price (in dollars per share)	$ 23.16

Stock-Based Compensation, Summary of Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation [Abstract]
Per share market price of common stock on last trading day of year (in dollars per share)	$ 3.80
Proceeds from exercise of options	$ 816	$ 135
Stock Options [Member]
Options, number of shares [Roll Forward]
Outstanding, beginning of period (in shares)	5,998,837	5,138,066
Options granted (in shares)	345,000	1,095,000
Options exercised (in shares)	(663,816)	(117,229)
Options cancelled (in shares)	(50,000)	(117,000)
Outstanding, end of period (in shares)	5,630,021	5,998,837
Options exercisable, end of period (in shares)	4,079,687
Options, weighted average exercise price [Roll Forward]
Outstanding, beginning of period (in dollars per share)	$ 7.72	$ 8.41
Options granted (in dollars per share)	6.06	3.52
Options exercised (in dollars per share)	1.23	1.15
Options cancelled (in dollars per share)	4.95	5.34
Outstanding, end of period (in dollars per share)	8.49	$ 7.72
Options exercisable, end of period (in dollars per share)	$ 10.10
Options, additional disclosures [Abstract]
Options outstanding, weighted average remaining contractual life	6 years 1 month 10 days
Options exercisable, weighted average remaining contractual life	5 years 3 months 25 days
Options outstanding, aggregate intrinsic value	$ 516
Options exercisable, aggregate intrinsic value	314
Share-based Compensation [Abstract]
Proceeds from exercise of options	816	$ 135
Total intrinsic value of options exercised	$ 2,473	$ 46
Restricted Stock Units (RSUs) [Member]
RSUs, number of RSUs [Roll Forward]
Outstanding, beginning of period (in shares)	504,994	469,661
RSUs granted (in shares)	229,996	246,663
RSUs vested (in shares)	(207,334)	(211,330)
RSUs cancelled (in shares)	(29,167)
Outstanding, end of period (in shares)	498,489	504,994
RSUs, weighted average grant date fair value [Abstract]
Outstanding, beginning of period (in dollars per share)	$ 3.83	$ 5.19
RSUs granted (in dollars per share)	6.06	3.26
RSUs vested (in dollars per share)	4.07	6.19
RSUs cancelled (in dollars per share)	4.65
Outstanding, end of period (in dollars per share)	$ 4.71	$ 3.83
RSUs, aggregate intrinsic value [Abstract]
Outstanding, end of period	$ 86	$ 0	$ 0

Stock-Based Compensation, Stock-Based Compensation by Type of Award (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation [Abstract]
Stock-based compensation expense	$ 3,711	$ 4,055
General and Administrative Expense [Member]
Share-based Compensation [Abstract]
Stock-based compensation expense	3,711	4,055
Stock Options [Member]
Compensation cost not yet recognized [Abstract]
Unrecognized stock-based compensation expense expected to be recognized related to non-vested stock options	$ 4,801
Weighted-average period for recognition of unrecognized stock-based compensation expense	2 years 1 month 17 days
Stock Options [Member] \| General and Administrative Expense [Member]
Share-based Compensation [Abstract]
Stock-based compensation expense	$ 2,756	2,926
RSUs [Member]
Compensation cost not yet recognized [Abstract]
Unrecognized stock-based compensation expense expected to be recognized related to non-vested RSUs	$ 1,882
Weighted-average period for recognition of unrecognized stock-based compensation expense	2 years 3 months 29 days
RSUs [Member] \| General and Administrative Expense [Member]
Share-based Compensation [Abstract]
Stock-based compensation expense	$ 955	$ 1,129

Stock-Based Compensation, Fair Value Assumptions Used (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Fair value assumptions used in estimating fair value of each option grant [Abstract]
Expected stock price volatility	92.34%	85.26%
Risk-free interest rate	2.09%	2.73%
Expected life term	6 years 1 month 20 days	6 years 7 days
Expected dividends	0.00%	0.00%
Options granted, weighted average grant date fair value (in dollars per share)	$ 4.63	$ 2.58

Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Calculation of basic and diluted loss per share [Abstract]
Net loss	$ (4,485)	$ (4,956)	$ (4,130)	$ (5,608)	$ (6,417)	$ (4,934)	$ (6,450)	$ (7,605)	$ (19,180)	$ (25,406)
Basic and diluted weighted average number of shares outstanding (in shares)									68,564,321	62,985,763
Basic and diluted loss per share (in dollars per share)	$ (0.07)	$ (0.07)	$ (0.06)	$ (0.08)	$ (0.09)	$ (0.08)	$ (0.10)	$ (0.13)	$ (0.28)	$ (0.40)

- Definition

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

+ References + Details

Common Stock (Details) $ / shares in Units, $ in Thousands	12 Months Ended
Common Stock (Details) $ / shares in Units, $ in Thousands	Dec. 31, 2019 USD ($) Vote $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Aug. 31, 2018 USD ($)	Jul. 30, 2018 USD ($)	Mar. 08, 2018 USD ($)	Aug. 31, 2015 USD ($)
Common Stock [Abstract]
Common stock, shares authorized (in shares) \| shares	100,000,000	100,000,000
Common stock, par value (in dollars per share) \| $ / shares	$ 0.0001	$ 0.0001
Common Stock [Member]
Common Stock [Abstract]
Common stock, voting rights	Each share of common stock has the right to one vote
Number of votes entitled to each share of common stock \| Vote	1
Common stock, shares authorized (in shares) \| shares	100,000,000
Common stock, par value (in dollars per share) \| $ / shares	$ 0.0001
Number of shares of common stock sold (in shares) \| shares	1,860,483	7,510,555
Universal Shelf Registration Statement [Member] \| Common Stock [Member] \| Maximum [Member]
Common Stock [Abstract]
Securities offered for sale, aggregate value \| $				$ 100,000		$ 100,000
ATM Agreement [Member] \| Common Stock [Member]
Common Stock [Abstract]
Aggregate value of common stock available for offer and sale \| $	$ 26,592
Number of shares of common stock sold (in shares) \| shares	1,860,483	7,510,555
Average sales price per common share (in dollars per share) \| $ / shares	$ 5.84	$ 3.71
Aggregate proceeds from sales of common stock \| $	$ 10,866	$ 27,837
Sales commissions, fees and other costs associated with issuance of common stock \| $	$ 326	$ 785
ATM Agreement [Member] \| Common Stock [Member] \| Maximum [Member]
Common Stock [Abstract]
Securities offered for sale, aggregate value \| $			$ 50,000		$ 50,000	$ 35,000
Warrants [Member]
Information about warrants outstanding [Abstract]
Number of warrants issued (in shares) \| shares	25,000
Exercise price per common share (in dollars per share) \| $ / shares	$ 7.0
Expiration date	Apr. 30, 2020

Employee Benefit Plan (Details) - USD ($) $ in Thousands	12 Months Ended
Employee Benefit Plan (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Employee Benefit Plan [Abstract]
Matching contribution to defined contribution plan	$ 101	$ 95

Income Taxes, Components of Benefit (Provision) for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Current [Abstract]
Federal	$ 0	$ 0
State	393	(3)
Foreign	0	0
Current income tax benefit (provision)	393	(3)
Deferred [Abstract]
Federal	0	0
State	0	0
Total income tax provision	$ 393	$ (3)

Income Taxes, Reconciliation of Federal Statutory Income Tax Rate to Effective Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Effective Tax Rate Reconciliation [Abstract]
United States federal statutory rate	21.00%	21.00%
State taxes, net of federal benefit	1.99%	(0.01%)
Valuation allowance	(21.96%)	(24.33%)
Accounting method change - ASC 606	0.00%	2.07%
R&D Credit	1.34%	1.53%
Other	(0.38%)	(0.27%)
Effective income tax rate	1.99%	(0.01%)

Income Taxes, Net Operating Losses (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Income Taxes [Abstract]
Pre-tax losses available for carry forward	$ 19,573	$ 25,403

Income Taxes, Components of Deferred Tax Assets (Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets [Abstract]
Reserves and accruals	$ 62	$ 45
Research and development credits and other credits	1,730	1,635
Net operating loss carry forward	27,907	25,733
Stock based compensation	8,402	8,857
Other	11	26
Total deferred tax assets	38,112	36,296
Valuation allowance	(38,112)	(36,296)
Deferred tax assets after valuation allowance	0	0
Total deferred tax liability	0	0
Net deferred tax assets (liabilities)	$ 0	$ 0

Income Taxes, Valuation Allowance, Operating Loss Carryforwards and Tax Credit Carry-forwards (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Taxes [Abstract]
Net change in valuation allowance	$ 1,816
Income Taxes [Abstract]
Net operating loss carryforwards	19,573	$ 25,403
Federal [Member]
Income Taxes [Abstract]
Net operating loss carryforwards	$ 131,055
Operating loss carryforwards, expiration dates	Dec. 31, 2028
Federal [Member] \| Research and Development [Member]
Tax credit carryforwards [Abstract]
Tax credit carryforwards	$ 1,730
Federal tax credit carryforward, expiration dates	Dec. 31, 2032
State [Member]
Income Taxes [Abstract]
Net operating loss carryforwards	$ 107,989
Operating loss carryforwards, expiration dates	Dec. 31, 2029

Income Taxes, Income Tax Uncertainties (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Taxes [Abstract]
Accrued interest and penalties	$ 0
Reconciliation of Provision for Uncertain Tax Position [Roll Forward]
Balance at the beginning of the year	316	$ 316
Additions based on tax positions related to the current year	0	0
Additions for tax positions of prior years	0	0
Settlements	0	0
Lapse of applicable statute of limitations	(316)	0
Balance at the end of the year	$ 0	$ 316

Fair Value Measurement, Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value by Investment Category (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value of Financial Assets [Abstract]
Adjusted Cost	$ 3,135	$ 7,611
Adjusted Cost	3,450	4,366
Unrealized Gains	3	0
Unrealized Losses	0	0
Fair Value	3,453	4,366
Adjusted Cost	5,526	9,414
Fair Value	$ 5,529	9,414
Minimum [Member]
Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value of Financial Assets [Abstract]
Maturities of available for sale securities	1 year
Maximum [Member]
Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value of Financial Assets [Abstract]
Maturities of available for sale securities	2 years
Cash [Member]
Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value of Financial Assets [Abstract]
Adjusted Cost	$ 2,076	5,048
Fair Value	2,076	5,048
Cash and Cash Equivalents	2,076	5,048
Mutual Funds [Member]
Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value of Financial Assets [Abstract]
Adjusted Cost	613	1,107
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	613	1,107
US Agency Securities [Member]
Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value of Financial Assets [Abstract]
Adjusted Cost	2,837	3,259
Unrealized Gains	3	0
Unrealized Losses	0	0
Fair Value	2,840	3,259
Recurring [Member]
Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value of Financial Assets [Abstract]
Fair Value	3,135	7,611
Cash and Cash Equivalents	3,135	7,611
Investments Available for Sale	2,394	1,803
Recurring [Member] \| Cash [Member]
Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value of Financial Assets [Abstract]
Fair Value	2,076	5,048
Cash and Cash Equivalents	2,076	5,048
Recurring [Member] \| Level 1 [Member]
Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value of Financial Assets [Abstract]
Fair Value	1,059	2,563
Cash and Cash Equivalents	1,059	2,563
Investments Available for Sale	2,394	1,803
Recurring [Member] \| Level 1 [Member] \| Mutual Funds [Member]
Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value of Financial Assets [Abstract]
Fair Value	613	1,107
Cash and Cash Equivalents	613	1,107
Investments Available for Sale	0	0
Recurring [Member] \| Level 1 [Member] \| US Agency Securities [Member]
Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value of Financial Assets [Abstract]
Fair Value	446	1,456
Cash and Cash Equivalents	446	1,456
Investments Available for Sale	$ 2,394	$ 1,803

Litigation (Details)	Mar. 13, 2020 USD ($)	Sep. 20, 2018 USD ($)	Aug. 31, 2018 USD ($)	Sep. 29, 2017 USD ($)	Sep. 30, 2016 USD ($) Patent	Nov. 06, 2012 USD ($) Patent
VirnetX Inc. v. Apple, Inc. (Case 6:12-CV-00855-LED) ("Apple II") [Member]
Litigation [Abstract]
Amount of damages awarded in patent infringement case		$ 595,900,000	$ 502,600,000
Royalty rate per device used in calculating infringement damages			$ 1.2
Additional amount granted in agreed bill of costs, attorney fees, and prejudgment interest		$ 93,300,000
Positive Outcome of Litigation [Member] \| VirnetX Inc. v. Cisco Systems, Inc. et al. (Case 6:10-CV-00417-LED) ("Apple I") [Member]
Litigation [Abstract]
Amount of damages awarded in patent infringement case				$ 439,700,000	$ 302,400,000
Number of patents allegedly infringed upon by Apple, Inc. \| Patent					4	4
Enhanced damages				41,300,000
Costs, fees and interest				96,000,000
Positive Outcome of Litigation [Member] \| VirnetX Inc. v. Cisco Systems, Inc. et al. (Case 6:10-CV-00417-LED) ("Apple I") [Member] \| Subsequent Event [Member]
Litigation [Abstract]
Amount of final judgment with interest received	$ 454,034,000
Positive Outcome of Litigation [Member] \| VirnetX Inc. v. Cisco Systems, Inc. et al. (Case 6:10-CV-00417-LED) ("Apple I") [Member] \| Minimum [Member]
Litigation [Abstract]
Amount of damages awarded in patent infringement case						$ 368,000,000
Royalty rate per device used in calculating infringement damages				1.20
Positive Outcome of Litigation [Member] \| VirnetX Inc. v. Cisco Systems, Inc. et al. (Case 6:10-CV-00417-LED) ("Apple I") [Member] \| Maximum [Member]
Litigation [Abstract]
Royalty rate per device used in calculating infringement damages				$ 1.80

Quarterly Financial Information (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information (unaudited) [Abstract]
Revenue	$ 35	$ 4	$ 38	$ 8	$ 34	$ 7	$ 16	$ 6	$ 85	$ 63
Loss from operations	(4,503)	(4,976)	(4,552)	(5,634)	(6,439)	(4,948)	(6,462)	(7,608)	(19,665)	(25,457)
Net Loss	$ (4,485)	$ (4,956)	$ (4,130)	$ (5,608)	$ (6,417)	$ (4,934)	$ (6,450)	$ (7,605)	$ (19,180)	$ (25,406)
Basic and diluted (loss) per common share (in dollars per share)	$ (0.07)	$ (0.07)	$ (0.06)	$ (0.08)	$ (0.09)	$ (0.08)	$ (0.10)	$ (0.13)	$ (0.28)	$ (0.40)

- Definition

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

+ References + Details

Effects of Adopting ASU Topic 842 - Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Effects of Adopting ASU Topic 842 - Leases [Abstract]
Prepaid lease payments for promotional and marketing facility		$ 4,000
ASU Topic 842 [Member]
Effects of Adopting ASU Topic 842 - Leases [Abstract]
Operating lease ROU assets	$ 97	$ 45
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PrepaidExpenseAndOtherAssetsNoncurrent	us-gaap:PrepaidExpenseAndOtherAssetsNoncurrent
Lease liability	$ 97	$ 45
Offices [Member]
Effects of Adopting ASU Topic 842 - Leases [Abstract]
Operating lease, expiration date	Oct. 31, 2021
Facility Used for Corporate Promotional and Marketing Purposes [Member]
Effects of Adopting ASU Topic 842 - Leases [Abstract]
Operating lease, expiration date	Dec. 31, 2024
Current Assets [Member]
Effects of Adopting ASU Topic 842 - Leases [Abstract]
Prepaid lease payments for promotional and marketing facility		385
Noncurrent Assets [Member] \| ASU Topic 842 [Member]
Effects of Adopting ASU Topic 842 - Leases [Abstract]
Prepaid lease payments for promotional and marketing facility		$ 385

Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Thousands		2 Months Ended		12 Months Ended
	Mar. 13, 2020	Mar. 10, 2020	Feb. 21, 2020	Dec. 31, 2019	Dec. 31, 2018
Common Stock [Member]
Stock Transactions [Abstract]
Number of shares of common stock sold (in shares)				1,860,483	7,510,555
ATM Agreement [Member] \| Common Stock [Member]
Stock Transactions [Abstract]
Number of shares of common stock sold (in shares)				1,860,483	7,510,555
Average sales price per common share (in dollars per share)				$ 5.84	$ 3.71
Aggregate proceeds from sales of common stock				$ 10,866	$ 27,837
Sales commissions, fees and other costs associated with issuance of common stock				$ 326	$ 785
Subsequent Event [Member]
Stock Transactions [Abstract]
Options exercised (in shares)		151,308
Subsequent Event [Member] \| Positive Outcome of Litigation [Member] \| VirnetX Inc. v. Cisco Systems, Inc. et al. (Case 6:10-CV-00417-LED) ("Apple I") [Member]
Stock Transactions [Abstract]
Amount of final judgment with interest received	$ 454,034
Subsequent Event [Member] \| ATM Agreement [Member] \| Common Stock [Member]
Stock Transactions [Abstract]
Number of shares of common stock sold (in shares)			1,049,382
Average sales price per common share (in dollars per share)			$ 4.41
Aggregate proceeds from sales of common stock			$ 4,627
Sales commissions, fees and other costs associated with issuance of common stock			$ 139