Inovio Pharmaceuticals (INO) 10-Q 9 Aug 21 2021 Q2 Quarterly report Financial data

Cover Page

Cover Page - shares	6 Months Ended
	Jun. 30, 2021	Aug. 06, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2021
Document Transition Report	false
Entity File Number	001-14888
Entity Registrant Name	INOVIO PHARMACEUTICALS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	33-0969592
Entity Address, Address Line One	660 W. GERMANTOWN PIKE, SUITE 110
Entity Address, City or Town	PLYMOUTH MEETING
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	19462
City Area Code	267
Local Phone Number	440-4200
Title of 12(b) Security	COMMON STOCK, $0.001 PAR VALUE
Trading Symbol	INO
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		210,356,896
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Entity Central Index Key	0001055726
Current Fiscal Year End Date	--12-31

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($)	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 58,925,302	$ 250,728,118
Short-term investments	384,752,382	160,914,935
Accounts receivable	13,128,330	18,559,967
Accounts receivable from affiliated entities	722,941	503,782
Prepaid expenses and other current assets	84,592,179	40,357,456
Prepaid expenses and other current assets from affiliated entities	303,491	106,432
Total current assets	542,424,625	471,170,690
Fixed assets, net	18,111,288	11,348,144
Investment in affiliated entity	3,908,709	4,460,366
Investment in Geneos	0	434,387
Intangible assets, net	2,879,896	3,146,770
Goodwill	10,513,371	10,513,371
Operating lease right-of-use assets	12,173,414	12,741,296
Other assets	1,830,866	25,957,448
Total assets	591,842,169	539,772,472
Current liabilities:
Accounts payable and accrued expenses	30,095,578	21,203,808
Accounts payable and accrued expenses due to affiliated entities	1,773,846	642,969
Accrued clinical trial expenses	10,416,164	9,950,345
Deferred revenue	109,128	46,628
Operating lease liability	2,463,878	2,329,394
Grant funding liability	6,859,155	7,474,310
Grant funding liability from affiliated entities	31,250	58,500
Total current liabilities	51,748,999	41,705,954
Deferred revenue, net of current portion	71,788	79,214
Operating lease liability, net of current portion	16,797,476	18,063,515
Deferred tax liabilities	32,046	32,046
Grant funding liability from affiliated entity, net of current portion	37,500	37,500
Other liabilities	64,141	57,663
Total liabilities	83,288,398	78,631,714
Stockholders’ equity:
Preferred stock	0	0
Common stock	210,146	186,851
Additional paid-in capital	1,551,348,435	1,367,406,869
Accumulated deficit	(1,042,738,901)	(906,196,812)
Accumulated other comprehensive loss	(265,909)	(256,150)
Total Inovio Pharmaceuticals, Inc. stockholders’ equity	508,553,771	461,140,758
Total liabilities and stockholders’ equity	591,842,169	539,772,472
Convertible senior notes
Current liabilities:
Convertible debt	14,536,448	14,139,988
Convertible bonds
Current liabilities:
Convertible debt	$ 0	$ 4,515,834

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenues:
Total revenues	$ 272,824	$ 267,187	$ 643,945	$ 1,594,461
Operating expenses:
Research and development	70,808,418	22,376,575	109,852,836	41,487,763
General and administrative	12,666,341	11,071,510	26,547,535	18,519,864
Total operating expenses	83,474,759	33,448,085	136,400,371	60,007,627
Loss from operations	(83,201,935)	(33,180,898)	(135,756,426)	(58,413,166)
Other income (expense):
Interest income	928,111	1,067,399	1,697,347	1,483,968
Interest expense	(466,726)	(2,846,641)	(979,760)	(5,650,396)
Change in fair value of derivative liability	0	(97,755,000)	0	(110,976,977)
Gain (loss) on investment in affiliated entities	278,818	(3,883,176)	(551,657)	9,298,443
Net unrealized gain (loss) on available-for-sale equity securities	136,493	4,358,634	(711,465)	(691,458)
Other income (expense), net	185,281	(152,102)	194,259	(577,602)
Gain on deconsolidation of Geneos	0	4,121,075	0	4,121,075
Net loss before share in net loss of Geneos	(82,139,958)	(128,270,709)	(136,107,702)	(161,406,113)
Share in net loss of Geneos	0	(901,757)	(434,387)	(901,757)
Net loss	(82,139,958)	(129,172,466)	(136,542,089)	(162,307,870)
Net loss attributable to non-controlling interest	0	469,407	0	1,063,757
Net loss attributable to Inovio Pharmaceuticals, Inc.	$ (82,139,958)	$ (128,703,059)	$ (136,542,089)	$ (161,244,113)
Net loss per share attributable to Inovio Pharmaceuticals, Inc. stockholders
Basic (in dollars per share)	$ (0.39)	$ (0.83)	$ (0.66)	$ (1.15)
Diluted (in dollars per share)	$ (0.39)	$ (0.83)	$ (0.66)	$ (1.15)
Weighted average number of common shares outstanding
Basic (in shares)	209,561,064	155,807,054	206,007,497	140,215,158
Diluted (in shares)	209,561,064	155,807,054	206,007,497	140,215,158
Revenue under collaborative research and development arrangements
Revenues:
Total revenues	$ 82,923	$ 74,102	$ 122,538	$ 145,602
Revenue under collaborative research and development arrangements with affiliated entities
Revenues:
Total revenues	74,787	95,146	124,736	1,267,272
Other revenue
Revenues:
Total revenues	$ 115,114	$ 97,939	$ 396,671	$ 181,587

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Loss - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement of Comprehensive Income [Abstract]
Net loss	$ (82,139,958)	$ (129,172,466)	$ (136,542,089)	$ (162,307,870)
Other comprehensive income (loss):
Foreign currency translation	2,478	0	(11,941)	0
Unrealized gain (loss) on short-term investments, net of tax	(2,679)	846,900	2,182	(1,082,638)
Comprehensive loss	(82,140,159)	(128,325,566)	(136,551,848)	(163,390,508)
Comprehensive loss attributable to non-controlling interest	0	469,407	0	1,063,757
Comprehensive loss attributable to Inovio Pharmaceuticals, Inc.	$ (82,140,159)	$ (127,856,159)	$ (136,551,848)	$ (162,326,751)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity - USD ($)	Total	Preferred stock	Common stock	Additional paid-in capital	Accumulated deficit	Accumulated other comprehensive income (loss)	Non- controlling interest
Beginning balance (in shares) at Dec. 31, 2019		23	101,361,034
Beginning balance at Dec. 31, 2019	$ 5,404,858	$ 0	$ 101,361	$ 742,646,785	$ (739,785,655)	$ 472,608	$ 1,969,759
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock for cash, net of financing costs (in shares)			43,148,952
Issuance of common stock for cash, net of financing costs	208,241,933		$ 43,149	208,198,784
Exercise of stock options for cash and vesting of RSUs, net of tax payments (in shares)			1,405,114
Exercise of stock options for cash and vesting of RSUs, net of tax payments	3,100,703		$ 1,405	3,099,298
Stock-based compensation	4,001,553			4,017,761			(16,208)
Acquisition of non-controlling interest in Geneos	2,169,998						2,169,998
Net loss attributable to common stockholders	(33,135,404)				(32,541,054)		(594,350)
Unrealized gain (loss) on short-term investments, net of tax	(1,929,538)					(1,929,538)
Ending balance (in shares) at Mar. 31, 2020		23	145,915,100
Ending balance at Mar. 31, 2020	187,854,103	$ 0	$ 145,915	957,962,628	(772,326,709)	(1,456,930)	3,529,199
Beginning balance (in shares) at Dec. 31, 2019		23	101,361,034
Beginning balance at Dec. 31, 2019	5,404,858	$ 0	$ 101,361	742,646,785	(739,785,655)	472,608	1,969,759
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss attributable to common stockholders	(162,307,870)
Unrealized gain (loss) on short-term investments, net of tax	(1,082,638)
Foreign currency translation	0
Ending balance (in shares) at Jun. 30, 2020		9	158,756,411
Ending balance at Jun. 30, 2020	186,360,469	$ 0	$ 158,756	1,087,745,242	(901,029,768)	(610,030)	96,269
Beginning balance (in shares) at Mar. 31, 2020		23	145,915,100
Beginning balance at Mar. 31, 2020	187,854,103	$ 0	$ 145,915	957,962,628	(772,326,709)	(1,456,930)	3,529,199
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock for cash, net of financing costs (in shares)			12,041,178
Issuance of common stock for cash, net of financing costs	121,718,922		$ 12,041	121,706,881
Conversion of preferred stock to common stock (in shares)		14	5,147
Conversion of preferred stock to common stock	0		$ 5	(5)
Exercise of stock options for cash and vesting of RSUs, net of tax payments (in shares)			794,986
Exercise of stock options for cash and vesting of RSUs, net of tax payments	4,422,244		$ 795	4,421,449
Stock-based compensation	3,662,435			3,654,289			8,146
Acquisition of non-controlling interest in Geneos	209,971						209,971
Deconsolidation of Geneos	(3,181,640)						(3,181,640)
Net loss attributable to common stockholders	(129,172,466)				(128,703,059)		(469,407)
Unrealized gain (loss) on short-term investments, net of tax	846,900					846,900
Foreign currency translation	0
Ending balance (in shares) at Jun. 30, 2020		9	158,756,411
Ending balance at Jun. 30, 2020	186,360,469	$ 0	$ 158,756	1,087,745,242	(901,029,768)	(610,030)	$ 96,269
Beginning balance (in shares) at Dec. 31, 2020		9	186,851,493
Beginning balance at Dec. 31, 2020	461,140,758	$ 0	$ 186,851	1,367,406,869	(906,196,812)	(256,150)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock for cash, net of financing costs (in shares)			20,355,000
Issuance of common stock for cash, net of financing costs	162,105,030		$ 20,355	162,084,675
Conversion of preferred stock to common stock (in shares)			1,009,450
Conversion of preferred stock to common stock	4,377,892		$ 1,009	4,376,883
Exercise of stock options for cash and vesting of RSUs, net of tax payments (in shares)			1,118,093
Exercise of stock options for cash and vesting of RSUs, net of tax payments	(1,201,789)		$ 1,118	(1,202,907)
Stock-based compensation	9,595,947			9,595,947
Net loss attributable to common stockholders	(54,402,131)				(54,402,131)
Unrealized gain (loss) on short-term investments, net of tax	4,861					4,861
Foreign currency translation	(14,419)					(14,419)
Ending balance (in shares) at Mar. 31, 2021		9	209,334,036
Ending balance at Mar. 31, 2021	581,606,149	$ 0	$ 209,333	1,542,261,467	(960,598,943)	(265,708)
Beginning balance (in shares) at Dec. 31, 2020		9	186,851,493
Beginning balance at Dec. 31, 2020	461,140,758	$ 0	$ 186,851	1,367,406,869	(906,196,812)	(256,150)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss attributable to common stockholders	(136,542,089)
Unrealized gain (loss) on short-term investments, net of tax	2,182
Foreign currency translation	(11,941)
Ending balance (in shares) at Jun. 30, 2021		9	210,146,880
Ending balance at Jun. 30, 2021	508,553,771	$ 0	$ 210,146	1,551,348,435	(1,042,738,901)	(265,909)
Beginning balance (in shares) at Mar. 31, 2021		9	209,334,036
Beginning balance at Mar. 31, 2021	581,606,149	$ 0	$ 209,333	1,542,261,467	(960,598,943)	(265,708)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options for cash and vesting of RSUs, net of tax payments (in shares)			812,844
Exercise of stock options for cash and vesting of RSUs, net of tax payments	3,441,423		$ 813	3,440,610
Stock-based compensation	5,646,358			5,646,358
Net loss attributable to common stockholders	(82,139,958)				(82,139,958)
Unrealized gain (loss) on short-term investments, net of tax	(2,679)					(2,679)
Foreign currency translation	2,478					2,478
Ending balance (in shares) at Jun. 30, 2021		9	210,146,880
Ending balance at Jun. 30, 2021	$ 508,553,771	$ 0	$ 210,146	$ 1,551,348,435	$ (1,042,738,901)	$ (265,909)

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Stockholders' Equity (Parenthetical) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)
Statement of Stockholders' Equity [Abstract]
Stock issuance costs	$ 531

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows - USD ($)	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities:
Net loss	$ (136,542,089)	$ (162,307,870)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	1,361,595	1,608,060
Amortization of intangible assets	266,874	273,540
Change in fair value of derivative liability	0	110,976,977
Stock-based compensation	15,242,305	7,663,988
Non-cash interest expense	435,445	3,013,942
(Gain) loss on short-term investments	(153,252)	576,001
Settlement of receivable with shares of common stock from affiliated entity (PLS)	0	(1,713,770)
Gain on deconsolidation of Geneos	0	4,121,075
Gain (loss) on equity investment in affiliated entities	551,657	(9,298,443)
Share of net loss in Geneos	434,387	901,757
Net unrealized loss on available-for-sale equity securities	711,465	691,458
Non-cash lease expense	567,882	517,865
Unrealized transaction gain on foreign-currency denominated debt	(176,927)	(474,071)
Changes in operating assets and liabilities:
Accounts receivable	5,431,637	(2,813,086)
Accounts receivable from affiliated entities	(219,159)	865,832
Prepaid expenses and other current assets	(51,944,060)	(3,084,082)
Prepaid expenses and other current assets from affiliated entities	(197,059)	(1,330,601)
Other assets	24,126,582	116,242
Accounts payable and accrued expenses	8,891,770	(732,774)
Accrued clinical trial expenses	465,819	2,882,486
Accounts payable and accrued expenses due to affiliated entities	1,130,877	4,634
Deferred revenue	55,074	(92,426)
Deferred revenue from affiliated entities	(6,250)	62,500
Operating lease right-of-use assets and liabilities, net	(1,131,555)	(1,022,951)
Grant funding liability	(615,155)	4,265,023
Grant funding liability from affiliated entities	(21,000)	(63,050)
Other liabilities	6,478	29,686
Net cash used in operating activities	(131,326,659)	(52,604,208)
Cash flows from investing activities:
Purchases of investments	(307,857,113)	(138,698,249)
Proceeds from sale or maturity of investments	83,466,967	47,455,067
Purchases of capital assets	(418,734)	(176,534)
Decrease in cash resulting from the deconsolidation of Geneos	0	2,774,851
Net cash used in investing activities	(224,808,880)	(94,194,567)
Cash flows from financing activities:
Proceeds from issuance of common stock, net of issuance costs	162,105,030	329,960,855
Proceeds from stock option exercises	6,154,794	9,599,514
Taxes paid related to net share settlement of equity awards	(3,915,160)	(2,076,567)
Acquisition of non-controlling interest	0	2,379,969
Proceeds from Geneos issuance of note payable	0	171,620
Net cash provided by financing activities	164,344,664	340,035,391
Effect of exchange rate changes on cash and cash equivalents	(11,941)	0
(Decrease) Increase in cash and cash equivalents	(191,802,816)	193,236,616
Cash and cash equivalents, beginning of period	250,728,118	22,196,097
Cash and cash equivalents, end of period	58,925,302	215,432,713
Supplemental disclosures:
Amounts accrued for purchases of property and equipment	0	1,620
Interest paid	$ 544,315	$ 2,636,454

Organization and Operations

Organization and Operations	6 Months Ended
	Jun. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Operations	Organization and Operations Inovio Pharmaceuticals, Inc. (the “Company” or “INOVIO”), is a biotechnology company focused on rapidly bringing to market precisely designed DNA medicines to treat and protect people from infectious diseases, cancer, and diseases associated with human papillomavirus ("HPV"). INOVIO's DNA medicines pipeline is comprised of three types of product candidates: DNA vaccines, DNA immunotherapies and DNA encoded monoclonal antibodies ("dMAbs"). In clinical trials, INOVIO has demonstrated that DNA medicines can be delivered directly into cells in the body through its proprietary smart device to consistently activate robust and fully functional T cell and antibody responses against targeted pathogens and cancers. The Company's novel DNA medicine candidates are made using its proprietary SynCon ® technology that creates optimized plasmids, which are circular strands of DNA that instruct a cell to produce antigens to help the person’s immune system recognize and destroy cancerous or virally infected cells. INOVIO's patented CELLECTRA ® smart delivery devices provide optimized uptake of its DNA medicines within the cell, overcoming a key limitation of other DNA-based technology approaches. Human clinical trial data to date have shown a favorable safety profile of INOVIO's DNA medicines delivered directly into cells in the body using the CELLECTRA ® smart device in more than 7,000 administrations across more than 3,000 patients. INOVIO's corporate strategy is to advance, protect and, once approved, commercialize its novel DNA medicines to meet urgent and emerging global health needs. The Company continues to advance and clinically validate an array of DNA medicine candidates that target HPV-associated diseases, cancer, and infectious diseases, such as COVID-19. The Company aims to advance these candidates through commercialization and continue to leverage third-party resources through collaborations and partnerships, including product license agreements. The Company's partners and collaborators include ApolloBio Corporation., AstraZeneca, Beijing Advaccine, The Bill & Melinda Gates Foundation, Coalition for Epidemic Preparedness Innovations ("CEPI"), The U.S. Department of Defense ("DoD"), Defense Advanced Research Projects Agency ("DARPA"), GeneOne Life Science, HIV Vaccines Trial Network, the U.S. Defense Threat Reduction Agency’s Medical CBRN Defense Consortium ("MCDC"), International Vaccine Institute ("IVI"), National Cancer Institute, National Institutes of Health, National Institute of Allergy and Infectious Diseases, Ology Bioservices, the Parker Institute for Cancer Immunotherapy, Plumbline Life Sciences, Regeneron Pharmaceuticals, Inc., Richter-Helm BioLogics, Thermo Fisher Scientific, the University of Pennsylvania, the Walter Reed Army Institute of Research, and The Wistar Institute. The Company and its collaborators are currently conducting or planning clinical studies of its DNA medicines for COVID-19; Middle East Respiratory Syndrome, or MERS; Lassa fever; HIV; Ebola; as well as HPV-associated precancers, including cervical, vulvar, and anal dysplasia; HPV-associated cancers, including head & neck, cervical, anal, penile, vulvar, and vaginal; other HPV-associated disorders, such as recurrent respiratory papillomatosis, or RRP; glioblastoma multiforme, or GBM; and prostate cancer. INOVIO was incorporated in Delaware in June 2001 and has its principal executive offices in Plymouth Meeting, Pennsylvania.

Basis of Presentation, Liquidit

Basis of Presentation, Liquidity and Risks and Uncertainties	6 Months Ended
	Jun. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation, Liquidity and Risks and Uncertainties	Basis of Presentation, Liquidity and Risks and Uncertainties Basis of Presentation The accompanying unaudited condensed consolidated financial statements of Inovio have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) as contained in the Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC") for interim financial information and with instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. The condensed consolidated balance sheet as of June 30, 2021, the condensed consolidated statements of operations, the condensed consolidated statements of comprehensive loss and the condensed consolidated statements of stockholders' equity for the three and six months ended June 30, 2021 and 2020 and the condensed consolidated statements of cash flows for the six months ended June 30, 2021 and 2020 are unaudited, but include all adjustments (consisting of normal recurring adjustments) that the Company considers necessary for a fair presentation of the financial position, results of operations, cash flows and changes in stockholders' equity for the periods presented. The results of operations for the three and six months ended June 30, 2021 shown herein are not necessarily indicative of the results that may be expected for the year ending December 31, 2021, or for any other period. These unaudited financial statements, and notes thereto, should be read in conjunction with the audited consolidated financial statements for the year ended December 31, 2020, included in the Company's Annual Report on Form 10-K filed with the U.S. Securities and Exchange Commission (“SEC”) on March 1, 2021. The balance sheet at December 31, 2020 has been derived from the audited financial statements at that date, but does not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In June 2020, the Company formed a wholly-owned subsidiary, Inovio Asia LLC, under the laws of South Korea, through which the Company intends to advance its corporate development projects and other functions in South Korea and other Asian countries. These unaudited condensed consolidated financial statements include the accounts of Inovio Pharmaceuticals, Inc. and its subsidiarie s. As of June 30, 2021, the Company consolidated its wholly-owned subsidiary Inovio Asia LLC. On December 31, 2020, former wholly-owned subsidiaries Genetronics, Inc. and VGX Pharmaceuticals Inc. and former majority-owned subsidiary VGX Animal Health, Inc. were merged into Inovio Pharmaceuticals, Inc. All intercompany accounts and transactions were eliminated upon consolidation. As of June 1, 2020, the Company deconsolidated its former subsidiary Geneos Therapeutics, Inc. ("Geneos"), as the Company no longer held a controlling financial interest. Refer to Footnote 17 for further discussion. Liquidity The Company incurred a net loss attributable to common stockholders of $82.1 million and $136.5 million for the three and six months ended June 30, 2021, respectively. The Company had working capital of $490.7 million and an accumulated deficit of $1.0 billion as of June 30, 2021. The Company has incurred losses in each year since its inception and expects to continue to incur significant expenses and operating losses for the foreseeable future in connection with the research and preclinical and clinical development of its product candidates. The Company’s cash, cash equivalents and short-term investments of $443.7 million as of June 30, 2021 are sufficient to support the Company's operations for a period of at least 12 months from the date of issuance of these financial statements. In order to continue to fund future research and development activit ies, the Company will need to seek additional capital. This may occur through strategic alliance and licensing arrangements, grant agreements and/or future public or private debt or equity financings including use of potential future At-the-Market Equity Offering Sales Agreements (“Sales Agreements”). The Company has a history of conducting debt and equity financings, including the receipt of net proceeds of $162.1 million from a January 2021 underwritten public offering and net proceeds of $454.5 million under past Sales Agreements for the year ended December 31, 2020. However, sufficient funding may not be available in the future, or if available, may be on terms that significantly dilute or otherwise adversely affect the rights of existing stockholders. If adequate funds are not available, the Company may need to delay, reduce the scope of or put on hold one or more of its clinical and/or preclinical programs. The Company’s ability to continue its operations is dependent upon its ability to obtain additional capital in the future and achieve profitable operations. The Company expects to continue to rely on outside sources of financing to meet its capital needs and the Company may never achieve positive cash flow. These condensed consolidated financial statements do not include any adjustments to the specific amounts and classifications of assets and liabilities, which might be necessary should Inovio be unable to continue as a going concern. The Company's condensed consolidated financial statements as of and for the three and six months ended June 30, 2021 have been prepared on a going concern basis, which contemplates the realization of assets and the settlement of liabilities and commitments in the normal course of business for the foreseeable future. The Company has evaluated subsequent events after the balance sheet date through the date it issued these condensed consolidated financial statements. The Company is and, from time to time, may in the future be subject to various legal proceedings and claims arising in the ordinary course of business. The Company assesses contingencies to determine the degree of probability and range of possible loss for potential accrual in its consolidated financial statements. An estimated loss contingency is accrued in the consolidated financial statements if it is probable that a liability has been incurred and the amount of the loss can be reasonably estimated. Legal proceedings, including litigation, government investigations and enforcement actions, could result in material costs, occupy significant management resources and entail civil and criminal penalties, even if the Company ultimately prevails. Any of the foregoing consequences could result in serious harm to the Company’s business, results of operations and financial condition. Risks and Uncertainties The global pandemic resulting from COVID-19, caused by a novel strain of coronavirus, SARS-CoV-2, has caused national and global economic and financial market disruptions. The impact of this pandemic has been and will likely continue to be extensive in many aspects of society, which has resulted in and will continue to cause significant disruptions to the global economy, as well as businesses and capital markets around the world. The Company continues to closely monitor the impact of the COVID-19 pandemic on its employees, collaborators and service providers. The extent to which the pandemic will continue to impact the Company's business and operations will depend on future developments, including travel restrictions and social distancing in the United States and other countries, and the

Critical Accounting Policies

Critical Accounting Policies	6 Months Ended
	Jun. 30, 2021
Accounting Policies [Abstract]
Critical Accounting Policies	Critical Accounting Policies Collaboration Agreements The Company assesses whether its collaboration agreements are subject to ASC Topic 808: Collaborative Arrangements (“Topic 808”) based on whether they involve joint operating activities and whether both parties have active participation in the arrangement and are exposed to significant risks and rewards. To the extent that the arrangement falls within the scope of Topic 808 and the Company concludes that its collaboration partner is not a customer, the Company presents such payments as a reduction of research and development expense. If payments from the collaboration partner to the Company represent consideration from a customer, then the Company accounts for those payments within the scope of Accounting Standards Update (“ASU”) 2014-09, Revenue from Contracts with Customers (“Topic 606”). Revenue Recognition The Company recognizes revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which it expects to be entitled in exchange for those goods or services. To determine revenue recognition for contracts with customers, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the Company satisfies its performance obligations. At contract inception, the Company assesses the goods or services agreed upon within each contract and assess whether each good or service is distinct and determine those that are performance obligations. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. Collaborative Arrangements The Company enters into collaborative arrangements with partners that typically include payment of one or more of the following: (i) license fees; (ii) product supply services; (iii) milestone payments related to the achievement of developmental, regulatory, or commercial goals; and (iv) royalties on net sales of licensed products. Where a portion of non-refundable, upfront fees or other payments received are allocated to continuing performance obligations under the terms of a collaborative arrangement, they are recorded as deferred revenue and recognized as revenue when (or as) the underlying performance obligation is satisfied. As part of the accounting for these arrangements, the Company must develop estimates and assumptions that require judgment of management to determine the underlying stand-alone selling price for each performance obligation which determines how the transaction price is allocated among the performance obligation. The standalone selling price may include items such as forecasted revenues, development timelines, discount rates and probabilities of technical and regulatory success. The Company evaluates each performance obligation to determine if it can be satisfied at a point in time or over time. In addition, variable consideration must be evaluated to determine if it is constrained and, therefore, excluded from the transaction price. License Fees If a license to intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company will recognize revenues from non-refundable, upfront fees allocated to the license when the license is transferred to the licensee and the licensee is able to use and benefit from the license. For licenses that are bundled with other promises, the Company will utilize judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. Product Supply Services Arrangements that include a promise for future supply of drug product for either clinical development or commercial supply at the licensee’s discretion are generally considered as options. The Company will assess if these options provide a material right to the licensee and if so, they will be accounted for as separate performance obligations. The Company evaluates whether it is the principal or agent in the arrangement. The Company had determined that it is the principal in the current arrangements as the Company controls the product supply before it is transferred to the customer. Milestone Payments At the inception of each arrangement that includes milestone payments (variable consideration), the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company's or its collaboration partner’s control, such as regulatory approvals, are generally not considered probable of being achieved until those approvals are received. The transaction price is then allocated to each performance obligation on a relative stand-alone selling price basis, for which the Company recognizes revenue as or when the performance obligations under the contract are satisfied. At the end of each subsequent reporting period, the Company re-evaluates the probability of achieving such milestones and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect license, collaboration or other revenues and earnings in the period of adjustment. Royalties For arrangements that include sales-based royalties, including milestone payments based on the level of sales, and for which the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date, the Company has not recognized any royalty revenue resulting from any of its collaborative arrangements. Grants The Company accounts for various grant agreements under the contributions guidance under Subtopic 958-605, Not-for-Profit Entities-Revenue Recognition , which is outside the scope of Topic 606, as the government agencies granting the Company funds are not receiving reciprocal value for their contributions. All contributions received from current grant agreements are recorded as a contra-expense as opposed to revenue on the condensed consolidated statement of operations. Leases For its long-term operating leases, the Company recognizes an operating lease right-of-use asset and an operating lease liability on its condensed consolidated balance sheets. The lease liability is determined as the present value of future lease payments using an estimated rate of interest that the Company would pay to borrow equivalent funds on a collateralized basis at the lease commencement date. The right-of-use asset is based on the liability adjusted for any prepaid or deferred rent. The Company determines the lease term at the commencement date by considering whether renewal options and termination options are reasonably assured of exercise. Fixed rent expense for the Company's operating leases is recognized on a straight-line basis over the term of the lease and is included in operating expenses on the condensed consolidated statements of operations. Variable lease payments including lease operating expenses are recorded as incurred. Research and Development Expenses The Company’s activities have largely consisted of research and development efforts related to developing electroporation delivery technologies, DNA vaccines, DNA immunotherapies and dMABs. Research and development expenses consist of expenses incurred in performing research and development activities including salaries and benefits, facilities and other overhead expenses, clinical trials, contract services and other outside expenses. Research and development expenses are charged to operations as they are incurred. These expenses result from the Company's independent research and development efforts as well as efforts associated with collaborations and licensing arrangements. The Company reviews and accrues clinical trial expense based on work performed, which relies on estimates of total costs incurred based on patient enrollment, completion of studies and other events. Accrued clinical trial costs are subject to revisions as trials progress. Revisions are charged to expense in the period in which the facts that give rise to the revision become known. Historically, revisions have not resulted in material changes to research and development expense; however, a modification in the protocol of a clinical trial or cancellation of a trial could result in a charge to the Company's results of operations. Advance payments for goods or services to be rendered in the future for use in research and development activities are deferred and included in prepaid expenses and other assets. The deferred amounts are expensed as the related goods are delivered or the services are performed. Valuation of Intangible Assets and Goodwill Intangible assets are amortized over their estimated useful lives ranging from two License costs are recorded based on the fair value of consideration paid and are amortized using the straight-line method over the shorter of the expected useful life of the underlying patents or the term of the related license agreement to the extent the license has an alternative future use. As of June 30, 2021 and December 31, 2020, the Company’s intangible assets resulting from the acquisition of Inovio AS and Bioject Medical Technologies, Inc. ("Bioject"), and additional intangibles including license costs, net of accumulated amortization, totaled $2.9 million and $3.1 million, respectively. The determination of the value of intangible assets requires management to make estimates and assumptions that affect the Company’s condensed consolidated financial statements. The Company assesses potential impairments to intangible assets when there is evidence that events or changes in circumstances indicate that the carrying amount of an asset may not be recovered. The Company’s judgments regarding the existence of impairment indicators and future cash flows related to intangible assets are based on operational performance of its acquired businesses, market conditions and other factors. If impairment is indicated, the Company will reduce the carrying value of the intangible asset to fair value. While current and historical operating and cash flow losses are potential indicators of impairment, the Company believes the future cash flows to be received from its intangible assets will exceed the intangible assets’ carrying value, and accordingly, the Company has not recognized any impairment losses through June 30, 2021. Goodwill represents the excess of acquisition cost over the fair value of the net assets of acquired businesses. Goodwill is reviewed for impairment at least annually at November 30, or more frequently if an event occurs indicating the potential for impairment. During its goodwill impairment review, the Company may assess qualitative factors to determine whether it is more likely than not that the fair value of its reporting unit is less than its carrying amount, including goodwill. The qualitative factors include, but are not limited to, macroeconomic conditions, industry and market considerations, and the overall financial performance of the Company. If, after assessing the totality of these qualitative factors, the Company determines that it is not likely that the fair value of its reporting unit is less than its carrying amount, then no additional assessment is deemed necessary. Otherwise, the Company will proceed to perform the impairment test in which the fair value of the reporting unit is compared with its carrying amount, and an impairment charge will be recorded for the amount by which the carrying amount exceeds the reporting unit's fair value, if any. The Company performed its annual assessment for goodwill impairment as of November 30, 2020, identifying no impairment. Although there are inherent uncertainties in this assessment process, the estimates and assumptions the Company is using are consistent with its internal planning. If these estimates or their related assumptions change in the future, the Company may be required to record an impairment charge on all or a portion of its goodwill and intangible assets. Furthermore, the Company cannot predict the occurrence of future impairment triggering events nor the impact such events might have on its reported asset values. Future events could cause the Company to conclude that impairment indicators exist and that goodwill or other intangible assets associated with its acquired businesses are impaired. Any resulting impairment loss could have an adverse impact on the Company’s results of operations. See Note 8 for further discussion of the Company’s goodwill and intangible assets. Foreign Currency Translation The functional and presentation currency of the Company is the U.S. dollar. Transactions denominated in a currency other than the functional currency are recorded on the initial recognition at the exchange rate at the date of the transaction. After initial recognition monetary assets and liabilities denominated in foreign currency are translated at the end of each reporting period into the functional currency at the exchange rate at that date. The cumulative translation adjustment is included in the accumulated other comprehensive income (loss) within the statement of stockholders' equity. Exchange differences are included in general and administrative expenses in the condensed consolidated statement of operations. Non- monetary assets and liabilities measured at cost are translated at the exchange rate at the date of the transaction. Variable Interest Entities (VIE) The Company evaluates its ownership, contractual and other interests in entities that are not wholly-owned to determine if these entities are VIEs, and, if so, whether the Company is the primary beneficiary of the VIE. In determining whether the Company is the primary beneficiary of a VIE and therefore required to consolidate the VIE, the Company applies a qualitative approach that determines whether it has both (1) the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance and (2) the obligation to absorb losses of, or the rights to receive benefits from, the VIE that could potentially be significant to that VIE. The Company will continuously perform this assessment, as changes to existing relationships or future transactions may result in the consolidation or deconsolidation of a VIE. Equity Investments Under ASC Topic 321, Investments - Equity Securities, the Company must measure equity investments (except those accounted for under the equity method, those that result in consolidation of the investee and certain other investments) at fair value and recognize any changes in fair value in the condensed consolidated statement of operations. The Company can elect a measurement alternative for equity investments that do not have readily determinable fair values and do not qualify for the practical expedient in ASC 820, Fair Value Measurement, to estimate fair value using the net asset value per share (or its

Impact of Recently Issued Accou

Impact of Recently Issued Accounting Standards	6 Months Ended
	Jun. 30, 2021
Accounting Policies [Abstract]
Impact of Recently Issued Accounting Standards	Impact of Recently Issued Accounting Standards The recent accounting pronouncements below may have a significant effect on the Company's financial statements. Recent accounting pronouncements that are not anticipated to have an impact on or are unrelated to the Company's financial condition, results of operations, or related disclosures are not discussed. Accounting Standards Pending Adoption ASU No. 2020-06. In August 2020, the FASB issued ASU No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity (“ASU 2020-06”), which simplifies the guidance on an issuer’s accounting for convertible instruments and contracts in its own equity. The standard is effective for the Company beginning in the first quarter of 2022, with early adoption permitted in the first quarter of 2021. The Company did not elect to early adopt the standard and does not expect ASU 2020-06 to have a material impact to its condensed consolidated financial statements.

Revenue Recognition

Revenue Recognition	6 Months Ended
	Jun. 30, 2021
Revenue from Contract with Customer [Abstract]
Revenue Recognition	Revenue Recognition During the three and six months ended June 30, 2021, the Company recognized total revenue under collaborative research and development arrangements of $75,000 and $125,000, respectively, from its affiliated entity Plumbline Life Sciences, Inc. ("PLS") and $198,000 and $519,000, respectively, from various other contracts as a result of performance obligations being satisfied. Of the total revenue recognized during the three and six months ended June 30, 2021, $35,000 and $39,000, respectively, were in deferred revenue as of December 31, 2020.

Short-term Investments

Short-term Investments	6 Months Ended
	Jun. 30, 2021
Investments, Debt and Equity Securities [Abstract]
Short-term Investments	Short-term Investments Short-term investments at June 30, 2021 consisted of mutual funds, U.S. treasury securities, certificates of deposit and U.S. agency mortgage-backed securities. Short-term investments at December 31, 2020 consisted of mutual funds, certificates of deposit and U.S. agency mortgage-backed securities. Short-term investments are recorded at fair value, based on current market valuations. Unrealized gains and losses on the Company's short-term debt investments are excluded from earnings and reported as a separate component of other comprehensive loss until realized. Realized gains and losses and unrealized gains and losses on available-for-sale equity securities are included in non-operating other income (expense) on the condensed consolidated statements of operations and are derived using the specific identification method for determining the cost of the securities sold. During the three and six months ended June 30, 2021, the Company recorded gross realized gain on investments of $358,000 and $358,000, respectively, and gross realized loss on investments of $194,000 and $204,000, respectively. During the three and six months ended June 30, 2020, the Company recorded gross realized gain on investments of $585,000 and $635,000, respectively, and gross realized loss on investments of $686,000 and $1.2 million, respectively. During the three and six months ended June 30, 2021, the Company recorded net unrealized gain (loss) on available-for-sale equity securities of $136,000 and $(711,000), respectively. During the three and six months ended June 30, 2020, the Company recorded net unrealized gain (loss) on available-for-sale equity securities of $4.4 million and $(691,000), respectively. No material balances were reclassified out of accumulated other comprehensive income (loss) for the three and six months ended June 30, 2021 and 2020. Interest and dividends on investments classified as available-for-sale are included in interest income in the condensed consolidated statements of operations. As of June 30, 2021, the Company had 22 available-for-sale securities in an unrealized loss position, of which four with an aggregate total unrealized loss of $211,000 were in such position for longer than 12 months. The following is a summary of available-for-sale securities as of June 30, 2021 and December 31, 2020: As of June 30, 2021 Contractual Cost Gross Unrealized Gross Unrealized Fair Market Value Mutual funds --- $ 207,475,699 $ 1,563,089 $ (579,056) $ 208,459,732 U.S. treasury securities Less than 1 170,203,940 10,943 (4,754) 170,210,129 Certificates of deposit Less than 1 2,972,816 25,684 — 2,998,500 U.S. agency mortgage-backed securities * 3,130,877 2,782 (49,638) 3,084,021 $ 383,783,332 $ 1,602,498 $ (633,448) $ 384,752,382 As of December 31, 2020 Contractual Cost Gross Unrealized Gross Unrealized Fair Market Value Mutual funds --- $ 153,177,675 $ 2,339,639 $ (644,140) $ 154,873,174 Certificates of deposit Less than 1 3,000,000 26,260 (10,000) 3,016,260 U.S. agency mortgage-backed securities * 3,062,256 — (36,755) 3,025,501 Total investments $ 159,239,931 $ 2,365,899 $ (690,895) $ 160,914,935 *No single maturity date. The Company periodically reviews its portfolio of available-for-sale debt securities to determine if any investment is impaired due to credit loss or other potential valuation concerns. For the debt securities where the fair value of the investment is less than the amortized cost basis, the Company has assessed at the individual security level for various quantitative factors including, but not limited to, the nature of the investments, changes in credit ratings, interest rate fluctuations, industry analyst reports, and the severity of impairment. Unrealized losses on available-for-sale debt securities as of June 30, 2021 were primarily due to changes in interest rates , and not due to increased credit risks associated with specific securities. The Company does not intend to sell these investments and it is not more likely than not that the Company will be required to sell the investments before recovery of their amortized cost basis, which may be at maturity. Based on the credit quality of the available-for-sale debt securities that are in an unrealized loss position, and the Company’s estimates of future cash flows to be collected from those securities, the Company believes the unrealized losses are not credit losses. Accordingly, at June 30, 2021, the Company has not recorded an allowance for credit losses related to its available-for-sale debt securities.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The guidance regarding fair value measurements establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value. These tiers include: Level 1, defined as observable inputs such as quoted prices in active markets that are accessible at the measurement date; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions. Assets are classified based on the lowest level of input that is significant to the fair value measurements. The Company reviews the fair value hierarchy classification on a quarterly basis. Changes in the ability to observe valuation inputs may result in a reclassification of levels for certain securities within the fair value hierarchy. The Company does not have any liabilities measured at fair value on a recurring basis and did not have any transfer of assets or liabilities between Level 1, Level 2 and Level 3 of the fair value hierarchy during the six months ended June 30, 2021 or 2020. The following table presents the Company’s assets that were measured at fair value on a recurring basis, determined using the following inputs as of June 30, 2021: Fair Value Measurements at June 30, 2021 Total Quoted Prices Significant Significant Assets: Short-term investments Mutual funds $ 208,459,732 $ 208,459,732 $ — $ — U.S. treasury securities 170,210,129 170,210,129 — — Certificates of deposit 2,998,500 — 2,998,500 — U.S. agency mortgage-backed securities 3,084,021 — 3,084,021 — Total short-term investments 384,752,382 378,669,861 6,082,521 — Investment in affiliated entity 3,908,709 3,908,709 — — Total assets measured at fair value $ 388,661,091 $ 382,578,570 $ 6,082,521 $ — The following table presents the Company’s assets that were measured at fair value on a recurring basis, determined using the following inputs as of December 31, 2020: Fair Value Measurements at December 31, 2020 Total Quoted Prices Significant Significant Assets: Cash and cash equivalents U.S. treasury securities $ 59,996,800 $ 59,996,800 $ — $ — Short-term investments Mutual funds 154,873,174 154,873,174 — — Certificates of deposit 3,016,260 3,016,260 — U.S. agency mortgage-backed securities 3,025,501 — 3,025,501 — Total short-term investments 160,914,935 154,873,174 6,041,761 — Investment in affiliated entity 4,460,366 4,460,366 — — Total assets measured at fair value $ 225,372,101 $ 219,330,340 $ 6,041,761 $ — Level 1 assets at June 30, 2021 consisted of mutual funds and U.S. treasury securities held by the Company that are valued at quoted market prices, as well as the Company’s investment in its affiliated entity, PLS. The Company accounts for its investment in 597,808 common shares of PLS based on the closing price of the shares on the Korea New Exchange Market on the applicable balance sheet date. Unrealized gains and losses on the Company's equity securities are reported in the condensed consolidated statement of ope rations as unrealized gain (loss) on available-for-sale equity securities or as a gain (loss) on investment in affiliated entities. Level 2 assets at June 30, 2021 consisted of certificates of deposit and U.S. agency mortgage-backed securities held by the Company that are initially valued at the transaction price and subsequently valued, at the end of each reporting period, typically utilizing market observable data. The Company obtains the fair value of its Level 2 assets from a professional pricing service, which may use quoted market prices for identical or comparable instruments, or inputs other than quoted prices that are observable either directly or indirectly. The professional pricing service gathers quoted market prices and observable inputs from a variety of industry data providers. The valuation techniques used to measure the fair value of the Company's Level 2 financial instruments were derived from non-binding market consensus prices that are corroborated by observable market data, quoted market prices for similar instruments, or pricing models such as discounted cash flow techniques. The Company validates the quoted market prices provided by the primary pricing service by comparing the service's assessment of the fair values of the Company's investment portfolio balance against the fair values of the Company's investment portfolio balance obtained from an independent source. There were no Level 3 assets held as of June 30, 2021.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	6 Months Ended
	Jun. 30, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets The following sets forth the goodwill and intangible assets by major asset class: June 30, 2021 December 31, 2020 Weighted Average Useful Gross Accumulated Net Book Gross Accumulated Net Book Indefinite lived: Goodwill $ 10,513,371 $ — $ 10,513,371 $ 10,513,371 $ — $ 10,513,371 Definite lived: Licenses 10 1,323,761 (1,291,226) 32,535 1,323,761 (1,276,852) 46,909 Bioject(a) 12 5,100,000 (2,608,889) 2,491,111 5,100,000 (2,468,889) 2,631,111 Other(b) 18 4,050,000 (3,693,750) 356,250 4,050,000 (3,581,250) 468,750 Total intangible assets 11 10,473,761 (7,593,865) 2,879,896 10,473,761 (7,326,991) 3,146,770 Total goodwill and intangible assets $ 20,987,132 $ (7,593,865) $ 13,393,267 $ 20,987,132 $ (7,326,991) $ 13,660,141 (a) Bioject intangible assets represent the estimated fair value of developed technology and intellectual property which were recorded from an asset acquisition. (b) Other intangible assets represent the estimated fair value of acquired intellectual property.

Convertible Debt

Convertible Debt	6 Months Ended
	Jun. 30, 2021
Debt Disclosure [Abstract]
Convertible Debt	Convertible Debt Convertible Senior Notes On February 19, 2019 and March 1, 2019, the Company completed a private placement of $78.5 million aggregate principal amount of its 6.50% convertible senior notes due 2024 (the “Notes”). The Notes were sold in a private offering to qualified institutional buyers pursuant to Rule 144A under the Securities Act of 1933, as amended. Net proceeds from the offering were approximately $75.7 million. The Notes are senior unsecured obligations of the Company and accrue interest payable in cash semi-annually in arrears on March 1 and September 1 of each year, beginning on September 1, 2019, at a rate of 6.50% per annum. The Notes will mature on March 1, 2024, unless earlier converted, redeemed or repurchased. Prior to the close of business on the business day immediately preceding November 1, 2023, the Notes will be convertible at the option of the holders only upon the satisfaction of certain circumstances. Thereafter, the Notes will be convertible at the option of the holders at any time until the close of business on the scheduled trading day immediately before the maturity date. Upon conversion, the Company will pay or deliver, as the case may be, cash, shares of its common stock or a combination of cash and shares of its common stock, at its election. The initial conversion rate will be 185.8045 shares per $1,000 principal amount of Notes (equivalent to an initial conversion price of approximately $5.38 per share), subject to adjustment upon the occurrence of specified events. The Company may not redeem the Notes prior to March 1, 2022. On or after March 1, 2022, the Company may redeem all, or any portion, of the Notes for cash if the last reported sale price per share of the Company's common stock exceeds 130% of the conversion price on (i) each of at least 20 trading days (whether or not consecutive) during the 30 consecutive trading days ending on, and including, the trading day immediately before the Company sends the related redemption notice; and (ii) the trading day immediately before the date the Company sends such redemption notice. The redemption price will be equal to 100% of the principal amount of the Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the redemption date. The Company evaluated the accounting for the issuance of the Notes and concluded that the embedded conversion features meet the requirements for a derivative scope exception for instruments that are both indexed to an entity’s own stock and classified in stockholders’ equity in its condensed consolidated balance sheet, and that the cash conversion guidance applies. Therefore, the Notes issuance proceeds of $78.5 million are allocated first to the liability component based on the fair value of non-convertible debt with otherwise identical residual terms with the residual proceeds allocated to equity for the conversion featu res. The Company determined that the fair value of the non-convertible debt upon issuance of the Notes was $62.2 million and recorded this amount as a liability and the offsetting amount as a debt discount as a reduction to the carrying value of the Notes on the closing date. The debt issuance costs associated with the Notes of $2.8 million are allocated to the liability and equity component in the same proportion as the issuance proceeds. The Company determined that all other features of the Notes were clearly and closely associated with a debt host and did not require bifurcation as a derivative liability, or the fair value of the feature was immaterial to the Company's condensed consolidated financial statements. The Company determined that the expected life of the Notes was equal to the period through November 1, 2023 as this represents the point at which the Notes are initially subject to repurchase by the Company at the option of the holders. Accordingly, the total debt discount of $18.6 million, inclusive of the fair value of the embedded conversion feature derivative at issuance, is being amortized using the effective interest method through November 1, 2023. The effective interest rate of the liability component is 13.1%. During the year ended December 31, 2020, the Company received notices for the conversion of $62.1 million of principal amount of the Notes, which were settled for an aggregate of 11,535,660 shares of the Company's common stock . The fair value of the Notes at the date of conversion was $43.7 million compared to the carrying value of $52.5 million, resulting in a $8.8 million gain on extinguishment of debt. This gain was recorded in the condensed consolidated statement of operations. To measure the fair value of the converted Notes as of the conversion dates, the Company engaged a third-party valuation expert and utilized a binomial lattice model. The balance of the Notes at June 30, 2021 is as follows: Original principal amount $ 78,500,000 Principal amount converted into common shares (62,085,000) Unamortized debt discount on the liability component (1,963,908) Unamortized debt issuance cost (270,302) Accrued interest 355,658 Net carrying amount $ 14,536,448 For the three and six months ended June 30, 2021, the Company recognized $467,000 and $930,000, respectively, of interest expense related to the Notes, of which $267,000 and $533,000, respectively, related to the contractual interest coupon. For the three and six months ended June 30, 2020 , the Company recognized $2.1 million and $4.2 million, respectively, of interest expense related to the Notes, of which $1.3 million and $2.6 million, respectively, related to the contractual interest coupon. As of June 30, 2021, future minimum payments due under the Notes, representing contractual amounts due, including interest based on the fixed rate of 6.5% per annum, are as follows: Remainder of 2021 $ 534,000 2022 1,067,000 2023 1,067,000 2024 16,948,000 Total $ 19,616,000 August 2019 Convertible Bonds On August 1, 2019, the Company closed a private placem ent of the August 2019 Bonds with an aggregate principal amount of 18 billion Korean Won (KRW) (approximately USD $15.0 million based on the exchange rate on the date of issuance) issued to institutional investors led by Korea Investment Partners (KIP), a global venture capital and private equity firm based in Seoul, Korea. Net proceeds from the offering were approximately $14.5 million. The August 2019 Bonds, which were unsecured obligations of the Company, were issued on August 1, 2019 and accrued interest at a coupon rate of 1.00% per annum, payable quarterly. The August 2019 Bonds were scheduled to mature on July 31, 2024, unless earlier converted or repurchased. On August 3, 2020 the August 2019 Bonds were converted in full into an aggregate of 4,962,364 shares of the Company's common stock, leaving no further August 2019 Bonds outstanding. The initial conversion rate was 211.0595 shares per KRW1,000,000 in principal amount (equivalent to an initial conversion price of approximately USD $4.00 per share based on the exchange rate as of July 30, 2019), subject to adjustment upon the occurrence of specified events. The conversion rate was reset on January 2, 2020 and was subject to reset quarterly thereafter if the current market price was lower than the conversion price then in effect. The conversion rate as of the date of conversion on August 1, 2020 was 275.69 shares per KRW 1,000,000 in principal amount (equivalent to a conversion price of approximately USD $3.14 per share). The Company evaluated the accounting for the issuance of the August 2019 Bonds and concluded that the embedded conversion feature was considered a derivative requiring bifurcation from the August 2019 Bonds as it did not meet the equity scope exception due to the fact that it was denominated in a currency other than the Company's functional currency. The fair value of the conversion feature at August 1, 2019 was $7.1 million, which was recorded as a reduction to the carrying value of the debt. This debt discount was being amortized to interest expense over the term of the debt using the effective interest method. The conversion option was accounted for as a derivative liability, which was revalued each reporting period with the resulting change in fair value reflected in other income (expense), net, in the condensed consolidated statements of operations. The Company determined that all other features of the August 2019 Bonds were clearly and closely associated with a debt host and did not require bifurcation as a derivative liability, or the fair value of the feature was immaterial to the Company's condensed consolidated financial statements. At their issuance, the Company determined that the expected life of the August 2019 Bonds was equal to the period through August 1, 2022 as this represented the point at which the August 2019 Bonds were initially subject to repurchase by the Company at the option of the holders. Accordingly, the total debt discount of $7.3 million, inclusive of the fair value of the embedded conversion feature derivative at issuance, was being amortized using the effective interest method through August 1, 2022 . For the three and six months ended June 30, 2020 , the Company recognized $672,000 and $1.3 million, respectively, of interest expense related to the August 2019 Bonds, of which $37,000 and $75,000, respectively, related to the contractual interest coupon. Immediately prior to the August 2020 conversion in full of the August 2019 Bonds, the derivative liability associated with the August 2019 Bonds was revalued at $84.5 million. The change in fair value of the derivative liability was an increase of $75.7 million, which was recorded on the consolidated statement of operations for the year ended December 31, 2020. To measure the fair value of the derivative liability as of the conversion date, the Company engaged a third-party valuation expert. Upon conversion, a loss on extinguishment of $8.2 million was recorded on the consolidated statement of operations for the year ended December 31, 2020. This loss represents the difference between (a) the calculated fair value of the derivative liability immediately prior to its derecognition plus the carrying amount of the debt component including any unamortized debt discount and issuance costs and (b) the fair value of the 4,692,364 shares of the Company's common stock issued upon conversion. December 2019 Convertible Bonds On December 26, 2019, the Company closed a private placement of convertible promissory notes (the “December 2019 Bonds”) with an aggregate principal amount of 4.7 billion KRW (approximately USD $4.1 million based on the exchange rate on the date of issuance) issued to a Korea-based institutional investor. Net proceeds from the offering were approximately $4.0 million. The December 2019 Bonds, which were unsecured obligations of the Company, were issued on December 31, 2019 and accrued interest at a coupon rate of 1.00% per annum, payable quarterly. The December 2019 Bonds were scheduled to mature on December 31, 2024, unless earlier converted or repurchased. On March 17, 2021, the December 2019 Bonds were converted in full into an aggregate of 1,009,450 shares of the Company's common stock, leaving no further December 2019 Bonds outstanding. The initial conversion rate was 214.7766 shares per KRW1,000,000 principal amount of Bonds (equivalent to an initial conversion price of approximately USD $4.00 per share based on the exchange rate as of December 19, 2019), subject to adjustment upon the occurrence of certain events. As of the conversion date of March 17, 2021, the conversion rate had not been reset from the initial conversion rate. The Company evaluated the accounting for the issuance of the December 2019 Bonds and concluded that the embedded conversion feature does not require bifurcation from the December 2019 Bonds. Although the embedded conversion feature meets the definition of a derivative, it qualifies for the equity scope exception for instruments that are both indexed to an entity’s own stock and classified in stockholders’ equity in its consolidated balance sheet. The December 2019 Bonds were denominated in a foreign currency other than the Company’s functional currency, which would typically violate the settlement provision criteria when analyzing whether the conversion option is indexed to an entity’s own stock. However, per the terms of the agreement, the functional currency rate required to be used in a conversion scenario was fixed as of the date preceding the date of issuance of the Bonds. Therefore, the fluctuation in functional currency did not impact the settlement of the conversion option. Further, as there was no cash conversion feature or beneficial conversion feature on the date of issuance, and the Bonds were not issued at a substantial premium, all of the proceeds were recorded as a liability. The Company determined that all other features of the December 2019 Bonds were clearly and closely associated with a debt host and did not require bifurcation as a derivative liability, or the fair value of the feature was immaterial to the Company's condensed consolidated financial statements. At their issuance, the Company determined that the expected life of the December 2019 Bonds was equal to the period through December 31, 2022 as this represented the point at which the December 2019 Bonds were initially subject to repurchase by the Company at the option of the holders. The effective interest rate of the December 2019 Bonds was 6.2% . For the six months ended June 30, 2021, the Company recognized $50,000 of interest expense related to the December 2019 Bonds, of which $9,000 related to the contractual interest coupon. For the three and six months ended June 30, 2020 , the Company recognized $60,000 and $122,000, respectively, of interest expense related to the December 2019 Bonds, of which $10,000 and $20,000, respectively, related to the contractual interest coupon.

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2021
Stockholders' Equity Note [Abstract]
Stockholders' Equity	Stockholders’ Equity The following is a summary of the Company's authorized and issued common and preferred stock as of June 30, 2021 and December 31, 2020: Outstanding as of Authorized Issued June 30, 2021 December 31, 2020 Common Stock, par value $0.001 per share 600,000,000 210,146,880 210,146,880 186,851,493 Series C Preferred Stock, par value $0.001 per share 1,091 1,091 9 9 Preferred Stock In June 2020, 14 shares of the Company’s Series C preferred stock were converted into an aggregate of 5,147 shares of the Company’s common stock. Common Stock On January 25, 2021, the Company closed an underwritten public offering of 20,355,000 shares of common stock at a public offering price of $8.50 per share. The net proceeds to the Company, after deducting the underwriters' discounts and commissions and other estimated offering expenses, were $162.1 million. In May 2018, the Company entered into a Sales Agreement with an outside placement agent (the “Placement Agent”) to sell shares of its common stock with aggregate gross proceeds of up to $100.0 million, from time to time, through an “at-the-market” equity offering program under which the Placement Agent acted as sales agent. During the first quarter of 2020, the Company and the Placement Agent entered into a first and second amendment to the Sales Agreement (the "Prior Sales Agreement") to increase the amount of common stock that may be sold under the Sales Agreement from $100.0 million to $250.0 million. As of March 31, 2020, there was no remaining capacity under the Prior Sales Agreement. On April 3, 2020, the Company and the Placement Agent entered into a new Sales Agreement (the "New Sales Agreement") to sell shares of its common stock . On April 3, 2020 and May 12, 2020, the Company filed prospectus supplements pursuant to the New Sales Agreement for the offer and sale of its Common Stock for aggregate gross proceeds of up to an aggregate of $250.0 million. During the three months ended March 31, 2020, the Company sold 43,148,952 shares of its common stock under the Prior Sales Agreement. The sales were made at a weighted average price of $4.92 per share, resulting in aggregate net proceeds of $208.2 million. As of March 31, 2020, there was no remaining capacity under the Prior Sales Agreement. During the year ended December 31, 2020, the Company sold a total of 22,919,934 shares of its common stock under the New Sales Agreement. The sales were made at a weighted average price of $10.91 per share resulting in aggregate net proceeds of $246.2 million. As of December 31, 2020, there was no remaining capacity under the New Sales Agreement. Stock Options and Restricted Stock Units The Company has a stock-based incentive plan, the 2016 Omnibus Incentive Plan (as amended to date, the "2016 Incentive Plan"), pursuant to which the Company may grant stock options, restricted stock awards, restricted stock units and other stock-based awards or short-term cash incentive awards to employees, directors and consultants. The 2016 Incentive Plan was originally approved by the Company's stockholders on May 13, 2016, and an amendment to the plan to increase the number of shares available for issuance was approved by the stockholders on May 8, 2019. As of June 30, 2021 , the maximum number of shares of the Company’s common stock available for issuance over the term of the

Net Loss Per Share

Net Loss Per Share	6 Months Ended
	Jun. 30, 2021
Earnings Per Share [Abstract]
Net Loss Per Share	Net Loss Per Share Basic net loss per share is computed by dividing the net loss for the period by the weighted average number of shares of common stock outstanding during the period. Diluted net loss per share is calculated in accordance with the treasury stock method for the outstanding stock options and restricted stock units and refle cts the potential dilution that would occur if securities or other con tracts to issue common stock were exercised or converted to common stock. The dilutive impact of the outstanding Notes and Bonds issued by the Company (discussed in Note 9) has been considered using the "if-converted" method. The calculation of diluted net loss per share requires that, to the extent the average market price of the underlying shares for the reporting period exceeds the exercise price of the options or other securities and the presumed exercise of such securities are dilutive to net loss per share for the period, an adjustment to the net loss used in the calculation is required to remove the change in fair value of such securities from the numerator for the period. Likewise, an adjustment to the denominator is required to reflect the related dilutive shares, if any. For the three and six months ended June 30, 2021 and 2020, basic and diluted net loss per share were the same, as the assumed exercise or settlement of stock options and restricted stock units and the potentially dilutive shares issuable upon conversion of the Notes and Bonds would have been anti-dilutive. The following table summarizes potential shares of common stock that were excluded from the diluted net loss per share calculation because of their anti-dilutive effect for the three and six months ended June 30, 2021 and 2020: Common Stock Equivalents 2021 2020 Options to purchase common stock 10,330,818 9,193,096 Service-based restricted stock units 2,516,102 2,868,665 Performance-based restricted stock units 663,353 — Convertible preferred stock 3,309 3,309 Convertible notes 3,049,980 14,585,653 August 2019 Bonds — 4,962,364 December 2019 Bonds — 1,009,450 Total 16,563,562 32,622,537

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2021
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based CompensationThe Company incurs stock-based compensation expense related to restricted stock units ("RSUs") and stock options. The fair value of restricted stock is determined by the closing price of the Company's common stock reported on the Nasdaq Global Select Market on the date of grant. The Company estimates the fair value of stock options granted using the Black-Scholes option pricing model. The Black-Scholes option pricing model was developed for use in estimating the fair value of traded options, which have no vesting restrictions and are fully transferable. In addition, option valuation models require the input of subjective assumptions, including the expected stock price volatility and expected option life. The Company amortizes the fair value of the awards on a straight-line basis over the requisite vesting period of the awards. Expected volatility is based on historical volatility. The expected life of options granted is based on historical expected life. The risk-free interest rate is based on the U.S. Treasury yield in effect at the time of grant. The dividend yield is based on the fact that no dividends have been paid historically and none are currently expected to be paid in the foreseeable future. The Company recognizes forfeitures as they occur. The weighted average assumptions used in the Black-Scholes model for option grants to employees and directors are presented below: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Risk-free interest rate 0.99% 0.40% 0.90% 0.67% Expected volatility 93% 80% 92% 77% Expected life in years 5.7 5.9 5.8 5.9 Dividend yield — — — — Total employee and director stock-based compensation expense recognized in the condensed consolidated statements of operations for the three and six months ended June 30, 2021 was $5.3 million and $14.5 million, respectively, of which $2.7 million and $7.9 million, respectively, was included in research and development expenses, and $2.6 million and $6.6 million, respectively, was included in general and administrative expenses. Total employee and director stock-based compensation expense recognized in the condensed consolidated statements of operations for the three and six months ended June 30, 2020 was $3.4 million and $7.1 million, respectively, of which $1.8 million and $4.1 million, respectively, was included in research and development expenses, and $1.6 million and $3.0 million, respectively, was included in general and administrative expenses. At June 30, 2021, there was $19.8 million of total unrecognized compensation expense related to unvested stock options, which is expected to be recognized over a weighted-average period of 2.3 years. The weighted average grant date fair value per share, calculated using the Black-Scholes option pricing model, was $5.25 and $7.91 for employee and director stock options granted during the three and six months ended June 30, 2021, respectively, and $9.52 and $6.19 for the three and six months ended June 30, 2020, respectively. At June 30, 2021, there was $16.8 million of total unrecognized compensation expense related to unvested service-based RSUs, which is expected to be recognized over a weighted-average period of 2.1 years. The weighted average grant date fair value per share was $6.81 and $10.64 for service-based RSUs granted during the three and six months ended June 30, 2021, respectively, and $14.50 and $9.12 for the three and six months ended June 30, 2020, respectively. The fair value of stock options granted to non-employees was estimated using the Black-Scholes pricing model. Total stock-based compensation expense for stock options and RSUs granted to non-employees for the three and six months ended June 30, 2021 was $308,000 and $737,000, respectively. Total stock-based compensation expense for stock options and RSUs granted to non-employees for the three and six months ended June 30, 2020 was $224,000 and $607,000, respectively. On August 28, 2020, the Company granted 663,353 performance-based RSUs to executives under the 2016 Incentive Plan. The RSUs will vest in two tranches as follows: 50% of the shares in each tranche will vest upon achievement of the predetermined performance milestones and the remaining 50% of the shares in each tranche will vest upon subsequent completion of a one-year service period. The total grant date fair value of the performance-based RSUs was $8.0 million based on the grant date closing price per share of $12.06. As of June 30, 2021 , the underlying performance milestones of the RSUs were not probable of achievement, and no stock-based compensation expense was recognized for the performance-based RSUs for the six months then ended.

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 2021
Related Party Transaction, Due from (to) Related Party [Abstract]
Related Party Transactions	Related Party Transactions Plumbline Life Sciences, Inc. The Company owned 597,808 shares of common stock in PLS as of June 30, 2021, representing a 19.7% ownership interest, and one of the Company's directors, Dr. David B. Weiner, acts as a consultant to PLS. Revenue recognized from PLS consists of milestone, license and patent fees. For the three and six months ended June 30, 2021, the Company recognized revenue from PLS of $75,000 and $125,000, respectively, and $64,000 and $1.2 million, for the three and six months ended June 30, 2020, respectively. At June 30, 2021 and December 31, 2020, the Company had an accounts receivable balance of $99,000 and $67,000, respectively, related to PLS. The Wistar Institute The Company's director Dr. David B. Weiner is a director of the Vaccine Center of The Wistar Institute ("Wistar"). Dr. Weiner is also the Executive Vice President of Wistar. In March 2016, the Company entered into collaborative research agreements with Wistar for preventive and therapeutic DNA-based immunotherapy applications and products developed by Dr. Weiner and Wistar for the treatment of cancers and infectious diseases. Under the terms of the agreement, the Company reimbursed Wistar for all direct and indirect costs incurred in the conduct of the collaborative research, not to exceed $3.1 million during the five-year term of the agreements. In March 2021, upon expiration of the March 2016 agreements, the Company entered into new collaborative research agreements with Wistar with the same terms. The Company has the exclusive right to in-license new intellectual property developed under the agreements. In November 2016, the Company received a $6.1 million sub-grant through Wistar to develop a dMAb against the Zika infection, with funding extended through December 2021. The Company is also a collaborator with Wistar on an Integrated Preclinical/Clinical AIDS Vaccine Development grant from the NIAID, with funding through February 2022. In 2020, the Company received a $10.7 million sub-grant through Wistar for the preclinical development and translational studies of dMAbs as countermeasures for COVID-19, with funding through September 2022. The sub-grant also includes an option for an additional $6.0 million in funding through September 2024. Deferred grant funding recognized from Wistar and recorded as contra-research and development expense is related to work performed by the Company on the research sub-contract agreements. For the three and six months ended June 30, 2021, the Company recorded $381,000 and $610,000, respectively, and for the three and six months ended June 30, 2020 the Company recorded $73,000 and $691,000, respectively, as contra-research and development expense from Wistar. Research and development expenses recorded from Wistar relate primarily to the collaborative research agreements and sub-contract agreements related to the Bill & Melinda Gates Foundation and CEPI (see Note 15). Research and development expenses recorded from Wistar for the three and six months ended June 30, 2021 were $1.2 million and $1.6 million, respectively. Research and development expenses recorded from Wistar for the three and six months ended June 30, 2020 were $408,000 and $770,000, respectively. At June 30, 2021 and December 31, 2020, the Company had an accounts receivable balance of $617,000 and $425,000, respectively, and an accounts payable and accrued liability balance of $1.8 million and $643,000, respectively, related to Wistar. As of June 30, 2021, the Company had a prepaid expense balance of $303,000 and recorded $69,000 as deferred grant funding on the condensed consolidated balance sheet related to Wistar.

Leases

Leases	6 Months Ended
	Jun. 30, 2021
Leases [Abstract]
Leases	Leases The Company leases approximately 82,200 square feet of office, laboratory, and manufacturing space in San Diego, California and 57,360 square feet of office space in Plymouth Meeting, Pennsylvania under various non-cancellable operating lease agreements with remaining lease terms as of June 30, 2021 of 2.4 to 8.5 ye ars, which represent the non-cancellable periods of the leases. The Company has excluded the extension options from its lease terms in the calculation of future lease payments as they are not reasonably certain to be exercised. The Company's lease payments consist primarily of fixed rental payments for the right to use the underlying leased assets over the lease terms as well as payments for common area maintenance and administrative services. The Company has received customary incentives from its landlords, such as reimbursements for tenant improvements and rent abatement periods, which effectively reduce the total lease payments owed for these leases. The Company performed an evaluation of its contracts with customers and suppliers in accordance with ASC Topic 842 and determined that, except for the real estate leases described above and various copier leases, none of its other contracts contain a right-of-use asset. Operating lease right-of-use assets and liabilities on the condensed consolidated balance sheet represents the present value of the remaining lease payments over the remaining lease terms. Payments for additional monthly fees to cover the Company's share of certain facility expenses are not included in operating lease right-of-use assets and liabilities. The Company uses its incremental borrowing rate to calculate the present value of its lease payments, as the implicit rates in the leases are not readily determinable. As of June 30, 2021, the maturities of the Company's operating lease liabilities were as follows: Remainder of 2021 $ 1,994,000 2022 4,045,000 2023 4,023,000 2024 3,001,000 2025 3,063,000 Thereafter 9,888,000 Total remaining lease payments 26,014,000 Less: present value adjustment (6,753,000) Total operating lease liabilities 19,261,000 Less: current portion (2,464,000) Long-term operating lease liabilities $ 16,797,000 Weighted-average remaining lease term 7.0 years Weighted-average discount rate 8.5% Lease costs included in operating expenses in the condensed consolidated statements of operations for the three and six months ended June 30, 2021 were $827,000 and $1.7 million, respectively. Lease costs included in operating expenses in the condensed consolidated statements of operations for the three and six months ended June 30, 2020 were $814,000 and $1.7 million, respectively. Operating lease costs consisting of the fixed lease payments included in operating lease liabilities are recorded on a straight-line basis over the lease terms. Variable lease costs are recorded as incurred. In the fourth quarter of 2019, the Company entered into two agreements to sublease a total of approximately 13,500 square feet in its Plymouth Meeting headquarters through periods between December 31, 2022 and March 31, 2025. In the normal course of business, the Company is a party to a variety of agreements pursuant to which it may be obligated to indemnify the other party. It is not possible to predict the maximum potential amount of future payments under these types of agreements due to the conditional nature of the Company's obligations and the unique facts and circumstances involved in each particular agreement. Historically, payments made by the Company under these types of agreements have not had a material effect on its business, consolidated results of operations or financial condition.

Collaborative Agreements

Collaborative Agreements	6 Months Ended
	Jun. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaborative Agreements	Collaborative Agreements Advaccine Biopharmaceuticals Suzhou Co., Ltd. On December 31, 2020, the Company entered into a Collaboration and License Agreement with Advaccine Biopharmaceuticals Suzhou Co., Ltd. (“Advaccine”), which was amended and restated on June 7, 2021 (as amended and restated, the “Advaccine Agreement”). Under the terms of the Advaccine Agreement, the Company granted to Advaccine the exclusive right to develop, manufacture and commercialize the Company’s vaccine candidate INO-4800 within the territories of China, Taiwan, Hong Kong and Macau (referred to collectively as “Greater China”) and 33 additional countries in Asia. Advaccine does not have the right to grant sublicenses, other than to affiliated entities, without the Company’s express prior written consent. As part of the collaboration, Advaccine also granted to the Company a non-exclusive license to certain DNA vaccine manufacturing processes. The June 2021 amendment relates to the collaboration between the Company and Advaccine to jointly conduct the global Phase 3 segment of the Company’s ongoing Phase 2/3 trial of INO-4800 and expand the existing collaboration to include the planned global Phase 3 trial. The parties will jointly participate in the trial and will equally share the global development costs for the trial, including the Company’s manufacturing costs to supply INO-4800. In certain instances, the Company will have the right to convert the exclusive license to a non-exclusive license in the licensed territories, other than Greater China, unless Advaccine agrees to pay the Company its full share of development costs in excess of a specified maximum. Notwithstanding the foregoing, Advaccine will be fully responsible for conducting the trial in Greater China, including its costs and expenses incurred in conducting the trial in Greater China. The Company will be fully responsible for its costs and expenses, if any, incurred solely as a result of its activities in connection with the performance of the trial in the United States. The parties may continue to conduct clinical trials of INO-4800 outside of the territories covered by the Advaccine Agreement. In the event that a global purchasing entity desires to enter into a purchase agreement for INO-4800 in both parties’ territories, the parties will enter into good faith negotiations for an arrangement to supply INO-4800 to such entity. In addition, the Company is permitted to enter into an agreement with a global purchasing entity to authorize the entity to conduct a portion of the global Phase 3 trial in the licensed territory outside of Greater China. Under the Advaccine Agreement, Advaccine made an upfront payment to the Company of $3.0 million in January 2021. In addition to the upfront payment, the Company is entitled to receive up to an aggregate of $206.0 million upon the achievement of specified milestones related to the development, regulatory approval and commercialization of INO-4800, including the achievement of specified net sales thresholds for INO-4800 in Greater China and the additional covered territories, if approved. As of December 31, 2020 the Company had earned a $2.0 million milestone payment based on the enrollment of the first subject in the Phase 2 clinical trial for the product in the Advaccine territory. The Company will also be entitled to receive a royalty equal to a high single-digit percentage of annual net sales in each region within the licensed territory, subject to reduction in the event of competition from biosimilar products in a particular region and in other specified circumstances. Advaccine’s obligation to pay royalties will continue, on a licensed product-by-licensed product basis and region-by-region basis, for ten years after the first commercial sale in a particular region within Greater China or, if later, until the expiration of the last-to-expire patent covering a given licensed product in a given region. Beginning in the first calendar year following the first commercial sale of INO-4800 in the licensed territory outside of Greater China, Advaccine will pay the Company an annual maintenance fee of $1.5 million for a period of five years, which fee will be creditable against any royalties payable by Advaccine with respect to sales outside of Greater China. Under the Advaccine Agreement, the Company will supply Advaccine’s clinical requirements of INO-4800 and devices, although Advaccine may manufacture INO-4800 for its clinical use and may procure alternate suppliers. Advaccine is responsible for the manufacture and supply of INO-4800 itself or through a contract manufacturer for commercial use. Upon Advaccine’s reasonable request, the parties may negotiate a separate clinical and/or commercial supply agreement. The Advaccine Agreement will continue in force on a region-by-region basis until Advaccine has no remaining royalty obligations in such region. Either party may terminate the Advaccine Agreement (i) in the event the other party shall have materially breached its obligations thereunder and such default shall have continued for a specified period after written notice thereof or (ii) upon the bankruptcy or insolvency of the other party. In addition, the Company may terminate the agreement, upon prior written notice, if Advaccine (i) ceases all development or commercialization activities for at least nine months, subject to certain exceptions, or (ii) challenges the validity, enforceability or scope of any of the patents licensed by the Company to Advaccine under the Advaccine Agreement, subject to certain conditions. Advaccine may terminate the Advaccine Agreement at any time for convenience upon nine months’ written notice to the Company, if such notice is provided before the first commercial sale of INO-4800 in the licensed territory, or 18 months’ written notice thereafter; provided that the Company may accelerate the effectiveness of such termination to the extent permitted by law. The Company evaluated the terms of the Advaccine Agreement under ASC Topics 606 and 808 at inception and determined that the contract was with a customer and therefore should be accounted for under ASC Topic 606. The license to INO-4800 in the territories was identified as the only distinct performance obligation on a standalone basis as of the inception of the Advaccine Agreement. The Company concluded that the license was distinct from potential future manufacturing and supply obligations. The Company further determined that the transaction price under the Advaccine Agreement consisted of the $3.0 million upfront payment plus the initial $2.0 million milestone payment which was achieved upon contract signing. The future potential milestone amounts were not included in the transaction price, as they were all determined to be fully constrained. As part of the evaluation of the development and regulatory milestones constraint, the Company determined that the achievement of such milestones is contingent upon success in future clinical trials and regulatory approvals, each of which is uncertain. Future potential milestone amounts may be recognized as revenue under the Advaccine Agreement, as well as under other collaborative research and development arrangements, if unconstrained. Reimbursable program costs will be recognized proportionately with the performance of the underlying services or delivery of drug supply and are excluded from the transaction price. Under Topic 606, the entire transaction price of $5.0 million was allocated to the license performance obligation. The Company determined that as of December 31, 2020, the transfer of technology has occurred for the use and benefit of the license and accordingly, the performance obligation was fully satisfied. The Company accordingly recognized $5.0 million in revenue under collaborative research and development arrangements on the consolidated statement of operations during the year ended December 31, 2020. For the six months ended June 30, 2021, no revenue was recognized from Advaccine. As of June 30, 2021 and December 31, 2020 , the Company had an accounts receivable balance of $0 and $7.1 million, respectively, from Advaccine. The Company reevaluated the Advaccine Agreement under ASC Topics 606 and 808 as of the date of the June 2021 amendments and determined that the Global Phase 3 trial component of the agreement is a collaboration and not a contract with a customer and therefore should be accounted for under ASC Topic 808. Reimbursements from Advaccine will be recognized as contra-research development expense on the condensed consolidated statement of operations once earned and collectibility is assured. As of June 30, 2021, no contra-research and development expense has been recorded from Advaccine. ApolloBio Corporation On December 29, 2017, the Company entered into an Amended and Restated License and Collaboration Agreement (the "ApolloBio Agreement"), with ApolloBio Corporation ("ApolloBio"), with an effective date of March 20, 2018. Under the terms of the ApolloBio Agreement, the Company has granted to ApolloBio the exclusive right to develop and commercialize VGX-3100, its DNA immunotherapy product candidate designed to treat pre-cancers caused by HPV, within the territories of China, Hong Kong, Macao, Taiwan, and potentially Korea in the event that no patent covering VGX-3100 is issued in China within the three years following the effective date of the ApolloBio Agreement. Under the ApolloBio Agreement, the Company received proceeds of $19.4 million in March 2018 which comprised the upfront payment of $23.0 million less $2.2 million in foreign income taxes and $1.4 million in certain foreign non-income taxes. The foreign income taxes were recorded as a provision for income taxes and the foreign non-income taxes were recorded as a general and administrative expense, on the condensed consolidated statement of operations. The Company also incurred advisory fees of $960,000 in connection with receiving the upfront payment from ApolloBio. These fees were determined to be incremental costs of obtaining the contract. The Company applied the practical expedient that permits a company to expense incremental costs to obtain a contract when the expected amortization period is one year or less and recorded the fees in general and administrative expense during the quarter ended March 31, 2018. No additional advisory fees are due related to the ApolloBio Agreement. In addition to the upfront payment, the Company is entitled to receive up to an aggregate of $20.0 million, less required income, withholding or other taxes, upon the achievement of specified milestones related to the regulatory approval of VGX-3100 in the United States, China and Korea. In the event that VGX-3100 is approved for marketing, the Company will be entitled to receive royalty payments based on a tiered percentage of annual net sales, with such percentage being in the low- to mid-teens, subject to reduction in the event of generic competition in a particular territory. ApolloBio’s obligation to pay royalties will continue for 10 years after the first commercial sale in a particular territory or, if later, until the expiration of the last-to-expire patent covering the licensed products in the specified territory. The ApolloBio Agreement will continue in force until ApolloBio has no remaining royalty obligations. Either party may terminate the ApolloBio Agreement in the event the other party shall materially breach or default in the performance of its material obligations thereunder and such default continues for a specified period after written notice thereof. In addition, ApolloBio may terminate the ApolloBio Agreement at any time beginning one year after the effective date for any reason upon 90 days written notice to the Company. The Company evaluated the terms of the ApolloBio Agreement under ASC Topic 606, and the license to VGX-3100 in the territories was identified as the only distinct performance obligation on a standalone basis as of the inception of the agreement. The Company concluded that the license was distinct from potential future manufacturing and supply obligations. The Company further determined that the transaction price under the agreement consisted of the $23.0 million upfront payment. The future potential milestone amounts were not included in the transaction price, as they were all determined to be fully constrained. As part of the evaluation of the development and regulatory milestones constraint, the Company determined that the achievement of such milestones is contingent upon success in future clinical trials and regulatory approvals, each of which is uncertain at this time. Future potential milestone amounts may be recognized as revenue under the ApolloBio Agreement, as well as under other collaborative research and development arrangements, if unconstrained. Reimbursable program costs will be recognized proportionately with the performance of the underlying services or delivery of drug supply and are excluded from the transaction price. As of June 30, 2021 there have been no significant reimbursable program costs under the ApolloBio Agreement. Under Topic 606, the entire transaction price of $23.0 million was allocated to the license performance obligation. The Company determined that during the quarter ended June 30, 2018, the transfer of technology occurred and accordingly, the performance obligation was fully satisfied. AstraZeneca On August 7, 2015, the Company entered into a license and collaboration agreement with MedImmune, the global biologics research and development arm of AstraZeneca ("AstraZeneca"). Under the agreement, AstraZeneca acquired exclusive rights to the Company's INO-3112 immunotherapy, renamed as MEDI0457, which targets cancers caused by human papillomavirus (HPV) types 16 and 18, with the ability to sublicense those license rights. AstraZeneca made an upfront payment of $27.5 million to the Company in September 2015. AstraZeneca may be obligated to make potential future development and regulatory event-based payments to the Company totaling up to $125 million and potential future commercial event-based payments totaling up to $115 million, in each case upon the achievement of specified milestones related to MEDI0457 set forth in the license and collaboration agreement. AstraZeneca will fund all development costs associated with MEDI0457 immunotherapy. The Company is entitled to receive up to mid-single to double-digit tiered royalties on MEDI0457 product sales. Under the agreement, AstraZeneca can also request the Company to provide certain clinical manufacturing at an agreed upon price. The Company determined these options did not represent material rights at the inception of the agreement. As of December 31, 2017, the Company had recognized all of the $27.5 million upfront payment as revenue, as all identified material performance obligations had been met with respect to that payme nt. In both December 2018 and March 2019, the Company recognized as revenue $2.0 million in milestone payments from AstraZeneca triggered by AstraZeneca’s initiation of the Phase 2 portion of ongoing clinical trials in the second and third major indication, respectively, under the agreement. Coalition for Epidemic Preparedness Innovations In April 2018, the Company entered into agreements with CEPI, pursuant to which the Company intends to develop vaccine candidates against Lassa fever and MERS. The goal of the collaboration between the Company and CEPI is to conduct research and development so that investigational stockpiles will be ready for clinical efficacy trial testing during potential disease outbreaks. The agreements with CEPI contemplate preclinical studies, as well as Phase 1 and Phase 2 clinical trials, occurring over multiple years. As part of the arrangement between the parties, CEPI has agreed to fund up to an aggregate of $56 million of costs over a five-year period for preclinical studies, as well as planned Phase 1 and Phase 2 clinical trials, to be conducted by the Company and collaborators, with funding from CEPI based on the achievement of identified milestones. During the three and six months ended June 30, 2021, the Company received funding of $2.1 million and $4.4 million, respectively, related to these grants and recorded those payments as contra-research and development expense. During the three and six months ended June 30, 2020, the Company received funding of $1.8 million and $2.9 million, respectively, related to these grants and recorded those payments as contra-research and development expense. As of June 30, 2021, the Company had $316,000 recorded as grant funding liability on the condensed consolidated balance sheet related to these CEPI grants. In January 2020, CEPI awarded the Company a grant of up to $9.0 million to support preclinical and clinical development of INO-4800 through Phase 1 human testing in the United States. In April 2020, CEPI awarded the Company a grant of $6.9 million to work with the International Vaccine Institute ("IVI") and the Korea National Institute of Health ("KNIH") to conduct clinical trials of INO-4800 in South Korea, a grant of $5.0 million to accelerate development of the Company's next-generation intradermal electroporation device, known as CELLECTRA ® 3PSP, for the intradermal delivery of INO-4800, and a grant of $1.3 million to support large-scale manufacturing of INO-4800. During the three and six months ended June 30, 2021, the Company received funding of $1.1 million and $3.5 million, respectively, from CEPI related to these grants for INO-4800 and recorded such amounts as contra-research and development expense. During the three and six months ended June 30, 2020, the Company received funding of $5.8 million and $8.1 million, respectively, from CEPI related to these grants for INO-4800 and recorded such amounts as contra-research and development expense. As of June 30, 2021, the Company had $2.9 million recorded as deferred grant funding on the condensed consolidated balance sheet from the CEPI grants related to INO-4800. Bill & Melinda Gates Foundation In October 2018, the Bill & Melinda Gates Foundation (“Gates”) awarded and funded the Company a grant of $2.2 million to advance the development of dMAbs to address issues in infectious disease prevention and therapy. This technology has high relevance for the control of influenza and HIV. This next-generation approach to the delivery of monoclonal antibodies would make the technology accessible to low and middle-income countries. In August 2019, Gates funded an additional $1.1 million for the project. During the three and six months ended June 30, 2020, the Company recorded $36,000 and $170,000, respectively, as contra-research and development expense related to the Gates dMAb grant. During the three and six months ended June 30, 2021, the amounts recorded were minimal. As of June 30, 2021, the Company had $575,000 recorded as deferred grant funding on the condensed consolidated balance sheet related to the grant. In March 2020, Gates awarded and funded the Company a grant of $5.0 million to accelerate the development of the CELLECTRA ® 3PSP device for the intradermal delivery of INO-4800. During the three and six months ended June 30, 2021, the Company recorded $0 and $893,000, respectively, and during the three and six months ended June 30, 2020 recorded $850,000 and $913,000, respectively, as contra-research and development expense related to this Gates grant. Department of Defense (DoD) In June 2020, the Company entered into an Other Transaction Authority for Prototype Agreement (the “OTA Agreement”) with the DoD to fund the Company’s efforts in developing the CELLECTRA ® 3PSP device and associated arrays to be used for delivery of INO-4800 against COVID-19. Under the OTA Agreement, the Company intends to develop the CELLECTRA ® 3PSP device and arrays for use in the U.S. military population and the U.S. population as a whole, subject to approval of the device by the U.S. Food and Drug Administration (the “FDA”). The OTA Agreement is also expected to support large-scale manufacturing of the CELLECTRA ® 3PSP device, as well as large-scale DNA plasmid production for manufacture and supply of a specified number of doses of INO-4800 in support of FDA approval of the device. The total amount of funding being made available to the Company under the OTA Agreement is approximately $54.5 million. The Company has determined that the OTA Agreement should be considered under Subtopic 958-605, Not-for-Profit Entities Revenue Recognition , which is outside the scope of Topic 606, as the government agency granting the Company funds is not receiving reciprocal value for their contributions. The Company will record contra-research development expense on the condensed consolidated statement of operations in the same period that the underlying expenses are incurred. Additionally, in June 2020, the Company was awarded a fixed-price contract (the “Procurement Contract”) from the DoD for the purchase of the Company’s intradermal CELLECTRA ® 2000 device and accessories. The CELLECTRA ® 2000 devices will be used to inject INO-4800 in the Company’s planned later-stage clinical trials. The total purchase price under the Procurement Contract is approximately $16.6 million. The Company has determined that the Procurement Contract does not currently fall under the scope of ASC 606 as contingencies remain regarding INO-4800 which does not give the Company the ability to satisfy its obligations under the arrangement. During the three and six months ended June 30, 2021, the Company recorded $13.4 million and $21.2 million, respectively, as contra-research and development expense related to the OTA Agreement. During the three and six months ended June 30, 2020, there was no contra-research and development expense recorded related to the OTA Agreement. As of June 30, 2021 and December 31, 2020, the Company had an accounts r eceivable balance of $12.9 million and $11.4 million, respectively, on the condensed consolidated balance sheet from the DoD. As of June 30, 2021, the Company had $3.0 million recorded as deferred grant funding on the condensed consolidated balance sheet related to the Procurement Contract. In April 2021, the Company announced that the DoD had notified the Company that it will discontinue funding f or the Phase 3 segment of the Company's clinical trial of INO-4800 in the United States, while continuing to fund the completion of the ongoing Phase 2 segment.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company uses an estimated annual effective tax rate, which is based on expected annual income, statutory tax rates and tax planning opportunities available in the various jurisdictions in which the Company operates, to determine its quarterly provision for income taxes. Certain significant or unusual items are separately recognized in the quarter in which they occur and can be a source of variability in the effective tax rates from quarter to quarter. Due to the adoption of ASU 2019-12 which removes the exception under ASC 740-20-45-7 to consider all sources of income in order to determine the tax benefit resulting from a loss from continuing operations, ASC 740-20-45-7 no longer applies.On March 27, 2020, the United States enacted the Coronavirus Aid, Relief and Economic Security Act (CARES Act).  The CARES Act is an emergency economic stimulus package that includes spending and tax breaks to strengthen the United States economy and fund a nationwide effort to curtail the effect of COVID-19. The CARES Act provides sweeping tax changes in response to the COVID-19 pandemic; some of the more significant provisions are removal of certain limitations on utilization of net operating losses, increasing the loss carryback period for certain losses to five years, and increasing the ability to deduct interest expense, as well as amending certain provisions of the previously enacted Tax Cuts and Jobs Act. For the three and six months ended June 30, 2021, the Company has not recorded any income tax provision/(benefit) due to the Company’s history of net operating losses generated and the maintenance of a full valuation allowance against its net deferred tax assets.

Geneos Therapeutics, Inc.

Geneos Therapeutics, Inc.	6 Months Ended
	Jun. 30, 2021
Noncontrolling Interest [Abstract]
Geneos Therapeutics, Inc.	Geneos Therapeutics, Inc. In August 2016, the Company formed Geneos to develop and commercialize neoantigen-based personalized cancer therapies. Geneos was considered a variable interest entity (VIE) for which the Company was the primary beneficiary. In February 2019, Geneos completed the initial closing of a Series A preferred stock financing. The Company invested $1.2 million in the Series A preferred stock financing, which was led by an outside investor. Following this transaction, the Company held 61% of the outstanding equity, on an as-converted to common stock basis, of Geneos and continued to consolidate its investment in Geneos under ASC 810, Consolidation . In January 2020, Geneos completed the second closing of the Series A preferred stock financing, in which the Company invested $800,000. Following this transaction, as of March 31, 2020, the Company held 52% of the outstanding equity, on an as-converted to common stock basis, of Geneos and continued to consolidate its investment in Geneos. In June 2020, Geneos closed an additional Series A preferred stock financing round, in which the Company invested $800,000. Following this transaction, the Company owned 47% of the outstanding equity of Geneos on an as-converted to common stock basis. This transaction triggered a VIE reconsideration, as the Company no longer held a controlling financial interest. Based on the Company’s assessment, Geneos continued to be a VIE as it did not have sufficient equity at risk to finance its activities without additional subordinated financial support. However, the Company was not the primary beneficiary of Geneos, as it did not have the power to direct the activities that most significantly impact Geneos’ economic performance. Accordingly, the Company deconsolidated its investment in Geneos as of June 1, 2020, resulting in a gain of $4.1 million, of which $2.4 million related to the remeasurement of the retained noncontrolling interest investment to fair value. The gain has been recorded separately on the Company's condensed consolidated statement of operations. The following table shows the amounts related to the deconsolidation accounting: Working capital (excluding cash) $ (59,992) Note payable 171,620 Fixed assets, net of accumulated depreciation (16,340) Carrying value of noncontrolling interest 3,181,640 Fair value of investment in Geneos retained 3,618,998 Gain on deconsolidation of Geneos (4,121,075) Decrease in cash resulting from the deconsolidation of Geneos $ 2,774,851 The details of the Company’s 47% retained equity investment in Geneos is shown in the table below, with fair values calculated as of June 1, 2020, the date of deconsolidation. Geneos Share Class Shares Price per Share Fair Value Common 3,000,000 $ 0.273 $ 819,000 Preferred 2,113,206 $ 1.325 $ 2,799,998 Total 5,113,206 $ 3,618,998 The fair value of Geneos Series A preferred stock was based on the per share price paid by third-party investors in connection with the most recent closing of the Series A preferred stock financing for Geneos on June 1, 2020. The fair value of Geneos common stock was determined by a third-party valuation, as there is no public market for such stock. Geneos’ enterprise value, which was estimated using a market approach that derived an implied total equity value from a transaction involving its own securities, was allocated to all classes of equity using the option pricing method. Under the option pricing method, each equity class was modeled as having a call option with a distinct claim on the total value of Geneos. Each option’s exercise price was based on the total value available for each participating security holder. The characteristics of each class of ownership determined the claim on the total value for that class of ownership. The estimated value allocated to common stock included assumptions related to the fair value of the enterprise, expected volatility, expected term, and risk-free interest rate. Expected volatility was based on historical asset volatilities derived from daily stock price changes of guideline public companies. The estimated expected term was based on a weighted average of the estimated time to Geneos's next financing and successful exit timing assumption. The risk-free interest rate was based on the yield of U.S. Treasury with a comparable term. Geneos’s common stock is classified as a Level 3 financial instrument. The assumptions used in the fair value calculation as of June 1, 2020 are presented below: Expected term (years) 2.92 Volatility 70% Risk-free interest rate 2.46% Geneos enterprise value $4,966,531 The Company applies the equity method to investments in common stock and to other investments in entities that have risk and reward characteristics that are substantially similar to an investment in the investee’s common stock. Since the Company’s Series A preferred stock investment in Geneos has a substantive liquidation preference, it is not substantially similar to the Company’s common stock investment and will therefore be recorded as an equity security under ASC 321. As of June 1, 2020, the Company accounts for its common stock investment in Geneos, in which the Company lacks control but does have the ability to exercise significant influence over operating and financial policies, using the equity method. Generally, the ability to exercise significant influence is presumed when the investor possesses more than 20% of the voting interests of the investee. This presumption may be overcome based on specific facts and circumstances that demonstrate that the ability to exercise significant influence is restricted. In applying the equity method, the Company records the investment at cost unless the initial recognition is the result of the deconsolidation of a subsidiary, in which case it is recorded at fair value. The Company's proportionate share of net loss of Geneos is recorded in equity in net earnings of Geneos in the Company's condensed consolidated statements of operations. The Company's equity method investments are reviewed for indicators of impairment at each reporting period and are written down to fair value if there is evidence of a loss in value that is other-than-temporary. Any difference between the carrying amount of the Company’s investment and the amount of underlying equity in Geneos’ net assets is amortized into income or expense accordingly. There were no basis differences identified as of the deconsolidation date that would need to be amortized. Upon deconsolidation, the Company recorded its Series A preferred stock investment at fair value based on the per share price paid by third party investors in connection with the preferred stock financing on June 1, 2020. The Company has determined that its Series A preferred stock investment in Geneos does not have a readily determinable fair value and has therefore elected the measurement alternative in ASC 321 to subsequently record the investment at cost, less any impairments, plus or minus changes resulting from observable price changes in orderly transactions for identical or similar investments of the same issuer. When fair value becomes determinable, from observable price changes in orderly transactions, the Company’s investment will be marked to fair value. There have been no observable price changes or impairments identified since the deconsolidation date. In November 2020, Geneos completed the closing of a Series A-1 preferred stock financing. The Company invested $1.4 million in the Series A-1 preferred stock financing, which was led by outside investors. The closing date of this transaction was determined to be a VIE reconsideration event; based on the Company’s assessment, Geneos continues to be a VIE as it does not have sufficient equity at risk to finance its activities without additional subordinated financial support. The Company continues to not be the primary beneficiary of Geneos, as it does not have the power to direct the activities that most significantly impact Geneos’s economic performance and should not consolidate Geneos. Following this transaction, the Company held approximately 36% of the outstanding equity, on an as-converted to common stock basis. Accordingly, the Company continues to account for its common stock investment in Geneos as an equity method investment under ASC 323 and its preferred stock investments as equity securities under ASC 321. The fair value of Geneos’s Series A-1 preferred stock was based on the per share price paid by third-party investors in connection with the closing on November 12, 2020. The Company has concluded that its Series A-1 preferred stock investment is not similar to its prior Series A preferred stock investment due to certain material rights held solely by Series A preferred stockholders. Therefore, the Company will continue to record its Series A preferred stock investment in Geneos at cost, as there have been no observable price changes or impairments identified since the deconsolidation date. The Company’s share of net losses of Geneos for the period from June 1, 2020 through December 31, 2020 was $4.6 million and for the three months ended March 31, 2021 was $1.5 million; however, only $434,000 was recorded, reducing the Company's total investment in Geneos to $0. Of the total amount, $819,000 has been allocated to the equity method investment, thereby reducing the balance to $0 as of March 31, 2021. The remaining $4.2 million loss has been allocated to the Company’s Series A and Series A-1 preferred stock investment in Geneos, on a ratable basis, thereby reducing the balance to $0 as of March 31, 2021 as shown in the table below: Investment in Geneos upon deconsolidation $ 3,618,998 Investment in Geneos Series A-1 preferred stock 1,399,999 Share in net loss of Geneos from June 1, 2020 - December 31, 2020 (4,584,610) Share in net loss of Geneos for the three months ended March 31, 2021 (434,387) Investment in Geneos as of March 31, 2021 $ — The Company will not reduce its investment below $0 and will not record its share of further net losses of Geneos as the Company has no obligation to fund Geneos. In February 2021, Geneos completed a second closing of the Series A-1 preferred stock financing, in which the Company did not participate. Following this transaction, the Company held approximately 35% of the outstanding equity, on an as-converted to common stock basis. The Company continues to exclusively license its SynCon ® immunotherapy and CELLECTRA ®

Basis of Presentation, Liquid_2

Basis of Presentation, Liquidity and Risks and Uncertainties (Policies)	6 Months Ended
	Jun. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements of Inovio have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) as contained in the Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC") for interim financial information and with instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. The condensed consolidated balance sheet as of June 30, 2021, the condensed consolidated statements of operations, the condensed consolidated statements of comprehensive loss and the condensed consolidated statements of stockholders' equity for the three and six months ended June 30, 2021 and 2020 and the condensed consolidated statements of cash flows for the six months ended June 30, 2021 and 2020 are unaudited, but include all adjustments (consisting of normal recurring adjustments) that the Company considers necessary for a fair presentation of the financial position, results of operations, cash flows and changes in stockholders' equity for the periods presented. The results of operations for the three and six months ended June 30, 2021 shown herein are not necessarily indicative of the results that may be expected for the year ending December 31, 2021, or for any other period. These unaudited financial statements, and notes thereto, should be read in conjunction with the audited consolidated financial statements for the year ended December 31, 2020, included in the Company's Annual Report on Form 10-K filed with the U.S. Securities and Exchange Commission (“SEC”) on March 1, 2021. The balance sheet at December 31, 2020 has been derived from the audited financial statements at that date, but does not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In June 2020, the Company formed a wholly-owned subsidiary, Inovio Asia LLC, under the laws of South Korea, through which the Company intends to advance its corporate development projects and other functions in South Korea and other Asian countries. These unaudited condensed consolidated financial statements include the accounts of Inovio Pharmaceuticals, Inc. and its subsidiarie s. As of June 30, 2021, the Company consolidated its wholly-owned subsidiary Inovio Asia LLC. On December 31, 2020, former wholly-owned subsidiaries Genetronics, Inc. and VGX Pharmaceuticals Inc. and former majority-owned subsidiary VGX Animal Health, Inc. were merged into Inovio Pharmaceuticals, Inc. All intercompany accounts and transactions were eliminated upon consolidation. As of June 1, 2020, the Company deconsolidated its former subsidiary Geneos Therapeutics, Inc. ("Geneos"), as the Company no longer held a controlling financial interest. Refer to Footnote 17 for further discussion. Liquidity The Company incurred a net loss attributable to common stockholders of $82.1 million and $136.5 million for the three and six months ended June 30, 2021, respectively. The Company had working capital of $490.7 million and an accumulated deficit of $1.0 billion as of June 30, 2021. The Company has incurred losses in each year since its inception and expects to continue to incur significant expenses and operating losses for the foreseeable future in connection with the research and preclinical and clinical development of its product candidates. The Company’s cash, cash equivalents and short-term investments of $443.7 million as of June 30, 2021 are sufficient to support the Company's operations for a period of at least 12 months from the date of issuance of these financial statements. In order to continue to fund future research and development activit ies, the Company will need to seek additional capital. This may occur through strategic alliance and licensing arrangements, grant agreements and/or future public or private debt or equity financings including use of potential future At-the-Market Equity Offering Sales Agreements (“Sales Agreements”). The Company has a history of conducting debt and equity financings, including the receipt of net proceeds of $162.1 million from a January 2021 underwritten public offering and net proceeds of $454.5 million under past Sales Agreements for the year ended December 31, 2020. However, sufficient funding may not be available in the future, or if available, may be on terms that significantly dilute or otherwise adversely affect the rights of existing stockholders. If adequate funds are not available, the Company may need to delay, reduce the scope of or put on hold one or more of its clinical and/or preclinical programs. The Company’s ability to continue its operations is dependent upon its ability to obtain additional capital in the future and achieve profitable operations. The Company expects to continue to rely on outside sources of financing to meet its capital needs and the Company may never achieve positive cash flow. These condensed consolidated financial statements do not include any adjustments to the specific amounts and classifications of assets and liabilities, which might be necessary should Inovio be unable to continue as a going concern. The Company's condensed consolidated financial statements as of and for the three and six months ended June 30, 2021 have been prepared on a going concern basis, which contemplates the realization of assets and the settlement of liabilities and commitments in the normal course of business for the foreseeable future. The Company has evaluated subsequent events after the balance sheet date through the date it issued these condensed consolidated financial statements. The Company is and, from time to time, may in the future be subject to various legal proceedings and claims arising in the ordinary course of business. The Company assesses contingencies to determine the degree of probability and range of possible loss for potential accrual in its consolidated financial statements. An estimated loss contingency is accrued in the consolidated financial statements if it is probable that a liability has been incurred and the amount of the loss can be reasonably estimated. Legal proceedings, including litigation, government investigations and enforcement actions, could result in material costs, occupy significant management resources and entail civil and criminal penalties, even if the Company ultimately prevails. Any of the foregoing consequences could result in serious harm to the Company’s business, results of operations and financial condition. Risks and Uncertainties The global pandemic resulting from COVID-19, caused by a novel strain of coronavirus, SARS-CoV-2, has caused national and global economic and financial market disruptions. The impact of this pandemic has been and will likely continue to be extensive in many aspects of society, which has resulted in and will continue to cause significant disruptions to the global economy, as well as businesses and capital markets around the world. The Company continues to closely monitor the impact of the COVID-19 pandemic on its employees, collaborators and service providers. The extent to which the pandemic will continue to impact the Company's business and operations will depend on future developments, including travel restrictions and social distancing in the United States and other countries, and the
Collaboration Agreements	Collaboration Agreements The Company assesses whether its collaboration agreements are subject to ASC Topic 808: Collaborative Arrangements (“Topic 808”) based on whether they involve joint operating activities and whether both parties have active participation in the arrangement and are exposed to significant risks and rewards. To the extent that the arrangement falls within the scope of Topic 808 and the Company concludes that its collaboration partner is not a customer, the Company presents such payments as a reduction of research and development expense. If payments from the collaboration partner to the Company represent consideration from a customer, then the Company accounts for those payments within the scope of Accounting Standards Update (“ASU”) 2014-09, Revenue from Contracts with Customers
Revenue Recognition	Revenue Recognition The Company recognizes revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which it expects to be entitled in exchange for those goods or services. To determine revenue recognition for contracts with customers, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the Company satisfies its performance obligations. At contract inception, the Company assesses the goods or services agreed upon within each contract and assess whether each good or service is distinct and determine those that are performance obligations. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. Collaborative Arrangements The Company enters into collaborative arrangements with partners that typically include payment of one or more of the following: (i) license fees; (ii) product supply services; (iii) milestone payments related to the achievement of developmental, regulatory, or commercial goals; and (iv) royalties on net sales of licensed products. Where a portion of non-refundable, upfront fees or other payments received are allocated to continuing performance obligations under the terms of a collaborative arrangement, they are recorded as deferred revenue and recognized as revenue when (or as) the underlying performance obligation is satisfied. As part of the accounting for these arrangements, the Company must develop estimates and assumptions that require judgment of management to determine the underlying stand-alone selling price for each performance obligation which determines how the transaction price is allocated among the performance obligation. The standalone selling price may include items such as forecasted revenues, development timelines, discount rates and probabilities of technical and regulatory success. The Company evaluates each performance obligation to determine if it can be satisfied at a point in time or over time. In addition, variable consideration must be evaluated to determine if it is constrained and, therefore, excluded from the transaction price. License Fees If a license to intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company will recognize revenues from non-refundable, upfront fees allocated to the license when the license is transferred to the licensee and the licensee is able to use and benefit from the license. For licenses that are bundled with other promises, the Company will utilize judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. Product Supply Services Arrangements that include a promise for future supply of drug product for either clinical development or commercial supply at the licensee’s discretion are generally considered as options. The Company will assess if these options provide a material right to the licensee and if so, they will be accounted for as separate performance obligations. The Company evaluates whether it is the principal or agent in the arrangement. The Company had determined that it is the principal in the current arrangements as the Company controls the product supply before it is transferred to the customer. Milestone Payments At the inception of each arrangement that includes milestone payments (variable consideration), the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company's or its collaboration partner’s control, such as regulatory approvals, are generally not considered probable of being achieved until those approvals are received. The transaction price is then allocated to each performance obligation on a relative stand-alone selling price basis, for which the Company recognizes revenue as or when the performance obligations under the contract are satisfied. At the end of each subsequent reporting period, the Company re-evaluates the probability of achieving such milestones and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect license, collaboration or other revenues and earnings in the period of adjustment. Royalties For arrangements that include sales-based royalties, including milestone payments based on the level of sales, and for which the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date, the Company has not recognized any royalty revenue resulting from any of its collaborative arrangements.
Grants	Grants The Company accounts for various grant agreements under the contributions guidance under Subtopic 958-605, Not-for-Profit Entities-Revenue Recognition
Leases	Leases For its long-term operating leases, the Company recognizes an operating lease right-of-use asset and an operating lease liability on its condensed consolidated balance sheets. The lease liability is determined as the present value of future lease payments using an estimated rate of interest that the Company would pay to borrow equivalent funds on a collateralized basis at the lease commencement date. The right-of-use asset is based on the liability adjusted for any prepaid or deferred rent. The Company determines the lease term at the commencement date by considering whether renewal options and termination options are reasonably assured of exercise. Fixed rent expense for the Company's operating leases is recognized on a straight-line basis over the term of the lease and is included in operating expenses on the condensed consolidated statements of operations. Variable lease payments including lease operating expenses are recorded as incurred.
Research and Development Expense	Research and Development Expenses The Company’s activities have largely consisted of research and development efforts related to developing electroporation delivery technologies, DNA vaccines, DNA immunotherapies and dMABs. Research and development expenses consist of expenses incurred in performing research and development activities including salaries and benefits, facilities and other overhead expenses, clinical trials, contract services and other outside expenses. Research and development expenses are charged to operations as they are incurred. These expenses result from the Company's independent research and development efforts as well as efforts associated with collaborations and licensing arrangements. The Company reviews and accrues clinical trial expense based on work performed, which relies on estimates of total costs incurred based on patient enrollment, completion of studies and other events. Accrued clinical trial costs are subject to revisions as trials progress. Revisions are charged to expense in the period in which the facts that give rise to the revision become known. Historically, revisions have not resulted in material changes to research and development expense; however, a modification in the protocol of a clinical trial or cancellation of a trial could result in a charge to the Company's results of operations.
Valuation of Intangible Assets and Goodwill	Valuation of Intangible Assets and Goodwill Intangible assets are amortized over their estimated useful lives ranging from two License costs are recorded based on the fair value of consideration paid and are amortized using the straight-line method over the shorter of the expected useful life of the underlying patents or the term of the related license agreement to the extent the license has an alternative future use. As of June 30, 2021 and December 31, 2020, the Company’s intangible assets resulting from the acquisition of Inovio AS and Bioject Medical Technologies, Inc. ("Bioject"), and additional intangibles including license costs, net of accumulated amortization, totaled $2.9 million and $3.1 million, respectively. The determination of the value of intangible assets requires management to make estimates and assumptions that affect the Company’s condensed consolidated financial statements. The Company assesses potential impairments to intangible assets when there is evidence that events or changes in circumstances indicate that the carrying amount of an asset may not be recovered. The Company’s judgments regarding the existence of impairment indicators and future cash flows related to intangible assets are based on operational performance of its acquired businesses, market conditions and other factors. If impairment is indicated, the Company will reduce the carrying value of the intangible asset to fair value. While current and historical operating and cash flow losses are potential indicators of impairment, the Company believes the future cash flows to be received from its intangible assets will exceed the intangible assets’ carrying value, and accordingly, the Company has not recognized any impairment losses through June 30, 2021. Goodwill represents the excess of acquisition cost over the fair value of the net assets of acquired businesses. Goodwill is reviewed for impairment at least annually at November 30, or more frequently if an event occurs indicating the potential for impairment. During its goodwill impairment review, the Company may assess qualitative factors to determine whether it is more likely than not that the fair value of its reporting unit is less than its carrying amount, including goodwill. The qualitative factors include, but are not limited to, macroeconomic conditions, industry and market considerations, and the overall financial performance of the Company. If, after assessing the totality of these qualitative factors, the Company determines that it is not likely that the fair value of its reporting unit is less than its carrying amount, then no additional assessment is deemed necessary. Otherwise, the Company will proceed to perform the impairment test in which the fair value of the reporting unit is compared with its carrying amount, and an impairment charge will be recorded for the amount by which the carrying amount exceeds the reporting unit's fair value, if any. The Company performed its annual assessment for goodwill impairment as of November 30, 2020, identifying no impairment.
Foreign Currency Translation	Foreign Currency Translation The functional and presentation currency of the Company is the U.S. dollar. Transactions denominated in a currency other than the functional currency are recorded on the initial recognition at the exchange rate at the date of the transaction. After initial recognition monetary assets and liabilities denominated in foreign currency are translated at the end of each reporting period into the functional currency at the exchange rate at that date. The cumulative translation adjustment is included in the accumulated other comprehensive income (loss) within the statement of stockholders' equity. Exchange differences are included in general and administrative expenses in the condensed consolidated statement of operations. Non- monetary assets and liabilities measured at cost are translated at the exchange rate at the date of the transaction.
Variable Interest Entities (VIE)	Variable Interest Entities (VIE) The Company evaluates its ownership, contractual and other interests in entities that are not wholly-owned to determine if these entities are VIEs, and, if so, whether the Company is the primary beneficiary of the VIE. In determining whether the Company is the primary beneficiary of a VIE and therefore required to consolidate the VIE, the Company applies a qualitative approach that determines whether it has both (1) the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance and (2) the obligation to absorb losses of, or the rights to receive benefits from, the VIE that could potentially be significant to that VIE. The Company will continuously perform this assessment, as changes to existing relationships or future transactions may result in the consolidation or deconsolidation of a VIE.
Equity Investments	Equity Investments Under ASC Topic 321, Investments - Equity Securities, the Company must measure equity investments (except those accounted for under the equity method, those that result in consolidation of the investee and certain other investments) at fair value and recognize any changes in fair value in the condensed consolidated statement of operations. The Company can elect a measurement alternative for equity investments that do not have readily determinable fair values and do not qualify for the practical expedient in ASC 820, Fair Value Measurement, to estimate fair value using the net asset value per share (or its
Recently Issued Accounting Standards	The recent accounting pronouncements below may have a significant effect on the Company's financial statements. Recent accounting pronouncements that are not anticipated to have an impact on or are unrelated to the Company's financial condition, results of operations, or related disclosures are not discussed. Accounting Standards Pending Adoption ASU No. 2020-06. In August 2020, the FASB issued ASU No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity (“ASU 2020-06”), which simplifies the guidance on an issuer’s accounting for convertible instruments and contracts in its own equity. The standard is effective for the Company beginning in the first quarter of 2022, with early adoption permitted in the first quarter of 2021. The Company did not elect to early adopt the standard and does not expect ASU 2020-06 to have a material impact to its condensed consolidated financial statements.

Short-term Investments (Tables)

Short-term Investments (Tables)	6 Months Ended
	Jun. 30, 2021
Investments, Debt and Equity Securities [Abstract]
Schedule of Summary of Investments	The following is a summary of available-for-sale securities as of June 30, 2021 and December 31, 2020: As of June 30, 2021 Contractual Cost Gross Unrealized Gross Unrealized Fair Market Value Mutual funds --- $ 207,475,699 $ 1,563,089 $ (579,056) $ 208,459,732 U.S. treasury securities Less than 1 170,203,940 10,943 (4,754) 170,210,129 Certificates of deposit Less than 1 2,972,816 25,684 — 2,998,500 U.S. agency mortgage-backed securities * 3,130,877 2,782 (49,638) 3,084,021 $ 383,783,332 $ 1,602,498 $ (633,448) $ 384,752,382 As of December 31, 2020 Contractual Cost Gross Unrealized Gross Unrealized Fair Market Value Mutual funds --- $ 153,177,675 $ 2,339,639 $ (644,140) $ 154,873,174 Certificates of deposit Less than 1 3,000,000 26,260 (10,000) 3,016,260 U.S. agency mortgage-backed securities * 3,062,256 — (36,755) 3,025,501 Total investments $ 159,239,931 $ 2,365,899 $ (690,895) $ 160,914,935 *No single maturity date.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2021
Fair Value Disclosures [Abstract]
Schedule of Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis	The following table presents the Company’s assets that were measured at fair value on a recurring basis, determined using the following inputs as of June 30, 2021: Fair Value Measurements at June 30, 2021 Total Quoted Prices Significant Significant Assets: Short-term investments Mutual funds $ 208,459,732 $ 208,459,732 $ — $ — U.S. treasury securities 170,210,129 170,210,129 — — Certificates of deposit 2,998,500 — 2,998,500 — U.S. agency mortgage-backed securities 3,084,021 — 3,084,021 — Total short-term investments 384,752,382 378,669,861 6,082,521 — Investment in affiliated entity 3,908,709 3,908,709 — — Total assets measured at fair value $ 388,661,091 $ 382,578,570 $ 6,082,521 $ — The following table presents the Company’s assets that were measured at fair value on a recurring basis, determined using the following inputs as of December 31, 2020: Fair Value Measurements at December 31, 2020 Total Quoted Prices Significant Significant Assets: Cash and cash equivalents U.S. treasury securities $ 59,996,800 $ 59,996,800 $ — $ — Short-term investments Mutual funds 154,873,174 154,873,174 — — Certificates of deposit 3,016,260 3,016,260 — U.S. agency mortgage-backed securities 3,025,501 — 3,025,501 — Total short-term investments 160,914,935 154,873,174 6,041,761 — Investment in affiliated entity 4,460,366 4,460,366 — — Total assets measured at fair value $ 225,372,101 $ 219,330,340 $ 6,041,761 $ —

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	6 Months Ended
	Jun. 30, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Summary of Intangible Assets by Major Asset Class	The following sets forth the goodwill and intangible assets by major asset class: June 30, 2021 December 31, 2020 Weighted Average Useful Gross Accumulated Net Book Gross Accumulated Net Book Indefinite lived: Goodwill $ 10,513,371 $ — $ 10,513,371 $ 10,513,371 $ — $ 10,513,371 Definite lived: Licenses 10 1,323,761 (1,291,226) 32,535 1,323,761 (1,276,852) 46,909 Bioject(a) 12 5,100,000 (2,608,889) 2,491,111 5,100,000 (2,468,889) 2,631,111 Other(b) 18 4,050,000 (3,693,750) 356,250 4,050,000 (3,581,250) 468,750 Total intangible assets 11 10,473,761 (7,593,865) 2,879,896 10,473,761 (7,326,991) 3,146,770 Total goodwill and intangible assets $ 20,987,132 $ (7,593,865) $ 13,393,267 $ 20,987,132 $ (7,326,991) $ 13,660,141 (a) Bioject intangible assets represent the estimated fair value of developed technology and intellectual property which were recorded from an asset acquisition.

Convertible Debt (Tables)

Convertible Debt (Tables)	6 Months Ended
	Jun. 30, 2021
Debt Disclosure [Abstract]
Schedule of Convertible Debt	The balance of the Notes at June 30, 2021 is as follows: Original principal amount $ 78,500,000 Principal amount converted into common shares (62,085,000) Unamortized debt discount on the liability component (1,963,908) Unamortized debt issuance cost (270,302) Accrued interest 355,658 Net carrying amount $ 14,536,448
Schedule of Maturities of Long-term Debt	As of June 30, 2021, future minimum payments due under the Notes, representing contractual amounts due, including interest based on the fixed rate of 6.5% per annum, are as follows: Remainder of 2021 $ 534,000 2022 1,067,000 2023 1,067,000 2024 16,948,000 Total $ 19,616,000

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2021
Stockholders' Equity Note [Abstract]
Schedule of Summary of Common and Preferred Stock Authorized, Issued and Outstanding	The following is a summary of the Company's authorized and issued common and preferred stock as of June 30, 2021 and December 31, 2020: Outstanding as of Authorized Issued June 30, 2021 December 31, 2020 Common Stock, par value $0.001 per share 600,000,000 210,146,880 210,146,880 186,851,493 Series C Preferred Stock, par value $0.001 per share 1,091 1,091 9 9

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	6 Months Ended
	Jun. 30, 2021
Earnings Per Share [Abstract]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The following table summarizes potential shares of common stock that were excluded from the diluted net loss per share calculation because of their anti-dilutive effect for the three and six months ended June 30, 2021 and 2020: Common Stock Equivalents 2021 2020 Options to purchase common stock 10,330,818 9,193,096 Service-based restricted stock units 2,516,102 2,868,665 Performance-based restricted stock units 663,353 — Convertible preferred stock 3,309 3,309 Convertible notes 3,049,980 14,585,653 August 2019 Bonds — 4,962,364 December 2019 Bonds — 1,009,450 Total 16,563,562 32,622,537

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2021
Share-based Payment Arrangement [Abstract]
Schedule of Weighted Average Assumptions	The weighted average assumptions used in the Black-Scholes model for option grants to employees and directors are presented below: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Risk-free interest rate 0.99% 0.40% 0.90% 0.67% Expected volatility 93% 80% 92% 77% Expected life in years 5.7 5.9 5.8 5.9 Dividend yield — — — —

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2021
Leases [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases	As of June 30, 2021, the maturities of the Company's operating lease liabilities were as follows: Remainder of 2021 $ 1,994,000 2022 4,045,000 2023 4,023,000 2024 3,001,000 2025 3,063,000 Thereafter 9,888,000 Total remaining lease payments 26,014,000 Less: present value adjustment (6,753,000) Total operating lease liabilities 19,261,000 Less: current portion (2,464,000) Long-term operating lease liabilities $ 16,797,000 Weighted-average remaining lease term 7.0 years Weighted-average discount rate 8.5%

Geneos Therapeutics, Inc. (Tabl

Geneos Therapeutics, Inc. (Tables)	6 Months Ended
	Jun. 30, 2021
Noncontrolling Interest [Abstract]
Schedule of Equity Method Investments	The following table shows the amounts related to the deconsolidation accounting: Working capital (excluding cash) $ (59,992) Note payable 171,620 Fixed assets, net of accumulated depreciation (16,340) Carrying value of noncontrolling interest 3,181,640 Fair value of investment in Geneos retained 3,618,998 Gain on deconsolidation of Geneos (4,121,075) Decrease in cash resulting from the deconsolidation of Geneos $ 2,774,851 The details of the Company’s 47% retained equity investment in Geneos is shown in the table below, with fair values calculated as of June 1, 2020, the date of deconsolidation. Geneos Share Class Shares Price per Share Fair Value Common 3,000,000 $ 0.273 $ 819,000 Preferred 2,113,206 $ 1.325 $ 2,799,998 Total 5,113,206 $ 3,618,998 Investment in Geneos upon deconsolidation $ 3,618,998 Investment in Geneos Series A-1 preferred stock 1,399,999 Share in net loss of Geneos from June 1, 2020 - December 31, 2020 (4,584,610) Share in net loss of Geneos for the three months ended March 31, 2021 (434,387) Investment in Geneos as of March 31, 2021 $ —
Schedule of Fair Value Measurement Inputs and Valuation Techniques	The assumptions used in the fair value calculation as of June 1, 2020 are presented below: Expected term (years) 2.92 Volatility 70% Risk-free interest rate 2.46% Geneos enterprise value $4,966,531

Basis of Presentation, Liquid_3

Basis of Presentation, Liquidity and Risks and Uncertainties (Details) - USD ($)	3 Months Ended			6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net loss	$ 82,139,958		$ 128,703,059	$ 136,542,089	$ 161,244,113
Working capital	490,700,000			490,700,000
Retained earnings (accumulated deficit)	1,042,738,901			1,042,738,901		$ 906,196,812
Cash, cash equivalents, and short-term investments	$ 443,700,000			443,700,000
Proceeds from issuance of stock				$ 162,105,030	$ 329,960,855
Common stock | Underwritten Public Offering
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Proceeds from issuance of stock		$ 162,100,000
Common stock | Sales Agreements
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Proceeds from issuance of stock		$ 454,500,000

Critical Accounting Policies (D

Critical Accounting Policies (Details) - USD ($)	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net	$ 2,879,896	$ 3,146,770
Minimum
Finite-Lived Intangible Assets [Line Items]
Useful life (in years)	2 years
Maximum
Finite-Lived Intangible Assets [Line Items]
Useful life (in years)	18 years

Revenue Recognition (Details)

Revenue Recognition (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Total revenues	$ 272,824	$ 267,187	$ 643,945	$ 1,594,461
Revenue recognized from deferred revenue	35,000		39,000
Plumbline Life Sciences
Disaggregation of Revenue [Line Items]
Total revenues	75,000	$ 64,000	125,000	$ 1,200,000
Other Counterparty
Disaggregation of Revenue [Line Items]
Total revenues	$ 198,000		$ 519,000

Short-term Investments - Narrat

Short-term Investments - Narrative (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2021USD ($)position	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)position	Jun. 30, 2020USD ($)
Investments, Debt and Equity Securities [Abstract]
Realized gain on investments	$ 358,000	$ 585,000	$ 358,000	$ 635,000
Realized loss on investments	194,000	686,000	204,000	1,200,000
Unrealized gain (loss) on available-for-sale equity securities	$ 136,493	$ 4,358,634	$ (711,465)	$ (691,458)
Number of securities in a gross unrealized loss position | position	22		22
Number of securities in a gross unrealized loss position for more than twelve months | position	4		4
Unrealized loss			$ 211,000

Short-term Investments - Summar

Short-term Investments - Summary of Available-for-sale Securities (Details) - USD ($)	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Debt Securities, Available-for-sale [Abstract]
Cost	$ 383,783,332		$ 159,239,931
Gross Unrealized Gains	1,602,498		2,365,899
Gross Unrealized Losses	(633,448)		(690,895)
Fair Market Value	384,752,382		160,914,935
Mutual funds
Debt Securities, Available-for-sale [Abstract]
Cost	207,475,699		153,177,675
Gross Unrealized Gains	1,563,089		2,339,639
Gross Unrealized Losses	(579,056)		(644,140)
Fair Market Value	$ 208,459,732		154,873,174
U.S. treasury securities
Debt Securities, Available-for-sale [Line Items]
Contractual maturity (less than)	1 year
Debt Securities, Available-for-sale [Abstract]
Cost	$ 170,203,940
Gross Unrealized Gains	10,943
Gross Unrealized Losses	(4,754)
Fair Market Value	$ 170,210,129
Certificates of deposit
Debt Securities, Available-for-sale [Line Items]
Contractual maturity (less than)	1 year	1 year
Debt Securities, Available-for-sale [Abstract]
Cost	$ 2,972,816		3,000,000
Gross Unrealized Gains	25,684		26,260
Gross Unrealized Losses	0		(10,000)
Fair Market Value	2,998,500		3,016,260
U.S. agency mortgage-backed securities
Debt Securities, Available-for-sale [Abstract]
Cost	3,130,877		3,062,256
Gross Unrealized Gains	2,782		0
Gross Unrealized Losses	(49,638)		(36,755)
Fair Market Value	$ 3,084,021		$ 3,025,501

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Measured at Fair Value (Details) - USD ($)	Jun. 30, 2021	Dec. 31, 2020
Assets:
Debt securities, available for sale	$ 384,752,382	$ 160,914,935
Mutual funds
Assets:
Debt securities, available for sale	208,459,732	154,873,174
U.S. treasury securities
Assets:
Debt securities, available for sale	170,210,129
Certificates of deposit
Assets:
Debt securities, available for sale	2,998,500	3,016,260
U.S. agency mortgage-backed securities
Assets:
Debt securities, available for sale	3,084,021	3,025,501
Fair Value, Measurements, Recurring
Assets:
Debt securities, available for sale	384,752,382	160,914,935
Investment in affiliated entity	3,908,709	4,460,366
Total assets measured at fair value	388,661,091	225,372,101
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1)
Assets:
Debt securities, available for sale	378,669,861	154,873,174
Investment in affiliated entity	3,908,709	4,460,366
Total assets measured at fair value	382,578,570	219,330,340
Fair Value, Measurements, Recurring | Significant Other Unobservable Inputs (Level 2)
Assets:
Debt securities, available for sale	6,082,521	6,041,761
Investment in affiliated entity	0	0
Total assets measured at fair value	6,082,521	6,041,761
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Debt securities, available for sale	0	0
Investment in affiliated entity	0	0
Total assets measured at fair value	0	0
Fair Value, Measurements, Recurring | Mutual funds
Assets:
Debt securities, available for sale	208,459,732	154,873,174
Fair Value, Measurements, Recurring | Mutual funds | Quoted Prices in Active Markets (Level 1)
Assets:
Debt securities, available for sale	208,459,732	154,873,174
Fair Value, Measurements, Recurring | Mutual funds | Significant Other Unobservable Inputs (Level 2)
Assets:
Debt securities, available for sale	0	0
Fair Value, Measurements, Recurring | Mutual funds | Significant Unobservable Inputs (Level 3)
Assets:
Debt securities, available for sale	0	0
Fair Value, Measurements, Recurring | U.S. treasury securities
Assets:
Cash and cash equivalents, fair value		59,996,800
Debt securities, available for sale	170,210,129
Fair Value, Measurements, Recurring | U.S. treasury securities | Quoted Prices in Active Markets (Level 1)
Assets:
Cash and cash equivalents, fair value		59,996,800
Debt securities, available for sale	170,210,129
Fair Value, Measurements, Recurring | U.S. treasury securities | Significant Other Unobservable Inputs (Level 2)
Assets:
Cash and cash equivalents, fair value		0
Debt securities, available for sale	0
Fair Value, Measurements, Recurring | U.S. treasury securities | Significant Unobservable Inputs (Level 3)
Assets:
Cash and cash equivalents, fair value		0
Debt securities, available for sale	0
Fair Value, Measurements, Recurring | Certificates of deposit
Assets:
Debt securities, available for sale	2,998,500	3,016,260
Fair Value, Measurements, Recurring | Certificates of deposit | Quoted Prices in Active Markets (Level 1)
Assets:
Debt securities, available for sale	0
Fair Value, Measurements, Recurring | Certificates of deposit | Significant Other Unobservable Inputs (Level 2)
Assets:
Debt securities, available for sale	2,998,500	3,016,260
Fair Value, Measurements, Recurring | Certificates of deposit | Significant Unobservable Inputs (Level 3)
Assets:
Debt securities, available for sale	0	0
Fair Value, Measurements, Recurring | U.S. agency mortgage-backed securities
Assets:
Debt securities, available for sale	3,084,021	3,025,501
Fair Value, Measurements, Recurring | U.S. agency mortgage-backed securities | Quoted Prices in Active Markets (Level 1)
Assets:
Debt securities, available for sale	0	0
Fair Value, Measurements, Recurring | U.S. agency mortgage-backed securities | Significant Other Unobservable Inputs (Level 2)
Assets:
Debt securities, available for sale	3,084,021	3,025,501
Fair Value, Measurements, Recurring | U.S. agency mortgage-backed securities | Significant Unobservable Inputs (Level 3)
Assets:
Debt securities, available for sale	$ 0	$ 0

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details)	Jun. 30, 2021shares
Common stock | Level 1
Marketable Securities and Fair Value Measurements (Textual) [Abstract]
Investment owned (in shares)	597,808

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Schedule Goodwill and Intangible Assets (Details) - USD ($)	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Indefinite lived:
Goodwill, gross	$ 10,513,371	$ 10,513,371
Goodwill, net book value	10,513,371	10,513,371
Definite lived:
Intangible assets, gross	10,473,761	10,473,761
Intangible assets, accumulated amortization	(7,593,865)	(7,326,991)
Intangible assets, net book value	2,879,896	3,146,770
Total goodwill and intangible assets, gross	20,987,132	20,987,132
Total goodwill and intangible assets, net book value	13,393,267	13,660,141
Licenses
Definite lived:
Intangible assets, gross	1,323,761	1,323,761
Intangible assets, accumulated amortization	(1,291,226)	(1,276,852)
Intangible assets, net book value	32,535	46,909
Bioject
Definite lived:
Intangible assets, gross	5,100,000	5,100,000
Intangible assets, accumulated amortization	(2,608,889)	(2,468,889)
Intangible assets, net book value	2,491,111	2,631,111
Other
Definite lived:
Intangible assets, gross	4,050,000	4,050,000
Intangible assets, accumulated amortization	(3,693,750)	(3,581,250)
Intangible assets, net book value	$ 356,250	$ 468,750
Weighted Average
Definite lived:
Useful life (in years)	11 years
Weighted Average | Licenses
Definite lived:
Useful life (in years)	10 years
Weighted Average | Bioject
Definite lived:
Useful life (in years)	12 years
Weighted Average | Other
Definite lived:
Useful life (in years)	18 years

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Aggregate amortization expense on intangible assets	$ 130,000	$ 137,000	$ 266,874	$ 273,540
Estimated aggregate amortization expense for remainder of 2021	254,000		254,000
Estimated aggregate amortization expense for 2022	493,000		493,000
Estimated aggregate amortization expense for 2023	276,000		276,000
Estimated aggregate amortization expense for 2024	253,000		253,000
Estimated aggregate amortization expense for 2025	253,000		253,000
Estimated aggregate amortization expense for 2026	$ 1,400,000		$ 1,400,000

Convertible Debt - Narrative (D

Convertible Debt - Narrative (Details)	Aug. 03, 2020$ / sharesshares	Dec. 26, 2019USD ($)$ / sharesshares	Aug. 01, 2019USD ($)	Mar. 01, 2019USD ($)day$ / shares	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)shares	Jun. 30, 2020USD ($)	Dec. 31, 2020USD ($)shares	Aug. 31, 2020USD ($)	Dec. 26, 2019KRW (₩)	Aug. 01, 2019KRW (₩)
Debt Instrument [Line Items]
Non-cash interest expense					$ 466,726	$ 2,846,641	$ 979,760	$ 5,650,396
Change in fair value of derivative liability					0	(97,755,000)	0	(110,976,977)
Convertible senior notes
Debt Instrument [Line Items]
Original principal amount					78,500,000		78,500,000
Unamortized debt issuance cost					270,302		270,302
Debt instrument, unamortized discount					$ 1,963,908		$ 1,963,908
August 2019 Bonds | Common stock
Debt Instrument [Line Items]
Debt conversion, converted instrument, shares issued (in shares) | shares									4,692,364
Convertible Debt | Convertible senior notes
Debt Instrument [Line Items]
Original principal amount				$ 78,500,000
Stated interest rate				6.50%	6.50%		6.50%
Proceeds from issuance of debt				$ 75,700,000
Debt instrument, convertible, conversion ratio				0.1858045
Debt instrument, convertible conversion price (in dollars per share) | $ / shares				$ 5.38
Debt instrument, convertible, threshold percentage of stock price trigger				130.00%
Debt instrument, convertible, threshold trading days | day				20
Debt instrument, convertible, threshold consecutive trading days | day				30
Debt instrument, redemption price percentage				100.00%
Carrying value				$ 62,200,000					$ 52,500,000
Unamortized debt issuance cost				2,800,000
Debt instrument, unamortized discount				$ 18,600,000
Debt instrument, effective interest rate					13.10%		13.10%
Debt conversion, converted instrument principal amount									$ 62,100,000
Debt conversion, converted instrument, shares issued (in shares) | shares									11,535,660
Fair value of date conversion									$ 43,700,000
Gain on extinguishment of debt									8,800,000
Non-cash interest expense					$ 467,000	2,100,000	$ 930,000	4,200,000
Interest expense, contractual interest					$ 267,000	1,300,000	$ 533,000	2,600,000
Convertible Debt | August 2019 Bonds
Debt Instrument [Line Items]
Original principal amount			$ 15,000,000									₩ 18,000,000,000
Stated interest rate			1.00%									1.00%
Proceeds from issuance of debt			$ 14,500,000
Debt instrument, convertible, conversion ratio	0.0002756873
Debt instrument, convertible conversion price (in dollars per share) | $ / shares	$ 3.14
Carrying value			7,100,000
Debt instrument, unamortized discount			$ 7,300,000
Debt conversion, converted instrument, shares issued (in shares) | shares	4,962,364
Gain on extinguishment of debt									8,200,000
Non-cash interest expense						672,000		1,300,000
Interest expense, contractual interest						37,000		75,000
Fair value of derivative liability										$ 84,500,000
Change in fair value of derivative liability									$ 75,700,000
Convertible Debt | August 2019 Bonds | Initial Conversion Price
Debt Instrument [Line Items]
Debt instrument, convertible, conversion ratio	0.0002110595
Debt instrument, convertible conversion price (in dollars per share) | $ / shares	$ 4
Convertible Debt | December 2019 Bonds
Debt Instrument [Line Items]
Original principal amount		$ 4,100,000									₩ 4,700,000,000
Stated interest rate		1.00%									1.00%
Proceeds from issuance of debt		$ 4,000,000
Debt instrument, effective interest rate					6.20%		6.20%
Debt conversion, converted instrument, shares issued (in shares) | shares		1,009,450					1,009,450
Non-cash interest expense						60,000	$ 50,000	122,000
Interest expense, contractual interest						$ 10,000	9,000	$ 20,000
Conversion of carrying value							$ 4,400,000
Convertible Debt | December 2019 Bonds | Initial Conversion Price
Debt Instrument [Line Items]
Debt instrument, convertible, conversion ratio		0.0002147766
Debt instrument, convertible conversion price (in dollars per share) | $ / shares		$ 4

Convertible Debt - Balance of C

Convertible Debt - Balance of Convertible Bonds and Notes (Details) - Convertible senior notes	Jun. 30, 2021USD ($)
Debt Instrument [Line Items]
Original principal amount	$ 78,500,000
Principal amount converted into common shares	(62,085,000)
Unamortized debt discount on the liability component	(1,963,908)
Unamortized debt issuance cost	(270,302)
Accrued interest	355,658
Net carrying amount	$ 14,536,448

Convertible Debt - Schedule of

Convertible Debt - Schedule of Maturities (Details) - Convertible senior notes - USD ($)	Jun. 30, 2021	Mar. 01, 2019
Debt Instrument [Line Items]
Net carrying amount	$ 14,536,448
Convertible Debt
Debt Instrument [Line Items]
Remainder of 2021	534,000
2022	1,067,000
2023	1,067,000
2024	16,948,000
Net carrying amount	$ 19,616,000
Stated interest rate	6.50%	6.50%

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Authorized and Issued Common and Preferred Stock (Details) - $ / shares	Jun. 30, 2021	Dec. 31, 2020
Summary of common and preferred stock authorized, issued and outstanding
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares, authorized (in shares)	600,000,000
Common stock, shares, issued (in shares)	210,146,880
Common stock, shares, outstanding (in shares)	210,146,880	186,851,493
Series C Preferred Stock
Summary of common and preferred stock authorized, issued and outstanding
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	1,091
Preferred stock, shares issued (in shares)	1,091
Preferred stock, shares outstanding (in shares)	9	9

Stockholders' Equity - Narrativ

Stockholders' Equity - Narrative (Details) - USD ($)	Jan. 25, 2021	Jun. 30, 2020	May 12, 2020	May 31, 2018	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Jan. 01, 2021	May 13, 2016
Class of Stock [Line Items]
Underwritten public offering, common stock (in shares)	20,355,000
Sale of stock, price per share (in dollars per share)	$ 8.50
Commissions and other estimated offering expenses	$ 162,100,000
2016 Incentive Plan
Class of Stock [Line Items]
Number of shares authorized (in shares)										20,000,000
Number of potential shares authorized for issuance under share based compensation plan (in shares)										2,000,000
Increase in number of shares authorized (in shares)									2,000,000
Number of shares available for grant (in shares)						4,998,253
Number of shares of unvested restricted stock units and options outstanding (in shares)						2,516,102
Common stock, other shares, outstanding (in shares)						7,814,677
Award vesting period (in years)						3 years
Maximum contractual term (in years)						10 years
2007 Incentive Plan
Class of Stock [Line Items]
Common stock, other shares, outstanding (in shares)						2,516,141
Award vesting period (in years)						3 years
Maximum contractual term (in years)						10 years
Series C Preferred Stock
Class of Stock [Line Items]
Conversion of stock, shares converted (in shares)		14
Common stock
Class of Stock [Line Items]
Conversion of stock, shares issued (in shares)		5,147
Common stock | Prior Sales Agreement
Class of Stock [Line Items]
Maximum authorized amount				$ 100,000,000			$ 250,000,000
Remaining authorized amount					$ 0
Aggregate number of shares issued (in shares)					43,148,952
Stock sale agreement weighted average price per share					$ 4.92
Aggregate proceeds					$ 208,200,000
Common stock | New Sales Agreement
Class of Stock [Line Items]
Maximum authorized amount			$ 250,000,000
Remaining authorized amount								$ 0
Aggregate number of shares issued (in shares)								22,919,934
Stock sale agreement weighted average price per share								$ 10.91
Aggregate proceeds								$ 246,200,000

Net Loss Per Share - Schedule o

Net Loss Per Share - Schedule of Anti-Dilutive Securities (Details) - shares	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded (in shares)	16,563,562	32,622,537
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded (in shares)	10,330,818	9,193,096
Service-based restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded (in shares)	2,516,102	2,868,665
Performance-based restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded (in shares)	663,353	0
Convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded (in shares)	3,309	3,309
Convertible senior notes | Convertible notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded (in shares)	3,049,980	14,585,653
August 2019 Bonds | Convertible notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded (in shares)	0	4,962,364
December 2019 Bonds | Convertible notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded (in shares)	0	1,009,450

Stock-Based Compensation (Detai

Stock-Based Compensation (Details) - USD ($)	Aug. 28, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation				$ 15,242,305	$ 7,663,988
Total unrecognized compensation cost related to unvested stock options		$ 19,800,000		$ 19,800,000
Period over which total unrecognized compensation cost related to unvested stock options will be recognized (in years)				2 years 3 months 18 days
Weighted average grant date fair value (in dollars per share)		$ 5.25	$ 9.52	$ 7.91	$ 6.19
2016 Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)				3 years
Research and Development Expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share-based compensation expense		$ 2,700,000	$ 1,800,000	$ 7,900,000	$ 4,100,000
General and Administrative Expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share-based compensation expense		2,600,000	1,600,000	6,600,000	3,000,000
Employees and Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation		5,300,000	3,400,000	14,500,000	7,100,000
Non Employee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation		$ 308,000	$ 224,000	$ 737,000	$ 607,000
Stock Options | Employees and Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate		0.99%	0.40%	0.90%	0.67%
Expected volatility		93.00%	80.00%	92.00%	77.00%
Expected life in years		5 years 8 months 12 days	5 years 10 months 24 days	5 years 9 months 18 days	5 years 10 months 24 days
Dividend yield		0.00%	0.00%	0.00%	0.00%
Performance-based restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost related to unvested stock options		$ 16,800,000		$ 16,800,000
Period over which total unrecognized compensation cost related to unvested stock options will be recognized (in years)				2 years 1 month 6 days
Weighted average grant date fair value, restricted stock units (in dollars per share)		$ 6.81	$ 14.50	$ 10.64	$ 9.12
Performance-based restricted stock units | 2016 Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value, restricted stock units (in dollars per share)	$ 12.06
Granted (in shares)	663,353
Grant date fair value	$ 8,000,000
Performance-based restricted stock units | 2016 Incentive Plan | Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	50.00%
Performance-based restricted stock units | 2016 Incentive Plan | Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	50.00%
Award vesting period (in years)	1 year

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($)	1 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended
	Nov. 30, 2016	Mar. 31, 2016	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Related-Party Transactions (Textual) [Abstract]
Revenue from related parties			$ 272,824	$ 267,187	$ 643,945	$ 1,594,461
Director
Related-Party Transactions (Textual) [Abstract]
Accounts receivable			617,000		617,000		$ 425,000
Expenses to reimburse		$ 3,100,000
Term		5 years
Awarded amount	$ 6,100,000
Contra-research and development expense			381,000	73,000	610,000	691,000
Operating expenses related to affiliated entity			1,200,000	408,000	1,600,000	770,000
Accounts payable/accrued liabilities			1,800,000		1,800,000		643,000
Prepaid balance			303,000		303,000
Deferred grant funding, from affiliate			69,000		69,000
The Wistar Institute
Related-Party Transactions (Textual) [Abstract]
Awarded amount							10,700,000
Awarded option amount							6,000,000
Plumbline Life Sciences
Related-Party Transactions (Textual) [Abstract]
Revenue from related parties			75,000	$ 64,000	125,000	$ 1,200,000
Accounts receivable			$ 99,000		$ 99,000		$ 67,000
Plumbline Life Sciences | Available-for-sale Securities
Related-Party Transactions (Textual) [Abstract]
Investment owned (in shares)			597,808		597,808
Ownership percentage			19.70%		19.70%

Leases - Narrative (Details)

Leases - Narrative (Details) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)	Dec. 31, 2019ft²agreement	Jun. 30, 2021USD ($)ft²	Jun. 30, 2020USD ($)
Lessee, Lease, Description [Line Items]
Lease cost | $	$ 827	$ 814		$ 1,700	$ 1,700
Number of agreements | agreement			2
Minimum
Lessee, Lease, Description [Line Items]
Operating lease, remaining lease term	2 years 4 months 24 days			2 years 4 months 24 days
Maximum
Lessee, Lease, Description [Line Items]
Operating lease, remaining lease term	8 years 6 months			8 years 6 months
San Diego, California
Lessee, Lease, Description [Line Items]
Area leased (in square feet)				82,200
Plymouth Meeting, Pennsylvania
Lessee, Lease, Description [Line Items]
Area leased (in square feet)			13,500	57,360

Leases - Summary of Future Mini

Leases - Summary of Future Minimum Lease Payments (Details) - USD ($)	Jun. 30, 2021	Dec. 31, 2020
Leases [Abstract]
Remainder of 2021	$ 1,994,000
2022	4,045,000
2023	4,023,000
2024	3,001,000
2025	3,063,000
Thereafter	9,888,000
Total remaining lease payments	26,014,000
Less: present value adjustment	(6,753,000)
Total operating lease liabilities	19,261,000
Less: current portion	(2,463,878)	$ (2,329,394)
Long-term operating lease liabilities	$ 16,797,476	$ 18,063,515
Weighted-average remaining lease term	7 years
Weighted-average discount rate	8.50%

Collaborative Agreements (Detai

Collaborative Agreements (Details) - USD ($)	Dec. 31, 2017	Dec. 29, 2017	Jun. 30, 2020	Apr. 30, 2020	Mar. 31, 2020	Jan. 31, 2020	Aug. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Oct. 31, 2018	Apr. 30, 2018	Mar. 31, 2018	Sep. 30, 2015	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Jun. 30, 2018	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenues														$ 272,824		$ 267,187		$ 643,945	$ 1,594,461
Grant funding liability														6,859,155				6,859,155		$ 7,474,310
Advaccine | Customer Concentration Risk
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable														0				0		7,100,000
Revenue under collaborative research and development arrangements
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenues														82,923		74,102		122,538	145,602
Advaccine | Collaborative Arrangement, Product
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payment received																		3,000,000
Additional revenue to be achieved																		206,000,000
Collaboration Agreement, Payment Earned																		$ 2,000,000
Royalty period																		10 years
Revenues															$ 5,000,000
Annual maintenance fee																		$ 1,500,000
Annual maintenance period																		5 years
Advaccine | Collaborative Arrangement, Product | Revenue under collaborative research and development arrangements
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenues															$ 5,000,000			$ 0
ApolloBio | Collaborative Arrangement, Product
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payment received												$ 23,000,000					$ 23,000,000	23,000,000
Additional revenue to be achieved																		$ 20,000,000
Royalty period																		10 years
Period from effective date for termination																		1 year
Territory expansion option period		3 years
Proceeds received in upfront payment												19,400,000
Advisory fees												960,000
Number of days written notice before termination																		90 days
ApolloBio | Collaborative Arrangement, Product | Foreign Tax Authority
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Foreign corporate income taxes reducing upfront payment												2,200,000
Foreign non-corporate income taxes reducing upfront payment												$ 1,400,000
AstraZeneca
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenues								$ 2,000,000	$ 2,000,000
AstraZeneca | Collaborative Arrangement, Product
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payment received	$ 27,500,000												$ 27,500,000
Anticipated development and regulatory event based payment receivable milestones																		$ 125,000,000
Anticipated commercial event based payment receivable milestones																		115,000,000
Coalition for Epidemic Preparedness Innovations | Collaborative Arrangement, Product
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaborative agreement, funding to be received				$ 6,900,000
Coalition for Epidemic Preparedness Innovations | Collaborative Arrangement, Product | Lassa Fever and MERS Vaccine
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaborative agreement, funding to be received											$ 56,000,000
Collaborative agreement, period to receive funding for research and development											5 years
Funding received for research and development														2,100,000		1,800,000		4,400,000	2,900,000
Grant funding liability														316,000				316,000
Coalition for Epidemic Preparedness Innovations | Collaborative Arrangement, Product | SARS-CoV-2/COVID-19 Vaccine
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaborative agreement, funding to be received						$ 9,000,000
Funding received for research and development														1,100,000		5,800,000		3,500,000	8,100,000
Grant funding liability														2,900,000				2,900,000
Coalition for Epidemic Preparedness Innovations | Collaborative Arrangement, Product | CELLECTRA 3PSP Proprietary Smart Device
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaborative agreement, funding to be received				5,000,000
Coalition for Epidemic Preparedness Innovations | Collaborative Arrangement, Product | INO-4800
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaborative agreement, funding to be received				$ 1,300,000
Bill and Melinda Gates Foundation | Collaborative Arrangement, Product | CELLECTRA 3PSP Proprietary Smart Device
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Funding received for research and development					$ 5,000,000									0		850,000		893,000	913,000
Bill and Melinda Gates Foundation | Collaborative Arrangement, Product | DNA-Encoded Monoclonal Antibody Technology
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Funding received for research and development							$ 1,100,000			$ 2,200,000						36,000			170,000
Grant funding liability														575,000				575,000
Department of Defence | Collaborative Arrangement, Product
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contra-research and development expense														13,400,000		$ 0		21,200,000	$ 0
Accounts receivable														12,900,000				12,900,000		$ 11,400,000
Deferred grant funding, from affiliate														$ 3,000,000				$ 3,000,000
Department of Defence | Collaborative Arrangement, Product | CELLECTRA 3PSP Proprietary Smart Device
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Funding received for research and development			$ 54,500,000
Department of Defence | Collaborative Arrangement, Product | CELLECTRA 2000 Device
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Purchase price, procurement contract			$ 16,600,000

Geneos Therapeutics, Inc. - Nar

Geneos Therapeutics, Inc. - Narrative (Details) - USD ($)	Jun. 01, 2020	Nov. 30, 2020	Feb. 28, 2019	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Feb. 28, 2021	Mar. 31, 2020	Jan. 31, 2020
Noncontrolling Interest [Line Items]
Gain on deconsolidation of investment				$ 0		$ 4,121,075	$ 0	$ 4,121,075
Share of net loss in Geneos				0		$ 901,757	434,387	$ 901,757
Investment in equity method investments				$ 0			$ 0		$ 434,387
Series A One Preferred Stock
Noncontrolling Interest [Line Items]
Investment in equity method investments	$ 1,399,999
Geneos Therapeutics, Inc.
Noncontrolling Interest [Line Items]
Noncontrolling interest, ownership percentage by parent		36.00%	61.00%							35.00%	52.00%
Ownership percentage				47.00%		47.00%	47.00%	47.00%
Geneos Therapeutics, Inc.
Noncontrolling Interest [Line Items]
Payments to acquire additional interest in subsidiaries		$ 1,400,000	$ 1,200,000
Stock purchase agreement, commitment of additional investment						$ 800,000		$ 800,000				$ 800,000
Gain on deconsolidation of investment	4,121,075
Deconsolidation gain, remeasurement of retained noncontrolling investment to fair value	2,400,000
Loss from equity method investment, recorded and allocated to investment					$ (1,500,000)				(4,600,000)
Share of net loss in Geneos					434,387				4,584,610
Investment in equity method investments	3,618,998			$ 0	0		$ 0
Geneos Therapeutics, Inc. | Common stock
Noncontrolling Interest [Line Items]
Investment in equity method investments	819,000				0
Geneos Therapeutics, Inc. | Preferred stock
Noncontrolling Interest [Line Items]
Share of net loss in Geneos									4,200,000
Investment in equity method investments	$ 2,799,998				$ 0
Geneos Therapeutics, Inc. | Series A One Preferred Stock
Noncontrolling Interest [Line Items]
Share of net loss in Geneos									$ 819,000

Geneos Therapeutics, Inc. - Dec

Geneos Therapeutics, Inc. - Deconsolidation Accounting (Details) - USD ($)	Jun. 01, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Noncontrolling Interest [Line Items]
Fixed assets, net of accumulated depreciation		$ (18,111,288)		$ (18,111,288)		$ (11,348,144)
Gain on deconsolidation of Geneos		$ 0	$ (4,121,075)	0	$ (4,121,075)
Decrease in cash resulting from the deconsolidation of Geneos				$ 0	$ 2,774,851
Geneos Therapeutics, Inc.
Noncontrolling Interest [Line Items]
Working capital (excluding cash)	$ (59,992)
Note payable	171,620
Fixed assets, net of accumulated depreciation	(16,340)
Carrying value of noncontrolling interest	3,181,640
Fair value of investment in Geneos retained	3,618,998
Gain on deconsolidation of Geneos	(4,121,075)
Decrease in cash resulting from the deconsolidation of Geneos	$ 2,774,851

Geneos Therapeutics, Inc. - Inv

Geneos Therapeutics, Inc. - Investment In Geneos (Details) - USD ($)	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Jun. 01, 2020
Noncontrolling Interest [Line Items]
Fair Value	$ 0		$ 434,387
Geneos Therapeutics, Inc.
Noncontrolling Interest [Line Items]
Shares (in shares)				5,113,206
Fair Value	$ 0	$ 0		$ 3,618,998
Common stock | Geneos Therapeutics, Inc.
Noncontrolling Interest [Line Items]
Shares (in shares)				3,000,000
Price per Share (in dollars per share)				$ 0.273
Fair Value		0		$ 819,000
Preferred stock | Geneos Therapeutics, Inc.
Noncontrolling Interest [Line Items]
Shares (in shares)				2,113,206
Price per Share (in dollars per share)				$ 1.325
Fair Value		$ 0		$ 2,799,998

Geneos Therapeutics, Inc. - Fai

Geneos Therapeutics, Inc. - Fair Value Assumptions (Details) - Geneos Therapeutics, Inc.	Jun. 01, 2020USD ($)
Noncontrolling Interest [Line Items]
Geneos enterprise value	$ 4,966,531,000
Expected term (years)
Noncontrolling Interest [Line Items]
Equity method investment, measurement input, expected term	2 years 11 months 1 day
Volatility
Noncontrolling Interest [Line Items]
Equity method investment, measurement input	0.70
Risk-free interest rate
Noncontrolling Interest [Line Items]
Equity method investment, measurement input	0.0246

Geneos Therapeutics, Inc. - Pre

Geneos Therapeutics, Inc. - Preferred stock Investment (Details) - USD ($)	3 Months Ended			6 Months Ended		7 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Investment in Geneos upon deconsolidation		$ 434,387		$ 434,387
Share in net loss of Geneos	$ 0		$ (901,757)	(434,387)	$ (901,757)
Investment in Geneos as of March 31, 2021	0			0		$ 434,387
Geneos Therapeutics, Inc.
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Investment in Geneos upon deconsolidation	0
Share in net loss of Geneos		(434,387)				(4,584,610)
Investment in Geneos as of March 31, 2021	$ 0	$ 0		$ 0
Geneos Therapeutics, Inc. | Series A One Preferred Stock
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Share in net loss of Geneos						$ (819,000)