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Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2020	Aug. 07, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Trading Symbol	ALT
Entity Registrant Name	ALTIMMUNE, INC.
Entity Central Index Key	0001326190
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Common Stock, Shares Outstanding		32,904,333
Entity File Number	001-32587
Entity Tax Identification Number	20-2726770
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	910 Clopper Road
Entity Address, Address Line Two	Suite 201S
Entity Address, City or Town	Gaithersburg
Entity Address, State or Province	MD
Entity Address, Postal Zip Code	20878
City Area Code	(240)
Local Phone Number	654-1450
Title of 12(b) Security	Common stock, par value $0.0001 per share
Security Exchange Name	NASDAQ
Document Quarterly Report	true
Document Transition Report	false

Consolidated Balance Sheets - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 64,741,921	$ 8,962,686
Restricted cash	34,174	34,174
Total cash, cash equivalents and restricted cash	64,776,095	8,996,860
Short-term investments	15,484,402	28,277,386
Accounts receivable	1,182,099	1,021,179
Tax refund receivable	5,506,946	629,096
Prepaid expenses and other current assets	1,020,876	470,228
Total current assets	87,970,418	39,394,749
Property and equipment, net	1,024,640	1,104,208
Right of use asset	662,074	698,321
Intangible assets, net	12,785,655	12,732,195
Other assets	100,980	128,547
Total assets	102,543,767	54,058,020
Current liabilities:
Accounts payable	195,217	18,232
Accrued expenses and other current liabilities	4,089,749	3,904,767
Notes payable	632,000
Total current liabilities	4,916,966	3,922,999
Contingent consideration	16,390,000	2,750,000
Other long-term liabilities	1,715,024	1,864,875
Total liabilities	23,021,990	8,537,874
Commitments and contingencies (Note 14)
Stockholders’ equity:
Common stock, $0.0001 par value; 200,000,000 shares authorized; 26,553,957 and 15,312,381 shares issued; 26,553,886 and 15,312,167 shares outstanding at June 30, 2020 and December 31, 2019, respectively	2,635	1,508
Additional paid-in capital	242,579,532	187,914,916
Accumulated deficit	(158,028,687)	(137,376,122)
Accumulated other comprehensive loss, net	(5,031,703)	(5,020,156)
Total stockholders’ equity	79,521,777	45,520,146
Total liabilities and stockholders’ equity	$ 102,543,767	$ 54,058,020

Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Common stock, par or stated value per share	$ 0.0001	$ 0.0001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	26,553,957	15,312,381
Common stock, shares outstanding	26,553,886	15,312,167

Consolidated Statements of Operations and Comprehensive Loss - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Statement [Abstract]
Revenues	$ 721,636	$ 1,626,029	$ 2,934,330	$ 4,581,622
Operating expenses:
Research and development	16,594,250	2,945,096	23,781,781	6,162,768
General and administrative	2,545,356	2,231,817	4,877,273	4,298,299
Total operating expenses	19,139,606	5,176,913	28,659,054	10,461,067
Loss from operations	(18,417,970)	(3,550,884)	(25,724,724)	(5,879,445)
Other (expense) income:
Changes in fair value of warrant liability		(46,000)		(46,000)
Interest expense	(3,308)	(748)	(5,193)	(1,488)
Interest income	81,458	239,964	233,027	425,211
Other (expense) income, net	(5,878)	(29,220)	19,664	17,528
Total other (expense) income, net	72,272	163,996	247,498	395,251
Net loss before income tax benefit	(18,345,698)	(3,386,888)	(25,477,226)	(5,484,194)
Income tax benefit	1,578,782		4,824,661
Net loss	(16,766,916)	(3,386,888)	(20,652,565)	(5,484,194)
Other comprehensive loss – unrealized gain (loss) on investments	20,888		(11,547)
Comprehensive loss	(16,746,028)	(3,386,888)	(20,664,112)	(5,484,194)
Net loss	(16,766,916)	(3,386,888)	(20,652,565)	(5,484,194)
Deemed dividends				(452,925)
Net loss attributed to common stockholders	$ (16,766,916)	$ (3,386,888)	$ (20,652,565)	$ (5,937,119)
Net loss per share attributed to common stockholders, basic and diluted	$ (0.94)	$ (0.26)	$ (1.25)	$ (0.52)
Weighted-average common shares outstanding, basic and diluted	17,886,853	13,127,773	16,498,719	11,318,819

Consolidated Statements of changes in Stockholders' Equity - USD ($)	Total	Market Offering [Member]	Registered Direct Offering [Member]	Common Stock [Member]	Common Stock [Member] Market Offering [Member]	Common Stock [Member] Registered Direct Offering [Member]	Additional Paid-In Capital [Member]	Additional Paid-In Capital [Member] Market Offering [Member]	Additional Paid-In Capital [Member] Registered Direct Offering [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]
Beginning Balance at Dec. 31, 2018	$ 48,312,566			$ 876			$ 170,207,844			$ (116,855,991)	$ (5,040,163)
Beginning Balance (in shares) at Dec. 31, 2018				9,078,239
Stock-based compensation	407,714						407,714
Vesting of restricted stock awards including withholding, net	28						28
Vesting of restricted stock awards including withholding, net (in shares)				71
Issuance of common stock, net of offering costs			$ 12,668,784			$ 436			$ 12,668,348
Issuance of common stock, net of offering costs (in shares)						4,361,370
Issuance of common stock upon exercise of warrants	30,324			$ 1			30,323
Issuance of common stock upon exercise of warrants (in shares)				11,000
Net loss	(2,097,306)									(2,097,306)
Ending Balance at Mar. 31, 2019	59,322,110			$ 1,313			183,314,257			(118,953,297)	(5,040,163)
Ending Balance (in shares) at Mar. 31, 2019				13,450,680
Beginning Balance at Dec. 31, 2018	48,312,566			$ 876			170,207,844			(116,855,991)	(5,040,163)
Beginning Balance (in shares) at Dec. 31, 2018				9,078,239
Net loss	(5,484,194)
Ending Balance at Jun. 30, 2019	56,225,022			$ 1,313			183,604,057			(122,340,185)	(5,040,163)
Ending Balance (in shares) at Jun. 30, 2019				13,450,751
Beginning Balance at Mar. 31, 2019	59,322,110			$ 1,313			183,314,257			(118,953,297)	(5,040,163)
Beginning Balance (in shares) at Mar. 31, 2019				13,450,680
Stock-based compensation and vesting of restricted stock	289,800						289,800
Stock based compensation and vesting of restricted stock (in shares)				71
Net loss	(3,386,888)									(3,386,888)
Ending Balance at Jun. 30, 2019	56,225,022			$ 1,313			183,604,057			(122,340,185)	(5,040,163)
Ending Balance (in shares) at Jun. 30, 2019				13,450,751
Beginning Balance at Dec. 31, 2019	45,520,146			$ 1,508			187,914,916			(137,376,122)	(5,020,156)
Beginning Balance (in shares) at Dec. 31, 2019				15,312,167
Stock-based compensation	214,921						214,921
Vesting of restricted stock awards including withholding, net	(17,079)			$ 1			(17,080)
Vesting of restricted stock awards including withholding, net (in shares)				(5,974)
Issuance of common stock from Employee Stock Purchase Plan	56,739			$ 3			56,736
Issuance of common stock from Employee Stock Purchase Plan (in shares)				38,809
Issuance of common stock upon exercise of warrants	39,974			$ 2			39,972
Issuance of common stock upon exercise of warrants (in shares)				14,500
Unrealized (loss) gain on short-term investments	(32,435)										(32,435)
Net loss	(3,885,649)									(3,885,649)
Ending Balance at Mar. 31, 2020	41,896,617			$ 1,514			188,209,465			(141,261,771)	(5,052,591)
Ending Balance (in shares) at Mar. 31, 2020				15,359,502
Beginning Balance at Dec. 31, 2019	45,520,146			$ 1,508			187,914,916			(137,376,122)	(5,020,156)
Beginning Balance (in shares) at Dec. 31, 2019				15,312,167
Unrealized (loss) gain on short-term investments	(11,547)
Net loss	(20,652,565)
Ending Balance at Jun. 30, 2020	79,521,777			$ 2,635			242,579,532			(158,028,687)	(5,031,703)
Ending Balance (in shares) at Jun. 30, 2020				26,553,886
Beginning Balance at Mar. 31, 2020	41,896,617			$ 1,514			188,209,465			(141,261,771)	(5,052,591)
Beginning Balance (in shares) at Mar. 31, 2020				15,359,502
Stock-based compensation	330,510						330,510
Exercise of stock options	36,175			$ 1			36,174
Exercises of stock options (in shares)				13,935
Vesting of restricted stock awards including withholding, net	(46,389)			$ 1			(46,390)
Vesting of restricted stock awards including withholding, net (in shares)				(5,974)
Issuance of common stock, net of offering costs		$ 22,780,729			$ 297			$ 22,780,432
Issuance of common stock, net of offering costs (in shares)					2,965,144
Issuance of common stock upon exercise of warrants	31,270,163			$ 822			31,269,341
Issuance of common stock upon exercise of warrants (in shares)				8,221,279
Unrealized (loss) gain on short-term investments	20,888										20,888
Net loss	(16,766,916)									(16,766,916)
Ending Balance at Jun. 30, 2020	$ 79,521,777			$ 2,635			$ 242,579,532			$ (158,028,687)	$ (5,031,703)
Ending Balance (in shares) at Jun. 30, 2020				26,553,886

Consolidated Statements of Cash Flows - USD ($)	6 Months Ended
Consolidated Statements of Cash Flows - USD ($)	Jun. 30, 2020	Jun. 30, 2019
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (20,652,565)	$ (5,484,194)
Adjustments to reconcile net loss to net cash used in operating activities:
Change in fair value of contingent consideration	13,640,000
Stock-based compensation expense	545,431	697,486
Depreciation	120,169	121,899
Amortization	25,876	107,580
Unrealized losses (gains) on foreign currency exchange	(18,851)	(24,943)
Changes in fair value of warrant liability		46,000
Changes in operating assets and liabilities:
Accounts receivable	(160,920)	832,098
Prepaid expenses and other current assets	(343,337)	(113,200)
Accounts payable	176,985	(102,763)
Accrued expenses and other liabilities	26,761	(1,181,457)
Tax refund receivable	(4,877,851)	(71,586)
Net cash used in operating activities	(11,518,302)	(5,173,080)
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from sales and maturities of short-term investments	24,900,000
Purchases of short-term investments	(12,118,563)
Purchase of property and equipment	(40,601)	(1,226)
Cash paid for internally developed patents	(79,336)	(15,874)
Net cash provided by (used in) investing activities	12,661,500	(17,100)
CASH FLOWS FROM FINANCING ACTIVITIES:
Payments of deferred offering costs	(179,743)
Proceeds from exercises of warrants	31,310,137	30,324
Proceeds from issuance of common stock in at the market offering, net of offering costs	22,780,729
Proceeds from issuance of common units, net of issuance costs		12,668,784
Proceeds from issuance of notes payable	632,000
Proceeds from issuance of common stock from Employee Stock Purchase Plan	56,739
Proceeds from exercises of stock options	36,175
Payments of notes payable		(156,145)
Net cash provided by financing activities	54,636,037	12,542,963
Net increase in cash and cash equivalents and restricted cash	55,779,235	7,352,783
Cash, cash equivalents and restricted cash at beginning of period	8,996,860	34,353,129
Cash, cash equivalents and restricted cash at end of period	$ 64,776,095	$ 41,705,912

Nature of Business and Basis of Presentation

6 Months Ended

Jun. 30, 2020

Accounting Policies [Abstract]

Nature of Business and Basis of Presentation

1. Nature of Business and Basis of Presentation

Nature of Business

Altimmune, Inc., headquartered in Gaithersburg, Maryland, together with its subsidiaries (collectively, the “Company” or “Altimmune”) is a clinical stage biopharmaceutical company incorporated under the laws of the State of Delaware.

The Company is focused on developing intranasal vaccines, immune modulating therapies and treatments for liver disease. The Company’s diverse pipeline includes proprietary intranasal vaccines for COVID-19 (AdCOVID), anthrax (NasoShield) and influenza (NasoVAX); an intranasal immune modulating therapeutic for COVID-19 (T-COVID); and next generation peptide therapeutics for NASH (ALT-801) and chronic hepatitis B (HepTcell). Since its inception, the Company has devoted substantially all of its efforts to business planning, research and development, recruiting management and technical staff, and raising capital, and has financed its operations through the issuance of common and preferred stock, long-term debt, and proceeds from research grants and government contracts. The Company has not generated any revenues from the sale of any products to date, and there is no assurance of any future revenues from product sales.

Basis of Presentation

The accompanying unaudited consolidated financial statements are prepared pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”) regarding interim financial reporting. Accordingly, they do not include all of the information and disclosures required by accounting principles generally accepted in the United States (“U.S. GAAP”) for complete consolidated financial statements and should be read in conjunction with the audited consolidated financial statements for the year ended December 31, 2019 included in the annual report on Form 10-K which was filed with the SEC on March 27, 2020. In the opinion of management, the Company has prepared the accompanying unaudited consolidated financial statements on the same basis as the audited consolidated financial statements, and these consolidated financial statements include all adjustments, consisting only of normal recurring adjustments, necessary for a fair presentation of the results of the interim periods presented. The operating results for the interim periods presented are not necessarily indicative of the results expected for the full year 2020 or any future years or periods.

The unaudited consolidated financial statements have been prepared on the basis of continuity of operations, realization of assets and the satisfaction of liabilities in the ordinary course of business. The financial statements do not include any adjustments relating to the recoverability and classification of recorded assets and liabilities that might be necessary should we be unable to continue as a going concern.

Summary of Significant Accounting Policies

6 Months Ended

Jun. 30, 2020

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

During the six months ended June 30, 2020, there have been no significant changes to the Company’s summary of significant accounting policies contained in the Company’s Annual report on Form 10-K for the year ended December 31, 2019 as filed with the SEC, except for the recently adopted accounting standard for investments.

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. The extent to which the COVID-19 pandemic may directly or indirectly impact the Company’s business, financial condition, and results of operations is highly uncertain and subject to change. The Company considered the potential impact of the COVID-19 pandemic on the Company’s estimates and assumptions and determined that there was not a material impact to the Company’s consolidated financial statements as of and for the three and six months ended June 30, 2020. However, actual results could differ from those estimates and there may be changes to the Company’s estimates in future periods.

Recently Issued Accounting Pronouncements - Adopted

In August 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2018-13, Fair Value Measurement (Topic 820) – Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement (“ASU No. 20218-13”). ASU No. 2018-13 was issued to modify and enhance the disclosure requirements for fair value measurements and eliminates certain disclosure requirements, such as the amount of, and reasons for, transfers between Level 1 and Level 2 of the fair value hierarchy. This ASU adds new disclosure requirements for Level 3 measurements and is effective for fiscal years beginning after December 15, 2019 and interim periods within those fiscal years. The Company adopted this guidance effective January 1, 2020 which resulted in expanded disclosures in Note 15 regarding the Company’s recurring Level 3 fair value measurements.

Contingent Consideration

6 Months Ended

Jun. 30, 2020

Business Combinations [Abstract]

Contingent consideration

3. Contingent Consideration

The Company entered into a definitive agreement to acquire all of the equity interests of Spitfire Pharma, Inc. (“Spitfire”) on July 8, 2019. Spitfire was a privately held, preclinical pharmaceutical company developing a novel dual GLP-1/glucagon receptor agonist for the treatment of non-alcoholic steatohepatitis.

The transaction closed on July 12, 2019. The Company issued 1,887,250 unregistered shares of its common stock (the “shares”) as upfront consideration to certain former securityholders of Spitfire (collectively, the “Spitfire Equityholders”), representing an amount equal to $5.0 million less working capital and transaction expense adjustment amounts as defined in the agreement.

The Merger Agreement also includes future contingent payments up to $88.0 million in cash and shares of the Company’s common stock as follows (each, a “Milestone Event”):

•

a one-time payment of $5.0 million (the “IND Milestone Consideration Amount”) within sixty days of the submission of an Investigational New Drug Application (“IND”) to the United States Food and Drug Administration (the “FDA”) or other applicable governmental authority in a foreign jurisdiction, which IND has not been rejected or placed on clinical hold by the FDA or such applicable foreign governmental authority within time specified in the Merger Agreement;

•

a one-time payment of $3.0 million (the “Phase 2 Milestone Consideration Amount” and together with the IND Milestone Consideration Amount, the “Regulatory Milestones”) within sixty days of the initiation of a Phase 2 clinical trial of a product candidate anywhere in the world; and

•

payments of up to $80.0 million upon the achievement of specified worldwide net sales (the “Sales Milestones”) of all products developed using the technology acquired in the License Agreement within ten years following the approval of a new drug application filed with the FDA.

The Regulatory Milestones will be payable in shares of the Company’s Common Stock, with the number of shares of the Company’s Common Stock to be issued in connection with each milestone amount, if any, are dependent on the share price at the time of achievement. The number of any shares issued in consideration for the IND Milestone Consideration Amount will be determined based on lower of (A) the average of the closing prices of our Common Stock as reported on the Nasdaq Global Market for the twenty (20) consecutive trading days prior to the IND Reference Date or (B) $2.95. The value of any shares issued in consideration for the Phase 2 Milestone Consideration Amount shall be determined based the lower of (A) on the average of the closing trading prices of our Common Stock as reported on the Nasdaq Global Market for the twenty (20) consecutive trading days immediately preceding the date of the occurrence of the Phase 2 Milestone Event or (B) $3.54.

The acquisition of Spitfire was accounted for as an asset acquisition instead of a business combination because substantially all of the fair value of the gross assets acquired was concentrated in a single identifiable asset or group of similar identifiable assets, and therefore, the asset was not considered a business. The Company expensed the acquired intellectual property as of the acquisition date as in-process research and development with no alternative future uses. The Company recorded an in-process research and development expense for the up-front consideration during the third quarter of 2019. Transaction costs of $0.6 million were recorded within research and development expense on the Company’s consolidated statements of operations and comprehensive loss during the three and six months ended June 30, 2019.

The future contingent payments related to the Regulatory Milestones are stock-based payments accounted for under FASB Accounting Standards Codification Topic 480, Distinguishing Liabilities From Equity. Such stock-based payments are subject to a lock-up whereby 50% of the shares are released at 3 months and 50% are released at 6 months. As of the acquisition date, the Company estimated future contingent consideration of $2.8 million based upon a Monte Carlo simulation that was risk adjusted based on the probability of achieving the milestones and a discount for lack of marketability, which was expensed to in-process research and development expenses during the third quarter of 2019. The Company remeasured the fair value of the contingent consideration as of June 30, 2020, and increased the liability from March 31, 2020 to $16.4 million primarily due to an increase in the share price during the six months ended June 30, 2020 and an increase in the probability of milestone achievement. The increased change in the liability of $11.9 million and $13.6 million was expensed to research and development expense during the three and six months ended June 30, 2020, respectively.

The future contingent payments related to the Sales Milestones are predominately cash-based payments accounted for under FASB Accounting Standards Codification Topic 450, Contingencies. Accordingly, the Company will recognize the Sales Milestones when the contingency is resolved and the amount is paid or payable.

Net Loss Per Share

6 Months Ended

Jun. 30, 2020

Earnings Per Share [Abstract]

Net Loss Per Share

4. Net Loss Per Share

Because the Company has reported a net loss attributable to common stockholders for all periods presented, basic and diluted net loss per share attributable to common stockholders are the same for all periods presented. For periods presented, all unvested restricted stock, common stock warrants, and stock options have been excluded from the computation of diluted weighted-average shares outstanding because such securities would have an antidilutive impact.

Potential common shares issuable upon conversion, vesting or exercise of unvested restricted stock, common stock warrants, and stock options that are excluded from the computation of diluted weighted-average shares outstanding, as they are anti-dilutive, are as follows:

	For the Three and Six Months Ended		For the Three and Six Months Ended
	June 30, 2020		June 30, 2019
Common stock warrants		2,150,285		10,386,256
Common stock options		1,527,978		873,066
Restricted stock		304,686		323,262

Intangible Assets

6 Months Ended

Jun. 30, 2020

Goodwill And Intangible Assets Disclosure [Abstract]

Intangible Assets

5. Intangible Assets

The Company’s intangible assets consisted of the following:

	June 30, 2020
	Estimated Useful Lives	Gross Carrying Value		Accumulated Amortization			Net Book Value
Internally developed patents	6-10 years	$	825,659	$	(466,866	)	$	358,793
Acquired licenses	16-20 years		285,000		(277,105	)		7,895
Total intangible assets subject to amortization			1,110,659		(743,971	)		366,688
IPR&D assets	Indefinite		12,418,967		—			12,418,967
Total		$	13,529,626	$	(743,971	)	$	12,785,655

	December 31, 2019
	Estimated Useful Lives	Gross Carrying Value		Accumulated Amortization			Net Book Value
Internally developed patents	6-10 years	$	746,323	$	(448,874	)	$	297,449
Acquired licenses	16-20 years		285,000		(269,221	)		15,779
Total intangible assets subject to amortization			1,031,323		(718,095	)		313,228
IPR&D assets	Indefinite		12,418,967		—			12,418,967
Total		$	13,450,290	$	(718,095	)	$	12,732,195

Amortization expense of intangible assets was $12,025 and $14,836 for the three months ended June 30, 2020 and 2019, and $25,876 and $107,580 for the six months ended June 30, 2020 and 2019, respectively. Amortization expense was classified as research and development expenses in the accompanying unaudited consolidated statements of operations and comprehensive loss.

As of June 30, 2020, future estimated amortization expense are as follows:

Years ending December 31,
The remainder of 2020	$	20,596
2021		27,687
2022		27,687
2023		27,687
2024		23,781
2025 and thereafter		239,250
Total	$	366,688

Accrued Expenses

6 Months Ended

Jun. 30, 2020

Payables And Accruals [Abstract]

Accrued Expenses

6. Accrued Expenses

Accrued expenses and other current liabilities consist of the following:

	June 30, 2020		December 31, 2019
Accrued professional services	$	472,329	$	429,467
Accrued payroll and employee benefits		956,584		1,183,130
Accrued interest		10,240		5,047
Accrued research and development		2,343,629		1,966,111
Lease obligation, current portion (see Note 12)		273,276		259,449
Deferred revenue		33,691		61,563
Total accrued expenses	$	4,089,749	$	3,904,767

Notes Payable

6 Months Ended

Jun. 30, 2020

Debt Disclosure [Abstract]

Notes Payable

7. Notes Payable

Paycheck Protection Program

On April 7, 2020, the Company applied for a loan from ServisFirst Bank, as lender, pursuant to the Paycheck Protection Program of the Coronavirus Aid, Relief, and Economic Security Act (the “CARES Act”) as administered by the U.S. Small Business Administration (the "SBA"). On April 13, 2020, the Loan was approved and the Company received the proceeds from a loan in the amount of $632,000 (the “PPP Loan”).

The PPP Loan, which took the form of a promissory note (the “Promissory Note”), was set to mature on April 7, 2022 and bore interest at a rate of 1% per annum. Monthly principal and interest payments, less the amount of any potential forgiveness (discussed below), was to commence on November 7, 2020. The Company did not provide any collateral or guarantees for the PPP Loan, nor did the Company pay any facility charge to obtain the PPP Loan. The Promissory Note provided for customary events of default, including, among others, those relating to failure to make payment, bankruptcy, breaches of representations and material adverse effects. The Company could prepay the principal of the PPP Loan at any time without incurring any prepayment charges.

All or a portion of the Loan may be forgiven by the SBA and lender upon application by the Company upon documentation of expenditures in accordance with the SBA requirements. Subsequent to the quarter ended June 30, 2020, the Company received approximately $136.2 million in net proceeds from warrant exercises, ATM usage, and the public offering of its common stock and decided to voluntarily extinguish the Promissory Note on July 21, 2020 by paying the outstanding principal and accrued interest in cash.

Other Long-Term Liabilities

6 Months Ended

Jun. 30, 2020

Other Liabilities Disclosure [Abstract]

Other Long-Term Liabilities

8. Other Long-Term Liabilities

The Company’s other long-term liabilities are summarized as follows:

	June 30, 2020		December 31, 2019
Lease obligation, long-term portion (see Note 12)	$	1,344,779	$	1,484,679
Common stock warrant liability (see Note 10)		10,000		10,000
Economic conditional grants		250,000		250,000
Other		110,245		120,196
Total other long-term liabilities	$	1,715,024	$	1,864,875

At-the-Market Offering

6 Months Ended

Jun. 30, 2020

Text Block [Abstract]

At-the-Market Offering

9. At-the-Market Offering

On March 27, 2020, the Company entered into an Equity Distribution Agreement (the “Agreement”) with JMP Securities LLC, serving as placement agent (the “Placement Agent”) with respect to an at-the-market offering program under which the Company may offer and sell, from time to time at its sole discretion, shares of its common stock, par value $0.0001 per share (the “Common Stock”), having an aggregate offering price of up to $50.0 million (the “Shares”) through the Placement Agent (the “Offering”).

Any Shares offered and sold in the Offering will be issued pursuant to the Company’s Registration Statement on Form S-3 filed with the Securities and Exchange Commission (the “SEC”) on April 4, 2019, which was declared effective on April 12, 2019, the prospectus supplement relating to the Offering filed with the SEC on March 27, 2020 and any applicable additional prospectus supplements related to the Offering that form a part of the Registration Statement. The aggregate market value of Shares eligible for sale in the Offering and under the Equity Distribution Agreement will be subject to the limitations of General Instruction I.B.6 of Form S-3, to the extent required under such instruction. The Company offered Shares having an aggregate offering price of $18.9 million pursuant to the prospectus supplement filed with the SEC on March 27, 2020.

On June 1, 2020, the Company filed an amendment to the Agreement which amended the prospectus supplement dated March 27, 2020 to increase the aggregate offering price to $50.0 million.

As of June 30, 2020, the Company has sold 2,965,144 shares of Common Stock under the Agreement resulting in $22.8 million in net proceeds, leaving $26.3 million available to be sold under the amended Agreement. As of June 30, 2020, the Company recorded approximately $0.3 million of offering costs which offset the proceeds received from the shares sold through June 30, 2020 and recognized approximately $0.2 million of deferred offering costs which will offset future proceeds received under the Agreement.

Subsequent to the quarter ended June 30, 2020, the Company sold 234,856 shares of Common Stock under the Equity Distribution Agreement, that resulted in $2.5 million in net proceeds, leaving $23.7 million available to be sold under the amended Agreement.

Warrants

6 Months Ended

Jun. 30, 2020

Equity [Abstract]

Warrants

10. Warrants

A summary of warrant activity during the six months ended June 30, 2020 is as follows:



Warrants outstanding, December 31, 2019	10,384,706
Warrants issued due to anti-dilution features triggered from Registered Direct Offering	1,358
Exercises	(8,235,779	)
Warrants outstanding, June 30, 2020	2,150,285

During the six months ended June 30, 2020, the Company received net proceeds of $31.3 million from warrant exercises.

For warrants classified as a liability, the following is a summary of the periodic changes in their fair value during the six months ended June 30, 2020:

Balance, December 31, 2019	$	10,000
Changes in fair value		—
Balance, June 30, 2020	$	10,000

Subsequent to the quarter ended June 30, 2020, there were additionally 1,983,110 warrants exercised resulting in net proceeds of $9.6 million and 1,630,436 pre-funded warrants issued in connection with a Public Offering (see Note 16).

Stock-Based Compensation

6 Months Ended

Jun. 30, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation

11. Stock-Based Compensation

Stock Options

The Company’s stock option awards generally vest over four years and typically have a contractual life of ten years. At June 30, 2020, there was $1.9 million of unrecognized compensation cost related to stock options, which is expected to be recognized over a weighted-average period of 3.06 years. During the six months ended June 30, 2020, the Company granted 520,500 stock options with a weighted average exercise price of $2.31 and per share weighted average grant date fair value of $1.83.

Information related to stock options outstanding at June 30, 2020 is as follows:

	Number of Stock Options		Weighted- average Exercise Price		Weighted- average Remaining Contractual Term (Years)		Aggregate Intrinsic Value
Outstanding		1,477,153	$	3.65		5.96	$	12,804,940
Exercisable		416,022	$	5.97		5.69	$	3,097,502
Unvested		1,061,131	$	2.74		6.07	$	9,707,438

Restricted Stock

At June 30, 2020, the Company had unvested restricted stock of 195,161 shares with total unrecognized compensation expense of $0.7 million, which the Company expects to recognize over a weighted average period of approximately 2.42 years. During the six months ended June 30, 2020, the Company released 40,505 shares of common stock from restriction as a result of the vesting of restricted stock.

Restricted Stock Units

During the three months ended June 30, 2020, the Company granted 109,525 shares of restricted stock units which vest during the third quarter of 2020. At June 30, 2020, the Company had unvested restricted stock units of 109,525 shares with total unrecognized compensation expense of $0.9 million, which the Company expects to recognize over a weighted average period of approximately 0.25 years.

2019 Employee Stock Purchase Plan

Under the Employee Stock Purchase Plan (“ESPP”), employees purchased 38,809 shares for $56,739 during the six months ended June 30, 2020. During the three and six months ended June 30, 2020, the Company recognized compensation expense of $20,372 and $35,084, respectively.

Stock-based Compensation Expense

Stock-based compensation expense is classified in the unaudited consolidated statements of operations and comprehensive loss for the three and six months ended June 30, 2020 and 2019 as follows:

	For the Three Months Ended June 30,				For the Six Months Ended June 30,
	2020		2019		2020		2019
Research and development	$	77,939	$	92,060	$	106,939	$	168,684
General and administrative		252,571		197,712		438,492		528,802
Total	$	330,510	$	289,772	$	545,431	$	697,486

Operating Leases

6 Months Ended

Jun. 30, 2020

Leases [Abstract]

Operating Leases

12. Operating Leases

The Company rents office and laboratory space in the United States. The Company also leases office equipment under a non-cancellable equipment lease through December 2022. Rent expense during the three and six months ended June 30, 2020 under all of the Company’s operating leases was $86,295 and $173,894, respectively. Rent expense during the three and six months ended June 30, 2019 was $83,903 and $174,079, respectively. Rent expense includes short-term leases and variable lease costs that are not included in the lease obligation.

Short-term leases are leases having a term of twelve months or less. The Company recognizes short-term leases on a straight-line basis and does not record a related lease asset or liability for such leases.

The office space lease provides for increases in future minimum annual rental payments as defined in the lease agreements. The Company has determined the lease renewal option is not reasonably certain.

The cash paid for operating lease liabilities for the three and six months ended June 30, 2020 was $64,193 and $126,073, respectively.

Supplemental other information related to the operating leases balance sheet information is as follows:

	June 30, 2020
Operating lease obligations	$	1,618,055
Operating lease right-of-use assets	$	662,074
Weighted-average remaining lease term		4.83
Weighted-average discount rate		8.0	%

Maturities of lease liabilities is as follows:

Year ending December 31,
The remainder of 2020	$	194,596
2021		393,542
2022		400,198
2023		407,054
2024		414,116
2025 and thereafter		138,831
Total lease payments		1,948,337
Less imputed interest		(330,282	)
Total	$	1,618,055

Income Taxes

6 Months Ended

Jun. 30, 2020

Income Tax Disclosure [Abstract]

Income Taxes

13. Income Taxes

In response to global pandemic associated with COVID-19, President Donald Trump signed into law the Coronavirus Aid, Relief, and Economic Security Act (the “CARES Act”) on March 27, 2020. The CARES Act provided both stimulus measures and a number of tax provisions, including: temporary changes regarding the utilization and carry back of net operating losses, temporary changes to the prior and future limitations on interest deductions, technical corrections from prior tax legislation for tax depreciation of qualified improvement property, and certain refundable employee retention credits. The CARES Act enables the Company to file a refund claim to reflect a refund of its 2016 tax liability by carrying back its 2018, 2019 and 2020 losses to fully offset this liability. The refund claim attributable to the 2018 and 2019 tax years has been recorded as a discrete item in the income tax benefit for the three months ended March 31, 2020 of $2.9 million. In addition, the Company is currently estimating it will be able to carry back a portion of its current and forecasted 2020 net operating losses as of the end of the year and has included an estimate in its annual effective tax rate calculation as of June 30, 2020, which resulted in an additional income tax benefit of $1.0 million recorded during the six months ended June 30, 2020.

On June 12, 2020, the Comptroller of Maryland issued a report announcing that the state decoupled from the CARES Act loss carryback provisions for the 2020 year only, but indicated uncertainty as to whether the General Assembly would pass a measure to decouple from all years in the CARES Act and not process amended filings in the interim. As a result, an additional discrete item in the income tax benefit of $1.0 million was recognized for the three months ended June 30, 2020 related to the release of valuation allowance related to losses that could potentially be carried back to the 2016 tax year under current law.

Accordingly, the Company has recognized a total tax benefit of $4.8 million for the six months ended June 30, 2020.

- Definition

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

+ References + Details

Commitments and Contingencies

6 Months Ended

Jun. 30, 2020

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

14. Commitments and Contingencies

Spitfire Acquisition

As disclosed in Note 3, the Company is obligated to make payments of up to $80.0 million upon the achievement of specified worldwide net sales of all products developed using the technology acquired from Spitfire Pharma Inc. within ten years following the approval of a new drug application filed with the FDA.

PER.C6 License Agreement Expansion

On April 2, 2020, the Company entered into Amendment No. 3 to the Second Restated License Agreement (the “Amendment”), by and between the Company and Janssen Vaccines & Prevention B.V. (formerly known as Crucell Holland B.V.) (as amended by Amendment No. 1 to Second Restated License Agreement and Amendment No. 2 to Second Restated License Agreement, together with the Amendment, the “License Agreement”). Pursuant to the Amendment, the field of licenses granted to the Company for the use of the PER.C6 cell line under the License Agreement is expanded to cover COVID-19 caused by SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), in addition to the existing licenses related to Bacillus anthracis and influenza virus. All capitalized terms not defined herein shall have the meanings assigned to them in the Amendment or the License Agreement, as applicable.

Pursuant to the Amendment, the Company agreed to pay certain additional development-based milestone payments through approval of licensed products by the FDA for the treatment or prevention of COVID-19, up to an aggregate amount of $1.2 million. The Company also agreed to pay royalty payments as a percentage of net sales of products to a royalty stacking reduction and minimum annual royalty payments, until the expiration of the term of the License Agreement, as amended. As of June 30, 2020, payments made under the License Agreement were de minimis.

Litigation

In December 2019, a complaint was filed by Dr. De-Chu Christopher Tang (“Plaintiff”) against the Company in U.S. District Court for the Eastern District of Texas. The Plaintiff amended the complaint in February 2020 to include Vipin K. Garg and David J. Drutz as defendants, in addition to the Company (Dr. Garg, Dr. Drutz, and the Company are collectively referred to as “Defendants”). In March 2020 the Defendants’ filed a motion to dismiss the complaint. The Court denied the motion without prejudice and allowed Plaintiff an opportunity to file an amended complaint. Plaintiff’s second amended complaint was filed on April 17, 2020, and Defendants filed a motion to dismiss that complaint on May 1, 2020. Plaintiff, who is representing himself, alleges five causes of action as follows: (1) Defendants’ alleged retention of Plaintiff’s lab notebooks; (2) alleged plagiarism based on publishing an article without naming Plaintiff as an author; (3) use of the Adhigh System, which Plaintiff alleges he developed; (4) allegations that Defendants manipulated the Company’s stock and caused a decrease in value; and (5) allegations that the Defendants “wast[ed] government grant money and poison[ed] science by leaving data to rot.” A hearing on Defendants’ motion to dismiss was held on May 20, 2020, and the motion is currently pending. The Company believes the allegations in the complaint are without merit and intends to vigorously defend the litigation. However, the outcome of this legal proceeding is uncertain at this time and the Company cannot reasonably estimate a range of loss, if any. Accordingly, the Company has not accrued any liability associated with this action. The Company is a party in various other contractual disputes, litigation, and potential claims arising in the ordinary course of business none of which are currently reasonably possible or probable of material loss.

Fair Value Measurement

6 Months Ended

Jun. 30, 2020

Fair Value Disclosures [Abstract]

Fair Value Measurement

15. Fair Value Measurement

The Company’s assets and liabilities measured at fair value on a recurring basis at June 30, 2020 consisted of the following:

	Fair Value Measurement at June 30, 2020
	Total		Level 1		Level 2		Level 3
Recurring fair value measurements
Cash equivalents - money market funds	$	38,011,208	$	38,011,208	$	—	$	—
Short-term investments		15,484,402		—		15,484,402		—
Contingent consideration		16,390,000		—		—		16,390,000
Warrant liability		10,000		—		—		10,000

The Company’s assets and liabilities measured at fair value on a recurring basis at December 31, 2019 consisted of the following:

	Fair Value Measurement at December 31, 2019
	Total		Level 1		Level 2		Level 3
Recurring fair value measurements
Cash equivalents - money market funds	$	8,034,640	$	8,034,640	$	—	$	—
Short-term investments		28,277,386		—		28,277,386		—
Contingent consideration		2,750,000		—		—		2,750,000
Warrant liability		10,000		—		—		10,000

Assets recorded at fair value on a nonrecurring basis, such as property and equipment and intangible assets are recognized at fair value when they are impaired.

Cash equivalents and short-term investments have been initially valued at the transaction price and subsequently valued, at the end of each reporting period, utilizing third party pricing services or other market observable data. The pricing services utilize industry standard valuation models, including both income and market-based approaches and observable market inputs to determine value. Short-term investments had quoted prices at June 30, 2020 as shown below:

	June 30, 2020
	Amortized Cost		Unrealized Gain (Loss)		Market Value

Certificate of deposit	$	5,000,000	$	—	$	5,000,000
Financial and corporate debt securities		10,475,942		8,460		10,484,402
Total	$	15,475,942	$	8,460	$	15,484,402

The fair value of contingent payments classified as a liability was based on the regulatory milestones described in Note 3 and estimated using the Monte Carlo simulation valuation model with Level 3 inputs. The following table is a reconciliation of the beginning and ending balance of contingent consideration liability:

Balance at December 31, 2019	$	2,750,000
Change in fair value		13,640,000
Balance at June 30, 2020	$	16,390,000

The assumptions used to estimate the fair value of contingent payments that are classified as a liability at June 30, 2020 include the following significant unobservable inputs:

Unobservable input	Value or Range	Weighted Average

Expected volatility	112.9%	112.9%
Risk-free interest rate	0.16%	0.16%
Cost of capital	30.0%	30.0%
Discount for lack of marketability	14%-22%	18.0%
Probability of payment	52%-83%	76%
Projected year of payment	2020-2022	2020

The Company’s warrant liability is valued using the Monte Carlo simulation valuation model. If applicable, the Company will recognize transfers into and out of levels within the fair value hierarchy at the end of the reporting period in which the actual event or change in circumstance occurs.

There were no transfers into and out of any of the levels of the fair value hierarchy as of June 30, 2020 and December 31, 2019.

- Definition

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

+ References + Details

Subsequent Events

6 Months Ended

Jun. 30, 2020

Subsequent Events [Abstract]

Subsequent Events

16. Subsequent Events

Public Offering

On July 16, 2020, the Company offered and sold (i) 3,369,564 shares of common stock, at a price to the public of $23.00 per share, and (ii) pre-funded warrants of the Company to purchase 1,630,436 shares of common stock at an exercise price equal to $0.0001 per share (the “Pre-Funded Warrants”), at a price to the public of $22.9999 per share of common stock underlying the Pre-Funded Warrants (equal to the public offering price per share of Common Stock, minus the exercise price of each Pre-Funded Warrant). The Pre-Funded Warrants are exercisable at any time, provided that each Pre-Funded Warrant holder will be prohibited from exercising such Pre-Funded Warrants into shares of the Company’s common stock if, as a result of such exercise, the holder, together with its affiliates, would own more than 4.99% of the total number of shares of the Company’s common stock then issued and outstanding, which percentage may change at the holders’ election to any other number less than or equal to 19.99% upon 61 days’ notice to the Company. The gross proceeds of this offering were approximately $132.2 million, which includes the exercise in full of the underwriters’ option to purchase an additional 750,000 shares of common stock, before deducting underwriting discounts and commissions and offering expenses. The net proceeds of this offering were approximately $124.0 million, after deducting underwriting discounts and commissions and estimated offering expenses payable by the Company.

Summary of Significant Accounting Policies (Policies)	6 Months Ended
Summary of Significant Accounting Policies (Policies)	Jun. 30, 2020
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. The extent to which the COVID-19 pandemic may directly or indirectly impact the Company’s business, financial condition, and results of operations is highly uncertain and subject to change. The Company considered the potential impact of the COVID-19 pandemic on the Company’s estimates and assumptions and determined that there was not a material impact to the Company’s consolidated financial statements as of and for the three and six months ended June 30, 2020. However, actual results could differ from those estimates and there may be changes to the Company’s estimates in future periods.
New Accounting Pronouncements - Adopted	Recently Issued Accounting Pronouncements - Adopted In August 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2018-13, Fair Value Measurement (Topic 820) – Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement (“ASU No. 20218-13”). ASU No. 2018-13 was issued to modify and enhance the disclosure requirements for fair value measurements and eliminates certain disclosure requirements, such as the amount of, and reasons for, transfers between Level 1 and Level 2 of the fair value hierarchy. This ASU adds new disclosure requirements for Level 3 measurements and is effective for fiscal years beginning after December 15, 2019 and interim periods within those fiscal years. The Company adopted this guidance effective January 1, 2020 which resulted in expanded disclosures in Note 15 regarding the Company’s recurring Level 3 fair value measurements.

Net Loss Per Share (Tables)

6 Months Ended

Jun. 30, 2020

Earnings Per Share [Abstract]

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share

	For the Three and Six Months Ended		For the Three and Six Months Ended
	June 30, 2020		June 30, 2019
Common stock warrants		2,150,285		10,386,256
Common stock options		1,527,978		873,066
Restricted stock		304,686		323,262

Intangible Assets (Tables)

6 Months Ended

Jun. 30, 2020

Goodwill And Intangible Assets Disclosure [Abstract]

Schedule of Intangible Assets

The Company’s intangible assets consisted of the following:

	June 30, 2020
	Estimated Useful Lives	Gross Carrying Value		Accumulated Amortization			Net Book Value
Internally developed patents	6-10 years	$	825,659	$	(466,866	)	$	358,793
Acquired licenses	16-20 years		285,000		(277,105	)		7,895
Total intangible assets subject to amortization			1,110,659		(743,971	)		366,688
IPR&D assets	Indefinite		12,418,967		—			12,418,967
Total		$	13,529,626	$	(743,971	)	$	12,785,655

	December 31, 2019
	Estimated Useful Lives	Gross Carrying Value		Accumulated Amortization			Net Book Value
Internally developed patents	6-10 years	$	746,323	$	(448,874	)	$	297,449
Acquired licenses	16-20 years		285,000		(269,221	)		15,779
Total intangible assets subject to amortization			1,031,323		(718,095	)		313,228
IPR&D assets	Indefinite		12,418,967		—			12,418,967
Total		$	13,450,290	$	(718,095	)	$	12,732,195

Schedule of Future Estimated Amortization Expense

As of June 30, 2020, future estimated amortization expense are as follows:

Years ending December 31,
The remainder of 2020	$	20,596
2021		27,687
2022		27,687
2023		27,687
2024		23,781
2025 and thereafter		239,250
Total	$	366,688

Accrued Expenses (Tables)

6 Months Ended

Jun. 30, 2020

Payables And Accruals [Abstract]

Schedule of Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consist of the following:

	June 30, 2020		December 31, 2019
Accrued professional services	$	472,329	$	429,467
Accrued payroll and employee benefits		956,584		1,183,130
Accrued interest		10,240		5,047
Accrued research and development		2,343,629		1,966,111
Lease obligation, current portion (see Note 12)		273,276		259,449
Deferred revenue		33,691		61,563
Total accrued expenses	$	4,089,749	$	3,904,767

Other Long-Term Liabilities (Tables)

6 Months Ended

Jun. 30, 2020

Other Liabilities Disclosure [Abstract]

Summary of Other Long-Term Liabilities

The Company’s other long-term liabilities are summarized as follows:

	June 30, 2020		December 31, 2019
Lease obligation, long-term portion (see Note 12)	$	1,344,779	$	1,484,679
Common stock warrant liability (see Note 10)		10,000		10,000
Economic conditional grants		250,000		250,000
Other		110,245		120,196
Total other long-term liabilities	$	1,715,024	$	1,864,875

Warrants (Tables)

6 Months Ended

Jun. 30, 2020

Equity [Abstract]

Summary of Warrant Activity

A summary of warrant activity during the six months ended June 30, 2020 is as follows:



Warrants outstanding, December 31, 2019	10,384,706
Warrants issued due to anti-dilution features triggered from Registered Direct Offering	1,358
Exercises	(8,235,779	)
Warrants outstanding, June 30, 2020	2,150,285

Summary of Periodic Changes in Fair Value of Warrant Liability

For warrants classified as a liability, the following is a summary of the periodic changes in their fair value during the six months ended June 30, 2020:

Balance, December 31, 2019	$	10,000
Changes in fair value		—
Balance, June 30, 2020	$	10,000

Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Information Related to Stock Options Outstanding

Information related to stock options outstanding at June 30, 2020 is as follows:

	Number of Stock Options		Weighted- average Exercise Price		Weighted- average Remaining Contractual Term (Years)		Aggregate Intrinsic Value
Outstanding		1,477,153	$	3.65		5.96	$	12,804,940
Exercisable		416,022	$	5.97		5.69	$	3,097,502
Unvested		1,061,131	$	2.74		6.07	$	9,707,438

Schedule of Stock-based Compensation Expense

Stock-based compensation expense is classified in the unaudited consolidated statements of operations and comprehensive loss for the three and six months ended June 30, 2020 and 2019 as follows:

	For the Three Months Ended June 30,				For the Six Months Ended June 30,
	2020		2019		2020		2019
Research and development	$	77,939	$	92,060	$	106,939	$	168,684
General and administrative		252,571		197,712		438,492		528,802
Total	$	330,510	$	289,772	$	545,431	$	697,486

Operating Leases (Tables)

6 Months Ended

Jun. 30, 2020

Leases [Abstract]

Summary of Supplemental other Information Related to Operating Leases Balance Sheet

Supplemental other information related to the operating leases balance sheet information is as follows:

	June 30, 2020
Operating lease obligations	$	1,618,055
Operating lease right-of-use assets	$	662,074
Weighted-average remaining lease term		4.83
Weighted-average discount rate		8.0	%

Summary of Maturities of Lease Liabilities

Maturities of lease liabilities is as follows:

Year ending December 31,
The remainder of 2020	$	194,596
2021		393,542
2022		400,198
2023		407,054
2024		414,116
2025 and thereafter		138,831
Total lease payments		1,948,337
Less imputed interest		(330,282	)
Total	$	1,618,055

Fair Value Measurement (Tables)

6 Months Ended

Jun. 30, 2020

Fair Value Disclosures [Abstract]

Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis

The Company’s assets and liabilities measured at fair value on a recurring basis at June 30, 2020 consisted of the following:

	Fair Value Measurement at June 30, 2020
	Total		Level 1		Level 2		Level 3
Recurring fair value measurements
Cash equivalents - money market funds	$	38,011,208	$	38,011,208	$	—	$	—
Short-term investments		15,484,402		—		15,484,402		—
Contingent consideration		16,390,000		—		—		16,390,000
Warrant liability		10,000		—		—		10,000

The Company’s assets and liabilities measured at fair value on a recurring basis at December 31, 2019 consisted of the following:

	Fair Value Measurement at December 31, 2019
	Total		Level 1		Level 2		Level 3
Recurring fair value measurements
Cash equivalents - money market funds	$	8,034,640	$	8,034,640	$	—	$	—
Short-term investments		28,277,386		—		28,277,386		—
Contingent consideration		2,750,000		—		—		2,750,000
Warrant liability		10,000		—		—		10,000

Schedule of Short Term Investments

Short-term investments had quoted prices at June 30, 2020 as shown below:

	June 30, 2020
	Amortized Cost		Unrealized Gain (Loss)		Market Value

Certificate of deposit	$	5,000,000	$	—	$	5,000,000
Financial and corporate debt securities		10,475,942		8,460		10,484,402
Total	$	15,475,942	$	8,460	$	15,484,402

Schedule of Reconciliation of Beginning and Ending Balance of Contingent Consideration Liability

Balance at December 31, 2019	$	2,750,000
Change in fair value		13,640,000
Balance at June 30, 2020	$	16,390,000

Summary of Assumptions Used to Estimate Fair Value of Contingent Payments

The assumptions used to estimate the fair value of contingent payments that are classified as a liability at June 30, 2020 include the following significant unobservable inputs:

Unobservable input	Value or Range	Weighted Average

Expected volatility	112.9%	112.9%
Risk-free interest rate	0.16%	0.16%
Cost of capital	30.0%	30.0%
Discount for lack of marketability	14%-22%	18.0%
Probability of payment	52%-83%	76%
Projected year of payment	2020-2022	2020

- Definition

Tabular disclosure of financial instruments measured at fair value, including those classified in shareholders' equity measured on a recurring or nonrecurring basis. Disclosures include, but are not limited to, fair value measurements recorded and the reasons for the measurements, level within the fair value hierarchy in which the fair value measurements are categorized and transfers between levels 1 and 2. Nonrecurring fair value measurements are those that are required or permitted in the statement of financial position in particular circumstances.

+ References + Details

Contingent Consideration - Additional Information (Detail) - USD ($)		3 Months Ended		6 Months Ended
	Jul. 12, 2019	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Business Acquisition [Line Items]
Estimated future contingent consideration		$ 16,390,000		$ 16,390,000		$ 2,750,000
Change in value of contingent consideration for acquired in-process research and development				13,640,000
Spitfire Pharma, Inc. [Member]
Business Acquisition [Line Items]
Agreement date	Jul. 08, 2019
Unregistered shares of common stock	1,887,250
Up-front consideration	$ 5,000,000
Transaction cost recorded within research and development expense			$ 600,000		$ 600,000
Spitfire Pharma, Inc. [Member] \| Investigational New Drug Application Milestone [Member]
Business Acquisition [Line Items]
Future contingent payments	$ 5,000,000
Future contingent payment term	60 days
Number of consecutive trading days	20 days
Condiseration amount	$ 2.95
Spitfire Pharma, Inc. [Member] \| Investigational New Drug Application and Regulatory Milestones [Member]
Business Acquisition [Line Items]
Future contingent payments	$ 3,000,000
Future contingent payment term	60 days
Number of consecutive trading days	20 days
Condiseration amount	$ 3.54
Spitfire Pharma, Inc. [Member] \| Sales Milestones [Member]
Business Acquisition [Line Items]
Future contingent payments	$ 80,000,000
License agreement term	10 years
Spitfire Pharma, Inc. [Member] \| Regulatory Milestones [Member]
Business Acquisition [Line Items]
Upfront consideration release at 3 months	50.00%
Upfront consideration release at 6 months	50.00%
Spitfire Pharma, Inc. [Member] \| Regulatory Milestones [Member] \| Monte Carlo Simulation [Member]
Business Acquisition [Line Items]
Estimated future contingent consideration	$ 2,800,000	16,400,000		16,400,000
Change in value of contingent consideration for acquired in-process research and development		$ 11,900,000		$ 13,600,000
Spitfire Pharma, Inc. [Member] \| Maximum [Member] \| Common Stock [Member]
Business Acquisition [Line Items]
Future contingent payments	$ 88,000,000

Net Loss Per Share - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share (Detail) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Common Stock Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	2,150,285	10,386,256	2,150,285	10,386,256
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	1,527,978	873,066	1,527,978	873,066
Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	304,686	323,262	304,686	323,262

Intangible Assets - Schedule of Intangible Assets (Detail) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Schedule Of Intangible Assets [Line Items]
Intangible assets subject to amortization, Gross Carrying Value	$ 1,110,659	$ 1,031,323
Intangible assets subject to amortization, Accumulated Amortization	(743,971)	(718,095)
Intangible assets subject to amortization, Net Book Value	366,688	313,228
Total intangible assets, Gross Carrying Value	13,529,626	13,450,290
Total intangible assets, Net Book Value	12,785,655	12,732,195
IPR&D [Member]
Schedule Of Intangible Assets [Line Items]
Total intangible assets, Gross Carrying Value	12,418,967	12,418,967
Total intangible assets, Net Book Value	12,418,967	12,418,967
Internally Developed Patents [Member]
Schedule Of Intangible Assets [Line Items]
Intangible assets subject to amortization, Gross Carrying Value	825,659	746,323
Intangible assets subject to amortization, Accumulated Amortization	(466,866)	(448,874)
Intangible assets subject to amortization, Net Book Value	$ 358,793	$ 297,449
Internally Developed Patents [Member] \| Minimum [Member]
Schedule Of Intangible Assets [Line Items]
Estimated Useful Lives	6 years	6 years
Internally Developed Patents [Member] \| Maximum [Member]
Schedule Of Intangible Assets [Line Items]
Estimated Useful Lives	10 years	10 years
Acquired Licenses [Member]
Schedule Of Intangible Assets [Line Items]
Intangible assets subject to amortization, Gross Carrying Value	$ 285,000	$ 285,000
Intangible assets subject to amortization, Accumulated Amortization	(277,105)	(269,221)
Intangible assets subject to amortization, Net Book Value	$ 7,895	$ 15,779
Acquired Licenses [Member] \| Minimum [Member]
Schedule Of Intangible Assets [Line Items]
Estimated Useful Lives	16 years	16 years
Acquired Licenses [Member] \| Maximum [Member]
Schedule Of Intangible Assets [Line Items]
Estimated Useful Lives	20 years	20 years

Intangible Assets - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Research and Development [Member]
Schedule Of Intangible Assets [Line Items]
Amortization expense of intangible assets	$ 12,025	$ 14,836	$ 25,876	$ 107,580

Intangible Assets - Schedule of Future Estimated Amortization Expense (Detail) - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
The remainder of 2020	$ 20,596
2021	27,687
2022	27,687
2023	27,687
2024	23,781
2025 and thereafter	239,250
Intangible assets subject to amortization, Net Book Value	$ 366,688	$ 313,228

Accrued Expenses - Schedule of Accrued Expenses and Other Current Liabilities (Detail) - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Accrued Liabilities And Other Liabilities [Abstract]
Accrued professional services	$ 472,329	$ 429,467
Accrued payroll and employee benefits	956,584	1,183,130
Accrued interest	10,240	5,047
Accrued research and development	2,343,629	1,966,111
Lease obligation, current portion (see Note 12)	273,276	259,449
Deferred revenue	33,691	61,563
Total accrued expenses	$ 4,089,749	$ 3,904,767

Notes Payable - Additional Information (Detail) - USD ($)		1 Months Ended	6 Months Ended
	Apr. 13, 2020	Aug. 11, 2020	Jun. 30, 2020
Registered Direct Offering, ATM Usage and Warrant Exercises [Member] \| Subsequent Event [Member]
Debt Instrument [Line Items]
Net proceeds from issuance or sale of equity		$ 136,200,000
Paycheck Protection Program Loan [Member]
Debt Instrument [Line Items]
Proceeds from unsecured loan	$ 632,000
Maturity date			Apr. 07, 2022
Interest rate			1.00%

Other Long-Term Liabilities - Summary of Other Long-Term Liabilities (Detail) - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Other Liabilities Disclosure [Abstract]
Lease obligation, long-term portion (see Note 12)	$ 1,344,779	$ 1,484,679
Common stock warrant liability (see Note 10)	10,000	10,000
Economic conditional grants	250,000	250,000
Other	110,245	120,196
Total other long-term liabilities	$ 1,715,024	$ 1,864,875

At-the-Market Offering - Additional Information (Detail) - USD ($)				1 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 01, 2020	Mar. 27, 2020	Aug. 11, 2020	Jun. 30, 2020	Dec. 31, 2019
Changes In Equity And Comprehensive Income Line Items [Line Items]
Common stock par value	$ 0.0001				$ 0.0001	$ 0.0001
Net proceeds from offering					$ 22,780,729
Equity Distribution Agreement [Member] \| At-The-Market Offering [Member] \| JMP Securities LLC [Member]
Changes In Equity And Comprehensive Income Line Items [Line Items]
Common stock par value			$ 0.0001
Aggregate offering price		$ 50,000,000	$ 18,900,000
Shares of common stock sold	2,965,144
Net proceeds from offering	$ 22,800,000
Common stock available to be sold	26,300,000				26,300,000
Deferred offering costs	200,000				$ 200,000
Issuance costs	$ 300,000
Equity Distribution Agreement [Member] \| At-The-Market Offering [Member] \| JMP Securities LLC [Member] \| Subsequent Event [Member]
Changes In Equity And Comprehensive Income Line Items [Line Items]
Shares of common stock sold				234,856
Net proceeds from offering				$ 2,500,000
Common stock available to be sold				$ 23,700,000
Equity Distribution Agreement [Member] \| At-The-Market Offering [Member] \| JMP Securities LLC [Member] \| Maximum [Member]
Changes In Equity And Comprehensive Income Line Items [Line Items]
Aggregate offering price			$ 50,000,000

Warrants - Summary of Warrant Activity (Detail)	6 Months Ended
Warrants - Summary of Warrant Activity (Detail)	Jun. 30, 2020 shares
Equity [Abstract]
Warrants outstanding, December 31, 2019	10,384,706
Warrants issued due to anti-dilution features triggered from Registered Direct Offering	1,358
Exercises	(8,235,779)
Warrants outstanding, June 30, 2020	2,150,285

Warrants - Additional Information (Detail) - USD ($)	1 Months Ended	6 Months Ended
Warrants - Additional Information (Detail) - USD ($)	Aug. 11, 2020	Jun. 30, 2020	Jun. 30, 2019
Net proceeds from warrant exercises		$ 31,310,137	$ 30,324
Subsequent Event [Member]
Net proceeds from warrant exercises	$ 9,600,000
Number of warrants exercised	1,983,110
Public Offering [Member] \| Subsequent Event [Member]
Pre-funded warrants issued	1,630,436

Warrants - Summary of Periodic Changes in Fair Value of Warrant Liability (Detail) - Level 3 [Member] - Common Stock Warrants [Member]	6 Months Ended
	Jun. 30, 2020 USD ($)
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Balance, December 31, 2019	$ 10,000
Changes in fair value
Balance, June 30, 2020	$ 10,000

Stock-Based Compensation - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2020	Jun. 30, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Employees purchased, value		$ 56,739
Stock-based compensation expense			$ 545,431	$ 697,486
2019 Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Employees purchased, shares			38,809
Employees purchased, value			$ 56,739
Stock-based compensation expense	$ 20,372		$ 35,084
Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option vesting Period			4 years
Stock option expiration Period			10 years
Unrecognized compensation cost, stock options	$ 1,900,000		$ 1,900,000
Unrecognized stock-based compensation expense, period for recognition			3 years 21 days
Number of Stock Options, Granted			520,500
Stock options granted, weighted-average exercise price			$ 2.31
Weighted-average grant date fair value of stock options granted			$ 1.83
Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation expense, period for recognition			2 years 5 months 1 day
Unvested restricted stock, shares	195,161		195,161
Unrecognized compensation expense	$ 700,000		$ 700,000
Common stock issued as result of vesting of restricted stock			40,505
Restricted Stock Units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation expense, period for recognition			3 months
Unvested restricted stock, shares	109,525		109,525
Unrecognized compensation expense	$ 900,000		$ 900,000
Shares granted	109,525

Stock-Based Compensation - Schedule of Information Related to Stock Options Outstanding (Detail)	6 Months Ended
	Jun. 30, 2020 USD ($) $ / shares shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Stock Options, Outstanding \| shares	1,477,153
Number of Stock Options, Exercisable \| shares	416,022
Number of Stock Options, Unvested \| shares	1,061,131
Weighted-average Exercise Price, Outstanding \| $ / shares	$ 3.65
Weighted-average Exercise Price, Exercisable \| $ / shares	5.97
Weighted-average Exercise Price, Unvested \| $ / shares	$ 2.74
Weighted-average Remaining Contractual Term, Outstanding	5 years 11 months 15 days
Weighted-average Remaining Contractual Term, Exercisable	5 years 8 months 8 days
Weighted-average Remaining Contractual Term, Unvested	6 years 25 days
Aggregate Intrinsic Value, Outstanding \| $	$ 12,804,940
Aggregate Intrinsic Value, Exercisable \| $	3,097,502
Aggregate Intrinsic Value, Unvested \| $	$ 9,707,438

Stock-Based Compensation - Schedule of Stock-based Compensation Expense (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock based compensation expense	$ 330,510	$ 289,772	$ 545,431	$ 697,486
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock based compensation expense	77,939	92,060	106,939	168,684
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock based compensation expense	$ 252,571	$ 197,712	$ 438,492	$ 528,802

Operating Leases - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Leases [Abstract]
Non-cancellable lease maturity period			2022-12
Operating lease rent expense	$ 86,295	$ 83,903	$ 173,894	$ 174,079
Cash paid for operating lease liabilities	$ 64,193		$ 126,073

Operating Leases - Summary of Supplemental other Information Related to Operating Leases Balance Sheet (Detail) - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease obligations	$ 1,618,055
Operating lease right-of-use assets	$ 662,074	$ 698,321
Weighted-average remaining lease term	4 years 9 months 29 days
Weighted-average discount rate	8.00%

Operating Leases - Summary of Maturities of Lease Liabilities (Detail)	Jun. 30, 2020 USD ($)
Leases [Abstract]
The remainder of 2020	$ 194,596
2021	393,542
2022	400,198
2023	407,054
2024	414,116
2025 and thereafter	138,831
Total lease payments	1,948,337
Less imputed interest	(330,282)
Total	$ 1,618,055

Income Taxes - Additional Information (Detail)	3 Months Ended	6 Months Ended
Income Taxes - Additional Information (Detail)	Jun. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)
Income Tax Disclosure [Abstract]
Income tax, refund claim	$ 2,900,000	$ 2,900,000
Effective income tax rate reconciliation, additional discrete item of income tax benefit		1,000,000
Additional income tax benefit	1,000,000
Income tax benefit	$ 1,578,782	$ 4,824,661

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Millions	Apr. 02, 2020	Jul. 12, 2019
Janssen Vaccines and Prevention BV [Member] \| License [Member] \| Maximum [Member]
Commitments And Contingencies [Line Items]
Development-based milestone payments	$ 1.2
Spitfire Pharma, Inc. [Member] \| Sales Milestones [Member]
Commitments And Contingencies [Line Items]
Future contingent payments		$ 80.0
License agreement term		10 years

Fair Value Measurement - Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis (Detail) - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	$ 15,484,402	$ 28,277,386
Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	15,484,402	28,277,386
Contingent consideration	16,390,000	2,750,000
Warrant liability	10,000	10,000
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	15,484,402	28,277,386
Fair Value, Measurements, Recurring [Member] \| Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Contingent consideration	16,390,000	2,750,000
Warrant liability	10,000	10,000
Money Market Funds [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	38,011,208	8,034,640
Money Market Funds [Member] \| Fair Value, Measurements, Recurring [Member] \| Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	$ 38,011,208	$ 8,034,640

Fair Value Measurement - Schedule of Short Term Investments (Detail)	Jun. 30, 2020 USD ($)
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 15,475,942
Unrealized Gain (Loss)	8,460
Market Value	15,484,402
Certificate of Deposit [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	5,000,000
Market Value	5,000,000
Financial and Corporate Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	10,475,942
Unrealized Gain (Loss)	8,460
Market Value	$ 10,484,402

Fair Value Measurement - Schedule of Reconciliation of Beginning and Ending Balance of Contingent Consideration Liability (Detail) - Contingent Consideration Liability [Member]	6 Months Ended
	Jun. 30, 2020 USD ($)
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance at December 31, 2019	$ 2,750,000
Change in fair value	13,640,000
Balance at June 30, 2020	$ 16,390,000

Fair Value Measurement - Additional Information (Detail) - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair value transfers, Level 1 to Level 2 assets	$ 0	$ 0
Fair value transfers, Level 2 to Level 1 assets	0	0
Fair value transfers, Level 1 to Level 2 liabilities	0	0
Fair value transfers, Level 2 to Level 1 liabilities	$ 0	$ 0

Subsequent Events - Additional Information (Detail) - USD ($)		6 Months Ended
	Jul. 16, 2020	Jun. 30, 2020
Subsequent Event [Line Items]
Proceeds from issuance of common stock in at the market offering, net of offering costs		$ 22,780,729
Subsequent Event [Member] \| Public Offering [Member]
Subsequent Event [Line Items]
Gross proceeds from offering including exercise of underwriter's option	$ 132,200,000
Subsequent Event [Member] \| Public Offering [Member] \| Pre-Funded Warrants [Member]
Subsequent Event [Line Items]
Number of securities called by warrants or rights	1,630,436
Exercise price of warrants or rights	$ 0.0001
Purchase price of warrants issued	$ 22.9999
Ownership percentage on exercise of warrants without notice, minimum	4.99%
Ownership percentage on exercise of warrants with notice, maximum	19.99%
Notice period to increase ownership percentage on exercise of warrants	61 days
Subsequent Event [Member] \| Public Offering [Member] \| Common Stock [Member]
Subsequent Event [Line Items]
Shares of common stock sold	3,369,564
Public offering price, per share	$ 23.00
Subsequent Event [Member] \| Over-Allotment Option [Member] \| Common Stock [Member]
Subsequent Event [Line Items]
Shares of common stock sold	750,000
Proceeds from issuance of common stock in at the market offering, net of offering costs	$ 124,000,000

Fair Value Measurement - Summary of Assumptions Used to Estimate Fair Value of Contingent Payments (Detail) - Level 3 [Member]	6 Months Ended
	Jun. 30, 2020
Expected Volatility [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	1.129
Expected Volatility [Member] \| Weighted Average [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	1.129
Risk-free Interest Rate [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	0.0016
Risk-free Interest Rate [Member] \| Weighted Average [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	0.0016
Cost of Capital [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	0.300
Cost of Capital [Member] \| Weighted Average [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	0.300
Discount for Lack of Marketability [Member] \| Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	0.14
Discount for Lack of Marketability [Member] \| Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	0.22
Discount for Lack of Marketability [Member] \| Weighted Average [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	0.180
Probability of Payment [Member] \| Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	0.52
Probability of Payment [Member] \| Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	0.83
Probability of Payment [Member] \| Weighted Average [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	0.76
Projected Year of Payment [Member] \| Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	2020
Projected Year of Payment [Member] \| Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	2022
Projected Year of Payment [Member] \| Weighted Average [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	2020