0001117480-21-000025 | 10-Q | XBRL Viewer

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Cover Page - shares	9 Months Ended
Cover Page - shares	Sep. 30, 2021	Oct. 31, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	001-35867
Entity Registrant Name	CHIMERIX, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	33-0903395
Entity Address, Address Line One	2505 Meridian Parkway
Entity Address, Address Line Two	Suite 100
Entity Address, City or Town	Durham
Entity Address, State or Province	NC
Entity Address, Postal Zip Code	27713
City Area Code	919
Local Phone Number	806-1074
Title of each class	Common Stock, par value $0.001 per share
Trading Symbol(s)	CMRX
Name of each exchange on which registered	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		86,862,426
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Central Index Key	0001117480
Current Fiscal Year End Date	--12-31

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 26,174	$ 46,989
Short-term investments, available-for-sale	96,384	31,973
Accounts receivable	53	340
Inventories	1,595	0
Prepaid expenses and other current assets	4,327	2,356
Total current assets	128,533	81,658
Long-term investments	2,035	0
Property and equipment, net of accumulated depreciation	264	214
Operating lease right-of-use assets	2,509	2,825
Other long-term assets	60	26
Total assets	133,401	84,723
Current liabilities:
Accounts payable	1,792	1,283
Accrued liabilities	10,498	7,250
Note payable	14,000	0
Total current liabilities	26,290	8,533
Lease-related obligations	2,525	2,814
Total liabilities	28,815	11,347
Stockholders’ equity:
Preferred stock, $0.001 par value, 10,000,000 shares authorized at September 30, 2021 and December 31, 2020; no shares issued and outstanding as of September 30, 2021 and December 31, 2020	0	0
Common stock, $0.001 par value, 200,000,000 shares authorized at September 30, 2021 and December 31, 2020; 86,848,426 and 62,816,039 shares issued and outstanding as of September 30, 2021 and December 31, 2020, respectively	87	63
Additional paid-in capital	950,597	785,673
Accumulated other comprehensive loss, net	0	0
Accumulated deficit	(846,098)	(712,360)
Total stockholders’ equity	104,586	73,376
Total liabilities and stockholders’ equity	$ 133,401	$ 84,723

Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	86,848,426	62,816,039
Common stock, shares outstanding (in shares)	86,848,426	62,816,039

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Total revenues	$ 107	$ 1,609	$ 1,933	$ 4,252
Operating expenses:
Research and development	13,820	10,018	39,480	27,545
General and administrative	4,887	3,151	13,431	9,466
Acquired in-process research and development	0	0	82,890	0
Total operating expenses	18,707	13,169	135,801	37,011
Loss from operations	(18,600)	(11,560)	(133,868)	(32,759)
Other income:
Interest income and other, net	40	149	130	912
Net loss	(18,560)	(11,411)	(133,738)	(31,847)
Other comprehensive loss:
Unrealized gain (loss) on debt investments, net	11	(97)	0	(2)
Comprehensive loss	$ (18,549)	$ (11,508)	$ (133,738)	$ (31,849)
Per share information:
Net loss, basic (in dollars per share)	$ (0.21)	$ (0.18)	$ (1.59)	$ (0.51)
Net loss, diluted (in dollars per share)	$ (0.21)	$ (0.18)	$ (1.59)	$ (0.51)
Weighted-average shares outstanding, basic (in shares)	86,335,357	62,242,456	84,277,555	62,009,941
Weighted-average shares outstanding, diluted (in shares)	86,335,357	62,242,456	84,277,555	62,009,941
Contract and grant revenue
Total revenues	$ 105	$ 1,591	$ 1,928	$ 4,158
Licensing revenue
Total revenues	$ 2	$ 18	$ 5	$ 94

Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Gain (Loss)	Accumulated Deficit
Increase (Decrease) in Stockholders' Equity
Beginning balance (in shares)		61,590,013
Beginning balance at Dec. 31, 2019	$ 109,952	$ 62	$ 778,693	$ 35	$ (668,838)
Increase (Decrease) in Stockholders' Equity
Share-based compensation	1,326		1,326
Employee stock purchase plan purchases	229		229
Employee stock purchase plan purchases (in shares)		177,193
RSU stock issuance (in shares)		163,133
Comprehensive loss:
Unrealized loss on investments, net	(46)			(46)
Net loss	(10,420)				(10,420)
Comprehensive loss	(10,466)
Ending balance at Mar. 31, 2020	101,041	$ 62	780,248	(11)	(679,258)
Ending balance (in shares) at Mar. 31, 2020		61,930,339
Beginning balance at Dec. 31, 2019	109,952	$ 62	778,693	35	(668,838)
Comprehensive loss:
Unrealized loss on investments, net	(2)
Net loss	(31,847)
Comprehensive loss	(31,849)
Ending balance at Sep. 30, 2020	83,169	$ 63	783,758	33	(700,685)
Ending balance (in shares) at Sep. 30, 2020		62,629,722
Increase (Decrease) in Stockholders' Equity
Beginning balance (in shares)		61,930,339
Beginning balance at Mar. 31, 2020	101,041	$ 62	780,248	(11)	(679,258)
Increase (Decrease) in Stockholders' Equity
Share-based compensation	1,391		1,391
Exercise of stock options	578		578
Exercise of stock options (in shares)		242,079
Comprehensive loss:
Unrealized loss on investments, net	141			141
Net loss	(10,016)				(10,016)
Comprehensive loss	(9,875)
Ending balance at Jun. 30, 2020	93,135	$ 62	782,217	130	(689,274)
Ending balance (in shares) at Jun. 30, 2020		62,172,418
Increase (Decrease) in Stockholders' Equity
Beginning balance (in shares)		62,172,418
Share-based compensation	1,282		1,282
Exercise of stock options	63	$ 1	62
Exercise of stock options (in shares)		20,592
Employee stock purchase plan purchases	197		197
Employee stock purchase plan purchases (in shares)		159,879
RSU stock issuance (in shares)		276,833
Comprehensive loss:
Unrealized loss on investments, net	(97)			(97)
Net loss	(11,411)				(11,411)
Comprehensive loss	(11,508)
Ending balance at Sep. 30, 2020	83,169	$ 63	783,758	33	(700,685)
Ending balance (in shares) at Sep. 30, 2020		62,629,722
Increase (Decrease) in Stockholders' Equity
Beginning balance (in shares)		62,629,722
Beginning balance (in shares)		62,816,039
Beginning balance at Dec. 31, 2020	73,376	$ 63	785,673	0	(712,360)
Increase (Decrease) in Stockholders' Equity
Share-based compensation	2,584		2,584
Exercise of stock options	3,530	$ 1	3,529
Exercise of stock options (in shares)		710,132
Employee stock purchase plan purchases	330		330
Employee stock purchase plan purchases (in shares)		259,837
RSU stock issuance (in shares)		168,752
Issuance of common stock related to asset acquisition	43,445	$ 9	43,436
Issuance of common stock related to asset acquisition (in shares)		8,723,769
Issuance of common stock, net of issuance costs of $7.2 million	107,842	$ 13	107,829
Issuance of common stock, net of issuance costs $7.2 million (in shares)		13,529,750
Comprehensive loss:
Unrealized loss on investments, net	(43)			(43)
Net loss	(97,415)				(97,415)
Comprehensive loss	(97,458)
Ending balance at Mar. 31, 2021	133,649	$ 86	943,381	(43)	(809,775)
Ending balance (in shares) at Mar. 31, 2021		86,208,279
Beginning balance at Dec. 31, 2020	73,376	$ 63	785,673	0	(712,360)
Comprehensive loss:
Unrealized loss on investments, net	0
Net loss	(133,738)
Comprehensive loss	(133,738)
Ending balance at Sep. 30, 2021	104,586	$ 87	950,597	0	(846,098)
Ending balance (in shares) at Sep. 30, 2021		86,848,426
Increase (Decrease) in Stockholders' Equity
Beginning balance (in shares)		86,208,279
Beginning balance at Mar. 31, 2021	133,649	$ 86	943,381	(43)	(809,775)
Increase (Decrease) in Stockholders' Equity
Share-based compensation	3,112		3,112
Exercise of stock options	119		119
Exercise of stock options (in shares)		41,465
Comprehensive loss:
Unrealized loss on investments, net	32			32
Net loss	(17,763)				(17,763)
Comprehensive loss	(17,731)
Ending balance at Jun. 30, 2021	119,149	$ 86	946,612	(11)	(827,538)
Ending balance (in shares) at Jun. 30, 2021		86,249,744
Increase (Decrease) in Stockholders' Equity
Beginning balance (in shares)		86,249,744
Share-based compensation	3,431		3,431
Exercise of stock options	130		130
Exercise of stock options (in shares)		74,588
Employee stock purchase plan purchases	425	$ 1	424
Employee stock purchase plan purchases (in shares)		283,094
RSU stock issuance (in shares)		241,000
Comprehensive loss:
Unrealized loss on investments, net	11			11
Net loss	(18,560)				(18,560)
Comprehensive loss	(18,549)
Ending balance at Sep. 30, 2021	$ 104,586	$ 87	$ 950,597	$ 0	$ (846,098)
Ending balance (in shares) at Sep. 30, 2021		86,848,426
Increase (Decrease) in Stockholders' Equity
Beginning balance (in shares)		86,848,426

Consolidated Statements of Stockholders' Equity (Deficit) (Parenthetical) $ in Millions	3 Months Ended
	Mar. 31, 2021 USD ($)
Statement of Stockholders' Equity [Abstract]
Issuance costs	$ 7.2

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net loss	$ (133,738)	$ (31,847)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation of property and equipment	143	309
Amortization of discount/premium on investments	648	(268)
Share-based compensation	9,127	4,000
Fair value of common stock issued related to asset acquisition	43,445	0
Note payable related to asset acquisition	14,000
Gain on sale of investments	(2)	(1)
Gain on sale of equipment	0	(10)
Lease-related amortization	314	(47)
Changes in operating assets and liabilities:
Accounts receivable	288	855
Inventories	(1,595)	0
Prepaid expenses and other assets	(2,005)	1,284
Accounts payable and accrued liabilities	3,468	(1,268)
Net cash used in operating activities	(65,907)	(26,993)
Cash flows from investing activities:
Purchases of property and equipment	(193)	(60)
Proceeds from sale of property and equipment	0	10
Purchases of short-term investments	(105,355)	(58,895)
Purchases of long-term investments	(9,594)	0
Proceeds from sales of short-term investments	2,007	1,498
Proceeds from maturities of short-term investments	45,850	104,602
Net cash (used in) provided by investing activities	(67,285)	47,155
Cash flows from financing activities:
Proceeds from exercise of stock options	3,780	641
Proceeds from employee stock purchase plan	754	426
Proceeds from issuance of common stock, net of commissions	107,843	0
Net cash provided by financing activities	112,377	1,067
Net (decrease) increase in cash and cash equivalents	(20,815)	21,229
Cash and cash equivalents:
Beginning of period	46,989	16,901
End of period	$ 26,174	$ 38,130

The Business and Summary of Significant Accounting Policies

9 Months Ended

Sep. 30, 2021

Accounting Policies [Abstract]

The Business and Summary of Significant Accounting Policies

Description of Business

Chimerix is a biopharmaceutical company whose mission it is to develop medicines that meaningfully improve and extend the lives of patients facing deadly diseases. In June 2021, the U.S. Food and Drug Administration (FDA) approved TEMBEXA (brincidofovir) for the treatment of smallpox as a medical countermeasure. Our two most advanced clinical-stage development programs are ONC201 and dociparstat sodium (DSTAT). ONC201 is in development for recurrent H3 K27M-mutant glioma. DSTAT is in Phase 3 development as a potential first-line therapy in acute myeloid leukemia (AML).

Basis of Presentation

The accompanying unaudited consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. The accompanying unaudited consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) for interim financial information, the 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 GAAP for complete financial statements and should be read in conjunction with the Company’s audited financial statements and notes thereto included in its Annual Report on Form 10-K for the year ended December 31, 2020. In the opinion of the Company’s management, all adjustments, consisting of normal recurring adjustments, necessary for a fair presentation of its financial position, operating results and cash flows for the periods presented have been included. Operating results for the three and nine months ended September 30, 2021 are not necessarily indicative of the results that may be expected for the full year, for any other interim period or for any future year.

Fair Value of Financial Instruments

The carrying amounts of certain financial instruments, including accounts receivable, accounts payable and accrued expenses approximate their fair values due to the short-term nature of such instruments.

For assets and liabilities recorded at fair value, it is the Company’s policy to maximize the use of observable inputs and minimize the use of unobservable inputs when developing fair value measurements, in accordance with the fair value hierarchy. Fair value measurements for assets and liabilities where there exists limited or no observable market data are based primarily upon estimates and are often calculated based on the economic and competitive environment, the characteristics of the asset or liability and other factors. Therefore, fair value measurements cannot be determined with precision and may not be realized in an actual sale or immediate settlement of the asset or liability. Additionally, there may be inherent weaknesses in any calculation technique and changes in the underlying assumptions used, including discount rates and estimates of future cash flows, could significantly affect the calculated current or future fair values. The Company utilizes fair value measurements to record fair value adjustments to certain assets and liabilities and to determine fair value disclosures.

The Company groups assets and liabilities at fair value in three levels, based on the markets in which the assets and liabilities are traded and the reliability of the assumptions used to determine fair value. The determination of where an asset or liability falls in the hierarchy requires significant judgment. These levels are:

•Level 1 — Valuations based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access.

•Level 2 — Valuations based on quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, and models for which all significant inputs are observable, either directly or indirectly.

•Level 3 — Valuations based on inputs that are unobservable and significant to the overall fair value measurement.

At September 30, 2021 and December 31, 2020, the Company had cash equivalents including money market funds, whose value is based on quoted market prices. At September 30, 2021 and December 31, 2020, the Company had short-term investments, including U.S. Treasury securities, whose value is based on quoted market prices. At September 30, 2021, the Company had long-term investments including U.S. Treasury securities, whose value is based on quoted market prices. Accordingly, these securities are classified as Level 1.

At September 30, 2021, the Company had short-term investments, including commercial paper, and corporate bonds, and on December 31, 2020, the Company had short-term investments including corporate bonds. As quoted prices are not available for these securities, they are valued using independent pricing models or other model-based valuation techniques such as the present value of future cash flows, adjusted for the security’s credit rating, prepayment assumptions and other factors such as credit loss assumptions. Accordingly, these securities are classified as Level 2.

There was no material re-measurement to fair value of financial assets and liabilities that are not measured at fair value on a recurring basis. For additional information regarding the Company's investments, please refer to Note 2, "Investments."

Below are tables that present information about certain assets measured at fair value on a recurring basis (in thousands):


	Fair Value Measurements
	September 30, 2021
	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash equivalents
Money market funds	$	20,165	$	20,165	$	—	$	—




Total cash equivalents	20,165		20,165		—		—
Short-term investments

U.S. treasury securities	7,534		7,534		—		—

Commercial paper	51,277		—		51,277		—
Corporate bonds	37,573		—		37,573		—
Total short-term investments	96,384		7,534		88,850		—
Long-term investments

U.S. treasury securities	2,035		2,035		—		—
Total long-term investments	2,035		2,035		—		—
Total assets	$	118,584	$	29,734	$	88,850	$	—

	Fair Value Measurements
	December 31, 2020
	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash equivalents
Money market funds	$	1,503	$	1,503	$	—	$	—



Total cash equivalents	1,503		1,503		—		—
Short-term investments

U.S. treasury securities	28,715		28,715		—		—


Corporate bonds	3,258		—		3,258		—
Total short-term investments	31,973		28,715		3,258		—





Total assets	$	33,476	$	30,218	$	3,258	$	—

Inventories

The Company considers regulatory approval of product candidates to be uncertain and product manufactured prior to regulatory approval may not be sold unless regulatory approval is obtained. As such, the manufacturing costs for product candidates incurred prior to regulatory approval are not capitalized as inventory but are expensed as research and development costs. The Company begins capitalization of these inventory related costs once regulatory approval is obtained. The Company primarily uses actual costs to determine its cost basis for inventories.

At September 30, 2021, the Company’s inventory is related to TEMBEXA, which is being manufactured for the treatment of smallpox and potential delivery to the Strategic National Stockpile (SNS) for the U.S. government and other government agencies. TEMBEXA was approved by the FDA on June 4, 2021, at which time the Company began to capitalize inventory costs associated with TEMBEXA. Prior to FDA approval of TEMBEXA, all costs related to the manufacturing of TEMBEXA were charged to research and development expense in the period incurred as there was no alternative future use.

The Company values its inventories at the lower of cost or estimated net realizable value. The Company determines the cost of its inventories, which includes amounts related to materials, manufacturing costs, shipping and handling costs on a first-in, first-out (FIFO) basis. Work-in-process includes all inventory costs prior to packaging and labelling, including raw material, active product ingredient, and drug product. Finished goods include packaged and labelled products. The Company's inventories at September 30, 2021 consisted of $1.6 million of work-in-process and no finished goods.

The Company’s assessment of market value requires the use of estimates regarding the net realizable value of its inventory balances, including an assessment of excess or obsolete inventory. The Company’s determination that a valuation reserve might be required, in addition to the quantification of such reserve, requires it to utilize significant judgment. The Company determines excess or obsolete inventory based on multiple factors, including an estimate of the future demand for its products, product expiration dates and current sales levels. The Company’s assumptions of future demand for its products are inherently uncertain and if the Company were to change any of these judgments or estimates, it could cause a material increase or decrease in the amount of inventory reserves that the Company reports in a particular period. In addition, the Company's inventory may experience expiration of its shelf-life stability. During the nine months ended September 30, 2021, the Company did not record a reserve for inventory as the Company assumes TEMBEXA will be sold to the US government under a procurement contract with Biomedical Advanced Research and Development Authority (BARDA) or could be sold to other governmental agencies. Should no procurement contract be secured in the future, the Company may reserve part or all of our inventory balance, which would be included in cost of sales.

Accrued Liabilities

Accrued liabilities consisted of the following (in thousands):


	September 30, 2021		December 31, 2020
Accrued research and development expenses	$	3,276	$	1,375
Accrued compensation	4,502		4,473
Accrued legal expenses	213		651
Other accrued liabilities	2,507		751

Total accrued liabilities	$	10,498	$	7,250

Revenue Recognition

Policy

The Company’s revenues generally consist of (i) contract and grant revenue - revenue generated under federal and private foundation grants and contracts, and (ii) collaboration and licensing revenue - revenue related to non-refundable upfront fees, royalties and milestone payments earned under license agreements. Revenue is recognized in accordance with the criteria outlined in Accounting Standards Codification (ASC) 606 issued by the Financial Accounting Standards Board (FASB). Following this accounting pronouncement, a five-step approach is applied for recognizing revenue, including (1) identify the contract with a customer; (2) identify the performance obligations in the contract; (3) determine the transaction price; (4) allocate the transaction price to the performance obligations in the contract; and (5) recognize revenue when, or as, the entity satisfies a performance obligation.

Biomedical Advanced Research and Development Authority (BARDA)

In February 2011, the Company entered into a contract with BARDA for the advanced development of TEMBEXA as a medical countermeasure in the event of a smallpox release. Under the contract, the Company received $72.5 million in expense reimbursement and $4.6 million in fees over the performance of one base segment and four option segments. Exercise of each option segment was solely at the discretion of BARDA. The Company assessed the services in accordance with the authoritative guidance and concluded that there was a potential of five separate contracts (one base segment and four option segments) within this agreement, each of which had a single performance obligation. All option segments (one through four) were exercised, as well as the base segment. The transaction price for each segment, based on the transaction price as defined in

each segment contract, was allocated to the single performance obligation for each contract. The transaction price was recognized over time by measuring the progress toward complete satisfaction of the performance obligation. For reimbursable expenses, this occurred as qualifying research activities were conducted based on invoices from company vendors. For the fixed fee, the progress toward complete satisfaction was estimated based on the costs incurred to date relative to the total estimated costs per the terms of each contract. The Company typically invoiced BARDA monthly as costs were incurred. Any amounts received in advance of performance were recorded as deferred revenue until earned. The base segment and first option segment were completed prior to adoption of ASC 606. The second and third option segments were completed on August 20, 2020. The fourth option segment was completed on September 1, 2021 and the contract has expired in accordance with its terms.

Grant Revenue

Grant revenue under cost-plus-fixed-fee grants from the federal government and private foundations is recognized as allowable costs are incurred and fees are earned. As a result of its acquisition of Oncoceutics, Inc. (Oncoceutics), the Company became the beneficiary of two federal grant programs and two grant programs with private foundations, of which the federal grant programs ended in the third quarter of 2021. At September 30, 2021, the Company has a deferred revenue balance of $0.2 million related to these grants. Additionally, for the three and nine months ended September 30, 2021, the Company recognized $18,000 and $0.4 million of grant revenue related to these grants, respectively.

SymBio Pharmaceuticals

On September 30, 2019, the Company entered into a license agreement with SymBio Pharmaceuticals Limited (SymBio) under which the Company granted SymBio exclusive worldwide rights to develop, manufacture and commercialize TEMBEXA for all human indications, excluding the prevention and treatment of orthopoxviruses, including smallpox. The Company assessed the agreement in accordance with the authoritative guidance and concluded that the SymBio contract includes multiple performance obligations. The SymBio contract has one fixed transaction amount of a $5.0 million upfront payment received in October 2019 and several variable transaction amounts, up to $180 million, due to the Company at certain regulatory and commercial milestones, along with low double-digit percent royalties based on net sales of TEMBEXA. All variable transaction amounts are fully constrained, therefore the allocated transaction price is $5.0 million. The majority of the transaction price of the contract has been allocated to the combined performance obligation of the granting of the license to TEMBEXA and associated technology transfer which was recognized when the technology transfer was completed in the fourth quarter of 2019. The revenue from regulatory and commercial milestones and royalties from net sales will be recognized upon the occurrence of the triggering events or when those transaction amounts are no longer fully constrained.

Research and Development Prepaids and Accruals

As part of the process of preparing financial statements, the Company is required to estimate its expenses resulting from its obligation under contracts with vendors and consultants and clinical site agreements in connection with its research and development efforts. The financial terms of these contracts are subject to negotiations which vary contract to contract and may result in payment flows that do not match the periods over which materials or services are provided to the Company under such contracts.

The Company’s objective is to reflect the appropriate research and development expenses in its financial statements by matching those expenses with the period in which services and efforts are expended. The Company accounts for these expenses according to the progress of its research and development efforts. The Company determines prepaid and accrual estimates through discussion with applicable personnel and outside service providers as to the progress or state of communication of clinical trials, or other services completed. The Company adjusts its rate of research and development expense recognition if actual results differ from its estimates. The Company makes estimates of its prepaid and accrued expenses as of each balance sheet date in its financial statements based on facts and circumstances known at that time. Although the Company does not expect its estimates to be materially different from amounts actually incurred, its understanding of status and timing of services performed relative to the actual status and timing of services performed may vary and may result in the Company reporting amounts that are too high or too low for any particular period. Through September 30, 2021, there had been no material adjustments to the Company’s prior period estimates of prepaid and accruals for research and development expenses. The Company’s research and development prepaids and accruals are dependent upon the timely and accurate reporting of contract research organizations and other third-party vendors.

Basic and Diluted Net Loss Per Share of Common Stock

Basic net loss per share of common stock is computed by dividing net loss by the weighted-average number of shares of common stock outstanding during the period, excluding the dilutive effects of non-vested restricted stock, stock options, and employee stock purchase plan purchase rights. Diluted net loss per share of common stock is computed by dividing net loss by

the sum of the weighted-average number of shares of common stock outstanding during the period plus the potential dilutive effects of non-vested restricted stock, stock options, and employee stock purchase plan purchase rights outstanding during the period calculated in accordance with the treasury stock method, but are excluded if their effect is anti-dilutive. Because the impact of these items is anti-dilutive during the periods of net loss, there was no difference between basic and diluted loss per share of common stock for the three and nine months ended September 30, 2021 and 2020.

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, and related disclosure of contingent assets and liabilities. In addition to estimates discussed in other sections of this Quarterly Report on Form 10-Q, the most significant estimates in the Company’s consolidated financial statements relate to the valuation of stock options and the valuation allowance for deferred tax assets resulting from net operating losses. These estimates are based on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results could differ from those estimates.

Segments

The Company operates in only one segment, pharmaceuticals.

Impact of Recently Issued Accounting Standards

In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which amends the impairment model by requiring entities to use a forward-looking approach on expected losses to estimate credit losses on certain financial instruments, including trade receivables and available-for-sale debt securities. The new guidance was originally due to become effective for the Company beginning in the first quarter of 2020, however the FASB in November 2019 issued ASU 2019-10 which moved the effective date for smaller reporting companies to the first quarter of 2023. The Company is currently evaluating the potential impact that this standard may have on its consolidated financial statements.

Investments

9 Months Ended

Sep. 30, 2021

Investments, Debt and Equity Securities [Abstract]

Investments

The following tables summarize the Company's debt investments (in thousands):


	September 30, 2021
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Corporate bonds	$	37,579	$	1	$	(7)	$	37,573

U.S. treasury securities	9,568		2		(1)		9,569
Commercial paper	51,272		7		(2)		51,277

Total investments	$	98,419	$	10	$	(10)	$	98,419

	December 31, 2020
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Corporate bonds	$	3,256	$	2	$	—	$	3,258


U.S. treasury securities	28,717		1		(3)		28,715

Total investments	$	31,973	$	3	$	(3)	$	31,973

The following tables summarize the Company's debt investments with unrealized losses, aggregated by investment type and the length of time that individual investments have been in a continuous unrealized loss position (in thousands, except number of securities):


	September 30, 2021
	Less than 12 Months				Greater than 12 Months				Total
	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Corporate bonds	$	27,554	$	(7)	$	—	$	—	$	27,554	$	(7)
Commercial paper	10,491		(2)		—		—		10,491		(2)
U.S. treasury securities	7,034		(1)		—		—		7,034		(1)

Total	$	45,079	$	(10)	$	—	$	—	$	45,079	$	(10)
Number of securities with unrealized losses			16				—				16

	December 31, 2020
	Less than 12 Months				Greater than 12 Months				Total
	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss



U.S. treasury securities	$	16,598	$	(3)	$	—	$	—	$	16,598	$	(3)

Total	$	16,598	$	(3)	$	—	$	—	$	16,598	$	(3)
Number of securities with unrealized losses			6				—				6

The Company periodically reviews available-for-sale debt investments for other-than-temporary declines in fair value below the cost basis and whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. The Company evaluates, among other things, the duration and extent to which the fair value of a security is less than its cost; the financial condition of the issuer and any changes thereto; and the Company’s intent to sell, or whether it will more likely than not be required to sell, the security before recovery of its cost basis. At September 30, 2021, the Company did not intend to sell, and was not more likely than not to be required to sell, the available-for-sale debt investments in an unrealized loss position before recovery of the cost basis of the securities, which may be at maturity. There were no such declines in value for the three and nine months ended September 30, 2021 and 2020. Unrealized gains and losses on debt investments are recorded to unrealized (loss) gain on debt investments, net in the Consolidated Statements of Operations and Comprehensive Loss. Realized gains and losses on debt investments are recorded based on specific identification to interest income and other, net in the Consolidated Statements of Operations and Comprehensive Loss. The Company recognizes interest income on an accrual basis in interest income in the Consolidated Statements of Operations and Comprehensive Loss.

The following table summarizes the scheduled maturity for the Company's debt investments at September 30, 2021 (in thousands):


Maturing in one year or less	$	96,384
Maturing after one year through two years	2,035
Total debt investments	$	98,419

Commitments and Contingencies

9 Months Ended

Sep. 30, 2021

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

Leases

The Company leases its facilities under long-term operating leases that expire at various dates through 2026. The Company generally has options to renew lease terms on its facilities, which may be exercised at the Company's sole discretion. In addition, certain lease arrangements may be terminated prior to their original expiration date at the Company's discretion. The Company evaluates renewal and termination options at the lease commencement date to determine if it is reasonably certain to exercise the option and has concluded on all operating leases that it is not reasonably certain that any options will be exercised. The weighted-average remaining lease term for the Company's operating leases as of September 30, 2021 was 4.84 years.

Expense related to leases is recorded on a straight-line basis over the lease term. Lease expense under operating leases, including common area maintenance fees, totaled approximately $0.2 million and $0.2 million, respectively, for the three months ended September 30, 2021 and 2020 and approximately $0.5 million and $0.6 million for the nine months ended September 30, 2021 and 2020, respectively.

The discount rate implicit within the Company's leases is generally not determinable and therefore the Company determines the discount rate based on its incremental borrowing rate based on the information available at commencement date. As of September 30, 2021, the operating lease liabilities reflect a weighted-average discount rate of 7.89%.

The following table sets forth the operating lease right-of-use assets and liabilities as of September 30, 2021 (in thousands):


Assets
Operating lease right-of-use assets	$	2,509

Liabilities
Operating lease short-term liabilities (recorded within Accrued liabilities)	$	416
Operating lease long-term liabilities (recorded within Lease-related obligations)	2,525
Total operating lease liabilities	$	2,941

Operating lease payments over the remainder of the lease terms are as follows (in thousands):


Years Ending December 31,	As of September 30, 2021
2021 (1)	$	97
2022	715
2023	736
2024	759
2025	781
All remaining years	467
Total future minimum rental payments	$	3,555
Less amount of lease payments representing interest	614
Total present value of lease payments	$	2,941

(1)The Company entered into the Ninth Amendment of its lease for the Company's headquarters in Durham, North Carolina, which extended the term of the lease by 65 months to July 31, 2026. As part of the amendment, the Company is entitled to receive a rent abatement of the first five months of the new lease term which began on March 1, 2021. Additionally, the Ninth Amendment grants the Company a refurbishment allowance, which the Company expects to receive in 2021 after the refurbishment has been completed.

As of December 31, 2020, operating lease payments over the remainder of the lease terms were as follows (in thousands):


Years Ending December 31,	As of December 31, 2020

2021	$	260
2022	715
2023	736
2024	759
2025	781
Thereafter	467
Total future minimum rental payments	$	3,718
Less amount of lease payments representing interest	792
Total present value of lease payments	$	2,926

For the three months ended September 30, 2021 and 2020, the Company made lease payments of approximately $122,000 and $181,000, respectively, and for the nine months ended September 30, 2021 and 2020, the Company made lease payments of approximately $292,000 and $538,000, respectively.

Sublease

The Company subleased 3,537 square feet of its office space under a non-cancelable operating lease that expired in February 2021. For the three and nine months ended September 30, 2021, the Company recognized $0 and approximately $12,000 of income, respectively, and for the three and nine months ended September 30, 2020, the Company recognized approximately $18,000 and $53,000 of income, respectively, in Interest income and other, net on the Consolidated Statement of Operations and Comprehensive Loss. As this lease has terminated, there are no future minimum rentals payments to be received.

Significance of Revenue Source

The Company is the recipient of federal research contract funds from BARDA, the primary source of the Company's contract and grant revenue. Periodic audits are required under the Company’s BARDA agreement and certain costs may be questioned as appropriate under the BARDA agreement. At September 30, 2021 and December 31, 2020, the Company had recorded a provision for potential refundable amounts of $52,000 and $38,000, respectively.

Equity Transactions and Share-based Compensation

9 Months Ended

Sep. 30, 2021

Share-based Payment Arrangement [Abstract]

Equity Transactions and Share-based Compensation

Common Stock

On January 20, 2021, the Company entered into an underwriting agreement (the Underwriting Agreement) with Jefferies LLC and Cowen and Company, LLC, as representatives of the several underwriters named therein (collectively, the Underwriters), relating to the issuance and sale of 11,765,000 shares (the Shares) of the Company’s common stock, par value $0.001 per share (the Common Stock). The price to the public in this offering was $8.50 per share, and the Underwriters agreed to purchase the Shares from the Company pursuant to the Underwriting Agreement at a price of $7.99 per share. Under the terms of the Underwriting Agreement, the Company granted the Underwriters a 30-day option to purchase up to 1,764,750 additional shares of Common Stock at the public offering price. The net proceeds to the Company from this offering were approximately $107.8 million, as the Underwriters’ option to purchase additional shares was exercised in full, after deducting underwriting discounts and commissions and estimated offering expenses payable by the Company. The offering closed on January 25, 2021.

Stock Options

The Company maintains a 2013 Equity Incentive Plan (the 2013 Plan), which provides for the grant of incentive stock options (ISOs), non-statutory stock options (NSOs), stock appreciation rights, restricted stock awards, restricted stock unit (RSU) awards, performance-based stock awards, and other forms of equity compensation (collectively, stock awards), all of which may be granted to employees, including officers, non-employee directors and consultants of the Company and its affiliates. Additionally, the 2013 Plan provides for the grant of performance cash awards. The number of shares of common stock reserved for future issuance automatically increases on January 1 of each calendar year by 4% of the total number of shares of capital stock outstanding on December 31 of the preceding calendar year, or a lesser number of shares determined by the Company’s board of directors. On January 1, 2021, the common stock reserved for issuance under the 2013 Plan was automatically increased by 2.5 million shares. As of September 30, 2021, there was a total of 2.2 million shares reserved for future issuance under the 2013 Plan. The Company issued approximately 75,000 and 826,000 shares of common stock pursuant to the exercise of stock options during the three and nine months ended September 30, 2021, respectively. The Company issued 21,000 and 263,000 shares of common stock pursuant to the exercise of stock options during the three and nine months ended September 30, 2020, respectively.

Employee Stock Purchase Plan

The Company maintains a 2013 Employee Stock Purchase Plan (ESPP), which provides for the issuance of shares of common stock pursuant to purchase rights granted to the Company’s employees or to employees of any of its designated affiliates. The Company has reserved a total of 3.9 million shares of common stock to be purchased under the ESPP, of which 2.3 million shares remained available for purchase as of September 30, 2021. The number of shares of common stock reserved for issuance automatically increases on January 1 of each calendar year, by the lesser of (a) 1% of the total number of shares of common stock outstanding on December 31 of the preceding calendar year, (b) 422,535 shares, or (c) a number determined by the Company’s board of directors that is less than (a) and (b). On January 1, 2021, the common stock reserved for issuance under the ESPP was automatically increased by an additional 422,535 shares.

The ESPP provides for an automatic reset feature to start participants on a new twenty-four month participation period in the event that the common stock market value on a purchase date is less than the common stock value on the first day of the twenty-four month offering period. Eligible employees may authorize an amount up to 15% of their salary to purchase common stock at the lower of a 15% discount to the beginning price of their offering period or a 15% discount to the ending price of

each six-month purchase interval. The Company issued approximately 283,000 and 160,000 shares of common stock pursuant to the ESPP during the three months ended September 30, 2021 and 2020, respectively. The Company issued approximately 543,000 and 337,000 shares of common stock pursuant to the ESPP during the nine months ended September 30, 2021 and 2020, respectively. Compensation expense for shares purchased under the ESPP related to the purchase discount and the “look-back” option and were determined using a Black-Scholes option pricing model.

Restricted Stock Units

The Company has issued RSUs to certain employees which vest based on service criteria. When vested, the RSU represents the right to be issued the number of shares of the Company's common stock that is equal to the number of RSUs granted. The grant date fair value for RSUs is based upon the market price of the Company's common stock on the date of the grant. The fair value is then amortized to compensation expense over the requisite service period or vesting term. The Company issued 241,000 shares and approximately 410,000 shares of common stock pursuant to the vesting of RSUs during the three and nine months ended September 30, 2021, respectively. The Company issued 277,000 shares and approximately 440,000 shares of common stock pursuant to the vesting of RSUs during the three and nine months ended September 30, 2020, respectively.

Stock-based Compensation

For awards with only service conditions and graded-vesting features, the Company recognizes compensation expense on a straight-line basis over the requisite service period. Total share-based compensation expense recognized related to stock options, the ESPP and RSUs was as follows (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Research and development expense	$	1,853	$	625	$	4,995	$	2,090
General and administrative expense	1,578		657		4,132		1,910
Total share-based compensation expense	$	3,431	$	1,282	$	9,127	$	4,000

Income Taxes	9 Months Ended
Income Taxes	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company estimates an annual effective tax rate of 0% for the year ending December 31, 2021 as the Company incurred losses for the nine month period ended September 30, 2021, and is forecasting an estimated net loss for both financial statement and tax purposes for the year ending December 31, 2021. Therefore, no federal or state income taxes are expected and none have been recorded at this time. Income taxes have been accounted for using the liability method in accordance with FASB ASC 740. Due to the Company's history of losses since inception, there is not enough evidence at this time to support that the Company will generate future income of a sufficient amount and nature to utilize the benefits of its net deferred tax assets. Accordingly, the deferred tax assets have been reduced by a full valuation allowance, since the Company cannot currently support that realization of its deferred tax assets is more likely than not. However, the Company feels its deferred tax assets may be used upon the Company becoming profitable. At September 30, 2021, the Company had no unrecognized tax benefits that would reduce the Company’s effective tax rate if recognized.

- 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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 21
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32857-109319

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-URI http://asc.fasb.org/extlink&oid=122134291&loc=d3e330215-122817

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 17
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32809-109319

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-URI http://asc.fasb.org/extlink&oid=122134291&loc=d3e330036-122817

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32705-109319

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 270
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6424409&loc=d3e44925-109338

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-URI http://asc.fasb.org/topic&trid=2144680

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6424122&loc=d3e41874-109331

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

Significant Agreements	9 Months Ended
Significant Agreements	Sep. 30, 2021
Revenue Recognition [Abstract]
Significant Agreements	Significant Agreements Biomedical Advanced Research and Development Authority (BARDA) In February 2011, the Company entered into a contract with BARDA for the advanced development of TEMBEXA as a medical countermeasure in the event of a smallpox release. Under the contract, BARDA agreed to reimburse the Company, plus pay a fixed fee, for the research and development of TEMBEXA as a broad-spectrum therapeutic antiviral for the treatment of smallpox infections. The contract consists of an initial performance period, referred to as the base performance segment, plus up to four extension periods, referred to as option segments, of which all have been exercised. Under the contract, the Company received $72.5 million in expense reimbursement and $4.6 million in fees. The fourth option segment ended on September 1, 2021 and the contract has expired in accordance with its terms. For the three months ended September 30, 2021 and 2020, the Company recognized revenue under this contract of $0.1 million and $1.6 million, respectively, and for the nine months ended September 30, 2021 and 2020, the Company recognized revenue under this contract of $1.6 million and $4.2 million, respectively. Cantex Pharmaceuticals, Inc. In July 2019, the Company entered into a License and Development Agreement with Cantex Pharmaceuticals, Inc. (Cantex) pursuant to which the Company acquired exclusive worldwide rights to develop and commercialize, for any and all uses, a glycosaminoglycan compound known as DSTAT, which is currently being studied for the treatment of acute myeloid leukemia. Under the terms of the license agreement, the Company is responsible for, and bears the future costs of, worldwide development and commercialization of DSTAT. In connection with the transaction, Cantex assigned to the Company all of its rights under its DSTAT supply agreements, including its bulk API agreement with Scientific Protein Laboratories LLC (SPL), including subsequent amendments, pursuant to which SPL will exclusively produce DSTAT for the Company through December 2040. The license agreement obligates the Company to pay Cantex regulatory milestone payments of up to $202.5 million upon receipt of product approvals in the United States, the European Union and Japan, and sales milestone payments of up to $385.0 million upon achievement of specified net sales levels. The Company also agreed to pay Cantex tiered royalties based on percentages of net sales beginning at 10% and not to exceed the high-teens. SymBio Pharmaceuticals On September 30, 2019, the Company entered into a license agreement with SymBio under which the Company granted SymBio exclusive worldwide rights to develop, manufacture and commercialize TEMBEXA for all human indications, excluding the prevention and treatment of orthopoxviruses, including smallpox. Under the terms of the license agreement, SymBio will be responsible for, and bear the future costs of, worldwide development and commercialization of TEMBEXA in the licensed indications. Either party may terminate the license agreement upon the occurrence of a material breach by the other party (subject to standard cure periods). SymBio may also terminate the license agreement without cause on a country-by-country basis upon ninety days' prior notice. In exchange for the license to SymBio under the Company's TEMBEXA rights, the Company received an upfront payment of $5.0 million in October 2019. In addition, the Company is eligible to receive up to $180.0 million in clinical, regulatory and commercial milestones worldwide, as well as low double-digit percent royalties based on net sales of TEMBEXA. Since entering into the license agreement in September 2019, the Company has recognized all of the $5.0 million upfront payment. Ohara Agreement In 2019, Oncoceutics, Inc., a Delaware corporation (Oncoceutics) entered into a license, development and commercialization agreement with Ohara Pharmaceutical Co., Ltd. for ONC201 in Japan. The Company is entitled to receive up to $2.5 million in nonrefundable regulatory milestone payments. The Company is entitled to tiered royalties based on the aggregate annual net sales of all products, as defined in the agreement, in Japan. CR Sanjiu Agreement In December 2020, Oncoceutics entered into a license, development and commercialization agreement with China Resources Sanjiu Medical & Pharmaceutical Co., Ltd. (CR Sanjiu). Oncoceutics granted CR Sanjiu an exclusive royalty bearing license to develop and commercialize ONC201 in China, Hong Kong, Macau and Taiwan (CR Sanjiu Territory). The Company is entitled to receive up to $5.0 million in nonrefundable regulatory milestone payments. The Company is entitled to tiered royalties based on the aggregate annual net sales of all licensed products, as defined in the agreement, in China.

Oncoceutics Acquisition

9 Months Ended

Sep. 30, 2021

Business Combination and Asset Acquisition [Abstract]

Oncoceutics Acquisition

Oncoceutics AcquisitionOn January 7, 2021, the Company, Ocean Merger Sub, Inc., a Delaware corporation and wholly-owned subsidiary of the Company (Merger Sub), Oncoceutics and Fortis Advisors, LLC solely in its capacity as representative of the securityholders of Oncoceutics (the Securityholders’ Representative), entered into an Agreement and Plan of Merger (the Merger Agreement). Concurrently with the execution of the Merger Agreement, Merger Sub merged with and into Oncoceutics (the Merger) whereupon the separate corporate existence of Merger Sub ceased, with Oncoceutics continuing as the surviving corporation of the Merger as a wholly-owned subsidiary of the Company.

As consideration for the Merger, the Company (a) paid an upfront cash payment of approximately $25.0 million, subject to certain customary adjustments, (b) issued an aggregate of 8,723,769 shares of the Company's common stock, (c) issued a promissory note to the Securityholders' Representative in the principal amount of $14.0 million (the Seller Note), to be paid in cash, subject to the terms and conditions of the Merger Agreement and the Seller Note, upon the one year anniversary of the closing of the Merger, and (d) agreed to make contingent payments up to an aggregate of $360.0 million based on the achievement of certain development, regulatory and commercialization events as set forth in the Merger Agreement, as well as additional tiered royalty payments based upon future net sales of ONC 201 and ONC 206 products, subject to certain reductions as set forth in the Merger Agreement, and a contingent payment in the event the Company receives any proceeds from the sale of a rare pediatric disease priority review voucher based on Oncoceutics' products. The closing payment may be adjusted after the closing, pursuant to procedures set forth in the Merger Agreement, in connection with the finalization of the cash, transaction expenses, debt and working capital amounts at closing. As of September 30, 2021, the Company has recorded an estimated liability of $0.2 million related to closing payment adjustments. Additionally, as of September 30, 2021, the Company has recorded an estimated receivable of $0.6 million related to the repayment of certain severance amounts due from the Oncoceutics' shareholders.

The Company accounted for the Oncoceutics acquisition as an asset acquisition as the majority of the value of the assets acquired related to the ONC201 acquired in-process research and development (IPR&D) asset. In accordance with Accounting Standards Codification (ASC) Subtopic 730-10-25, Accounting for Research and Development Costs, the up-front payments to acquire a new drug compound, as well as future milestone payments when paid or payable, are immediately expensed as acquired IPR&D in transactions other than a business combination provided that the drug has not achieved regulatory approval for marketing and, absent obtaining such approval, has no alternative future use. Therefore, the portion of the purchase price that was allocated to the IPR&D assets acquired was immediately expensed. Other assets acquired and liabilities assumed, were recorded at fair value.

The following represents the consideration paid and purchase price allocation for the acquisition of Oncoceutics (in thousands, except for per share data):


Cash	$	23,836
One-year closing anniversary payment	14,000

Shares common stock issued as consideration	8,723,769
Stock price per share on effective date	4.98
Value of estimated common stock consideration	43,445
Total consideration	$	81,281

Net assets acquired	$	(1,310)
IPR&D assets expensed	82,591
Total purchase price allocated	$	81,281

Transaction costs expensed to IPR&D(1)	$	299
Total IPR&D expensed	$	82,890

(1) As a result of the asset acquisition accounting, the transaction costs associated with the acquisition should be included in the costs of the assets acquired. The primary asset acquired, the IPR&D asset, was expensed and the transaction related costs were included with and expensed with this asset. The transaction costs primarily included financial advisor fees, legal expenses and auditor expenses. Additionally, there were $0.6 million of expenses related to this acquisition recorded in the fourth quarter of 2020 to general and administrative expenses in the Consolidated Statements of Operations and Comprehensive Loss.

Subsequent Events	9 Months Ended
Subsequent Events	Sep. 30, 2021
Subsequent Events [Abstract]
Subsequent Events	Subsequent EventsThe Company has evaluated subsequent events through the issuance date of these financial statements to ensure that this filing includes appropriate disclosure of events both recognized in the financial statements as of September 30, 2021, and events which occurred subsequently but were not recognized in the financial statements.In accordance with the terms of the merger agreement between Chimerix and Oncoceutics, Inc., the achievement of the 20% overall response rate (ORR) via Blinded Independent Central Review (BICR) will result in a success milestone payment of $20 million to the former Oncoceutics, Inc. shareholders to be paid prior to year-end.

The Business and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of PresentationThe accompanying unaudited consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. The accompanying unaudited consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) for interim financial information, the 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 GAAP for complete financial statements and should be read in conjunction with the Company’s audited financial statements and notes thereto included in its Annual Report on Form 10-K for the year ended December 31, 2020. In the opinion of the Company’s management, all adjustments, consisting of normal recurring adjustments, necessary for a fair presentation of its financial position, operating results and cash flows for the periods presented have been included. Operating results for the three and nine months ended September 30, 2021 are not necessarily indicative of the results that may be expected for the full year, for any other interim period or for any future year.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The carrying amounts of certain financial instruments, including accounts receivable, accounts payable and accrued expenses approximate their fair values due to the short-term nature of such instruments. For assets and liabilities recorded at fair value, it is the Company’s policy to maximize the use of observable inputs and minimize the use of unobservable inputs when developing fair value measurements, in accordance with the fair value hierarchy. Fair value measurements for assets and liabilities where there exists limited or no observable market data are based primarily upon estimates and are often calculated based on the economic and competitive environment, the characteristics of the asset or liability and other factors. Therefore, fair value measurements cannot be determined with precision and may not be realized in an actual sale or immediate settlement of the asset or liability. Additionally, there may be inherent weaknesses in any calculation technique and changes in the underlying assumptions used, including discount rates and estimates of future cash flows, could significantly affect the calculated current or future fair values. The Company utilizes fair value measurements to record fair value adjustments to certain assets and liabilities and to determine fair value disclosures. The Company groups assets and liabilities at fair value in three levels, based on the markets in which the assets and liabilities are traded and the reliability of the assumptions used to determine fair value. The determination of where an asset or liability falls in the hierarchy requires significant judgment. These levels are: •Level 1 — Valuations based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access. •Level 2 — Valuations based on quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, and models for which all significant inputs are observable, either directly or indirectly. •Level 3 — Valuations based on inputs that are unobservable and significant to the overall fair value measurement. At September 30, 2021 and December 31, 2020, the Company had cash equivalents including money market funds, whose value is based on quoted market prices. At September 30, 2021 and December 31, 2020, the Company had short-term investments, including U.S. Treasury securities, whose value is based on quoted market prices. At September 30, 2021, the Company had long-term investments including U.S. Treasury securities, whose value is based on quoted market prices. Accordingly, these securities are classified as Level 1. At September 30, 2021, the Company had short-term investments, including commercial paper, and corporate bonds, and on December 31, 2020, the Company had short-term investments including corporate bonds. As quoted prices are not available for these securities, they are valued using independent pricing models or other model-based valuation techniques such as the present value of future cash flows, adjusted for the security’s credit rating, prepayment assumptions and other factors such as credit loss assumptions. Accordingly, these securities are classified as Level 2. There was no material re-measurement to fair value of financial assets and liabilities that are not measured at fair value on a recurring basis. For additional information regarding the Company's investments, please refer to Note 2, "Investments."
Inventories	Inventories The Company considers regulatory approval of product candidates to be uncertain and product manufactured prior to regulatory approval may not be sold unless regulatory approval is obtained. As such, the manufacturing costs for product candidates incurred prior to regulatory approval are not capitalized as inventory but are expensed as research and development costs. The Company begins capitalization of these inventory related costs once regulatory approval is obtained. The Company primarily uses actual costs to determine its cost basis for inventories. At September 30, 2021, the Company’s inventory is related to TEMBEXA, which is being manufactured for the treatment of smallpox and potential delivery to the Strategic National Stockpile (SNS) for the U.S. government and other government agencies. TEMBEXA was approved by the FDA on June 4, 2021, at which time the Company began to capitalize inventory costs associated with TEMBEXA. Prior to FDA approval of TEMBEXA, all costs related to the manufacturing of TEMBEXA were charged to research and development expense in the period incurred as there was no alternative future use. The Company values its inventories at the lower of cost or estimated net realizable value. The Company determines the cost of its inventories, which includes amounts related to materials, manufacturing costs, shipping and handling costs on a first-in, first-out (FIFO) basis. Work-in-process includes all inventory costs prior to packaging and labelling, including raw material, active product ingredient, and drug product. Finished goods include packaged and labelled products. The Company's inventories at September 30, 2021 consisted of $1.6 million of work-in-process and no finished goods. The Company’s assessment of market value requires the use of estimates regarding the net realizable value of its inventory balances, including an assessment of excess or obsolete inventory. The Company’s determination that a valuation reserve might be required, in addition to the quantification of such reserve, requires it to utilize significant judgment. The Company determines excess or obsolete inventory based on multiple factors, including an estimate of the future demand for its products, product expiration dates and current sales levels. The Company’s assumptions of future demand for its products are inherently uncertain and if the Company were to change any of these judgments or estimates, it could cause a material increase or decrease in the amount of inventory reserves that the Company reports in a particular period. In addition, the Company's inventory may experience expiration of its shelf-life stability. During the nine months ended September 30, 2021, the Company did not record a reserve for inventory as the Company assumes TEMBEXA will be sold to the US government under a procurement contract with Biomedical Advanced Research and Development Authority (BARDA) or could be sold to other governmental agencies. Should no procurement contract be secured in the future, the Company may reserve part or all of our inventory balance, which would be included in cost of sales.
Revenue Recognition	Revenue Recognition Policy The Company’s revenues generally consist of (i) contract and grant revenue - revenue generated under federal and private foundation grants and contracts, and (ii) collaboration and licensing revenue - revenue related to non-refundable upfront fees, royalties and milestone payments earned under license agreements. Revenue is recognized in accordance with the criteria outlined in Accounting Standards Codification (ASC) 606 issued by the Financial Accounting Standards Board (FASB). Following this accounting pronouncement, a five-step approach is applied for recognizing revenue, including (1) identify the contract with a customer; (2) identify the performance obligations in the contract; (3) determine the transaction price; (4) allocate the transaction price to the performance obligations in the contract; and (5) recognize revenue when, or as, the entity satisfies a performance obligation.
Research and Development Prepaids and Accruals	Research and Development Prepaids and Accruals As part of the process of preparing financial statements, the Company is required to estimate its expenses resulting from its obligation under contracts with vendors and consultants and clinical site agreements in connection with its research and development efforts. The financial terms of these contracts are subject to negotiations which vary contract to contract and may result in payment flows that do not match the periods over which materials or services are provided to the Company under such contracts. The Company’s objective is to reflect the appropriate research and development expenses in its financial statements by matching those expenses with the period in which services and efforts are expended. The Company accounts for these expenses according to the progress of its research and development efforts. The Company determines prepaid and accrual estimates through discussion with applicable personnel and outside service providers as to the progress or state of communication of clinical trials, or other services completed. The Company adjusts its rate of research and development expense recognition if actual results differ from its estimates. The Company makes estimates of its prepaid and accrued expenses as of each balance sheet date in its financial statements based on facts and circumstances known at that time. Although the Company does not expect its estimates to be materially different from amounts actually incurred, its understanding of status and timing of services performed relative to the actual status and timing of services performed may vary and may result in the Company reporting amounts that are too high or too low for any particular period. Through September 30, 2021, there had been no material adjustments to the Company’s prior period estimates of prepaid and accruals for research and development expenses. The Company’s research and development prepaids and accruals are dependent upon the timely and accurate reporting of contract research organizations and other third-party vendors.
Basic and Diluted Net Loss Per Share of Common Stock	Basic and Diluted Net Loss Per Share of Common Stock Basic net loss per share of common stock is computed by dividing net loss by the weighted-average number of shares of common stock outstanding during the period, excluding the dilutive effects of non-vested restricted stock, stock options, and employee stock purchase plan purchase rights. Diluted net loss per share of common stock is computed by dividing net loss by the sum of the weighted-average number of shares of common stock outstanding during the period plus the potential dilutive effects of non-vested restricted stock, stock options, and employee stock purchase plan purchase rights outstanding during the period calculated in accordance with the treasury stock method, but are excluded if their effect is anti-dilutive. Because the impact of these items is anti-dilutive during the periods of net loss, there was no difference between basic and diluted loss per share of common stock for the three and nine months ended September 30, 2021 and 2020.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, and related disclosure of contingent assets and liabilities. In addition to estimates discussed in other sections of this Quarterly Report on Form 10-Q, the most significant estimates in the Company’s consolidated financial statements relate to the valuation of stock options and the valuation allowance for deferred tax assets resulting from net operating losses. These estimates are based on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results could differ from those estimates.
Segments	SegmentsThe Company operates in only one segment, pharmaceuticals.
Impact of Recently Issued Accounting Standards	Impact of Recently Issued Accounting StandardsIn June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which amends the impairment model by requiring entities to use a forward-looking approach on expected losses to estimate credit losses on certain financial instruments, including trade receivables and available-for-sale debt securities. The new guidance was originally due to become effective for the Company beginning in the first quarter of 2020, however the FASB in November 2019 issued ASU 2019-10 which moved the effective date for smaller reporting companies to the first quarter of 2023. The Company is currently evaluating the potential impact that this standard may have on its consolidated financial statements.

The Business and Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2021

Accounting Policies [Abstract]

Schedule of certain assets measured at fair value on a recurring basis

Below are tables that present information about certain assets measured at fair value on a recurring basis (in thousands):


	Fair Value Measurements
	September 30, 2021
	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash equivalents
Money market funds	$	20,165	$	20,165	$	—	$	—




Total cash equivalents	20,165		20,165		—		—
Short-term investments

U.S. treasury securities	7,534		7,534		—		—

Commercial paper	51,277		—		51,277		—
Corporate bonds	37,573		—		37,573		—
Total short-term investments	96,384		7,534		88,850		—
Long-term investments

U.S. treasury securities	2,035		2,035		—		—
Total long-term investments	2,035		2,035		—		—
Total assets	$	118,584	$	29,734	$	88,850	$	—

	Fair Value Measurements
	December 31, 2020
	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash equivalents
Money market funds	$	1,503	$	1,503	$	—	$	—



Total cash equivalents	1,503		1,503		—		—
Short-term investments

U.S. treasury securities	28,715		28,715		—		—


Corporate bonds	3,258		—		3,258		—
Total short-term investments	31,973		28,715		3,258		—





Total assets	$	33,476	$	30,218	$	3,258	$	—

Schedule of accrued liabilities

Accrued liabilities consisted of the following (in thousands):


	September 30, 2021		December 31, 2020
Accrued research and development expenses	$	3,276	$	1,375
Accrued compensation	4,502		4,473
Accrued legal expenses	213		651
Other accrued liabilities	2,507		751

Total accrued liabilities	$	10,498	$	7,250

Investments (Tables)

9 Months Ended

Sep. 30, 2021

Investments, Debt and Equity Securities [Abstract]

Summary of short-term and long-term investments

The following tables summarize the Company's debt investments (in thousands):


	September 30, 2021
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Corporate bonds	$	37,579	$	1	$	(7)	$	37,573

U.S. treasury securities	9,568		2		(1)		9,569
Commercial paper	51,272		7		(2)		51,277

Total investments	$	98,419	$	10	$	(10)	$	98,419

	December 31, 2020
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Corporate bonds	$	3,256	$	2	$	—	$	3,258


U.S. treasury securities	28,717		1		(3)		28,715

Total investments	$	31,973	$	3	$	(3)	$	31,973

Summary of investments with unrealized losses, aggregated by investment type and the length of time


	September 30, 2021
	Less than 12 Months				Greater than 12 Months				Total
	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Corporate bonds	$	27,554	$	(7)	$	—	$	—	$	27,554	$	(7)
Commercial paper	10,491		(2)		—		—		10,491		(2)
U.S. treasury securities	7,034		(1)		—		—		7,034		(1)

Total	$	45,079	$	(10)	$	—	$	—	$	45,079	$	(10)
Number of securities with unrealized losses			16				—				16

	December 31, 2020
	Less than 12 Months				Greater than 12 Months				Total
	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss



U.S. treasury securities	$	16,598	$	(3)	$	—	$	—	$	16,598	$	(3)

Total	$	16,598	$	(3)	$	—	$	—	$	16,598	$	(3)
Number of securities with unrealized losses			6				—				6

Summary of the scheduled maturity of company investments

The following table summarizes the scheduled maturity for the Company's debt investments at September 30, 2021 (in thousands):


Maturing in one year or less	$	96,384
Maturing after one year through two years	2,035
Total debt investments	$	98,419

Commitments and Contingencies (Tables)

9 Months Ended

Sep. 30, 2021

Commitments and Contingencies Disclosure [Abstract]

Operating lease right-of-use assets and liabilities

The following table sets forth the operating lease right-of-use assets and liabilities as of September 30, 2021 (in thousands):


Assets
Operating lease right-of-use assets	$	2,509

Liabilities
Operating lease short-term liabilities (recorded within Accrued liabilities)	$	416
Operating lease long-term liabilities (recorded within Lease-related obligations)	2,525
Total operating lease liabilities	$	2,941

Operating lease maturity

Operating lease payments over the remainder of the lease terms are as follows (in thousands):


Years Ending December 31,	As of September 30, 2021
2021 (1)	$	97
2022	715
2023	736
2024	759
2025	781
All remaining years	467
Total future minimum rental payments	$	3,555
Less amount of lease payments representing interest	614
Total present value of lease payments	$	2,941

As of December 31, 2020, operating lease payments over the remainder of the lease terms were as follows (in thousands):


Years Ending December 31,	As of December 31, 2020

2021	$	260
2022	715
2023	736
2024	759
2025	781
Thereafter	467
Total future minimum rental payments	$	3,718
Less amount of lease payments representing interest	792
Total present value of lease payments	$	2,926

Equity Transactions and Share-based Compensation (Tables)

9 Months Ended

Sep. 30, 2021

Share-based Payment Arrangement [Abstract]

Schedule of employee and non-employee share-based compensation expense recognized related to stock options, the ESPP and RSUs

Total share-based compensation expense recognized related to stock options, the ESPP and RSUs was as follows (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Research and development expense	$	1,853	$	625	$	4,995	$	2,090
General and administrative expense	1,578		657		4,132		1,910
Total share-based compensation expense	$	3,431	$	1,282	$	9,127	$	4,000

Oncoceutics Acquisition (Tables)

9 Months Ended

Sep. 30, 2021

Business Combination and Asset Acquisition [Abstract]

Asset acquisition

The following represents the consideration paid and purchase price allocation for the acquisition of Oncoceutics (in thousands, except for per share data):


Cash	$	23,836
One-year closing anniversary payment	14,000

Shares common stock issued as consideration	8,723,769
Stock price per share on effective date	4.98
Value of estimated common stock consideration	43,445
Total consideration	$	81,281

Net assets acquired	$	(1,310)
IPR&D assets expensed	82,591
Total purchase price allocated	$	81,281

Transaction costs expensed to IPR&D(1)	$	299
Total IPR&D expensed	$	82,890

The Business and Summary of Significant Accounting Policies - Narrative (Details)	9 Months Ended
	Sep. 30, 2021 USD ($) product segment
Accounting Policies [Abstract]
Number of product candidates \| product	2
Number of segments \| segment	1
Inventory, work in process	$ 1,600,000
Inventory, finished goods	$ 0

The Business and Summary of Significant Accounting Policies - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Fair Value, Separate Account Investment
Short-term investments, available-for-sale	$ 96,384	$ 31,973
Long-term investments	2,035	0
Fair value, measurements, recurring
Fair Value, Separate Account Investment
Cash equivalents	20,165	1,503
Short-term investments, available-for-sale	96,384	31,973
Long-term investments	2,035
Total assets	118,584	33,476
Fair value, measurements, recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Separate Account Investment
Cash equivalents	20,165	1,503
Short-term investments, available-for-sale	7,534	28,715
Long-term investments	2,035
Total assets	29,734	30,218
Fair value, measurements, recurring \| Significant Other Observable Inputs (Level 2)
Fair Value, Separate Account Investment
Cash equivalents	0	0
Short-term investments, available-for-sale	88,850	3,258
Long-term investments	0
Total assets	88,850	3,258
Fair value, measurements, recurring \| Significant Unobservable Inputs (Level 3)
Fair Value, Separate Account Investment
Cash equivalents	0	0
Short-term investments, available-for-sale	0	0
Long-term investments	0
Total assets	0	0
U.S. treasury securities \| Fair value, measurements, recurring
Fair Value, Separate Account Investment
Short-term investments, available-for-sale	7,534	28,715
Long-term investments	2,035
U.S. treasury securities \| Fair value, measurements, recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Separate Account Investment
Short-term investments, available-for-sale	7,534	28,715
Long-term investments	2,035
U.S. treasury securities \| Fair value, measurements, recurring \| Significant Other Observable Inputs (Level 2)
Fair Value, Separate Account Investment
Short-term investments, available-for-sale	0	0
Long-term investments	0
U.S. treasury securities \| Fair value, measurements, recurring \| Significant Unobservable Inputs (Level 3)
Fair Value, Separate Account Investment
Short-term investments, available-for-sale	0	0
Long-term investments	0
Commercial paper \| Fair value, measurements, recurring
Fair Value, Separate Account Investment
Short-term investments, available-for-sale	51,277
Commercial paper \| Fair value, measurements, recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Separate Account Investment
Short-term investments, available-for-sale	0
Commercial paper \| Fair value, measurements, recurring \| Significant Other Observable Inputs (Level 2)
Fair Value, Separate Account Investment
Short-term investments, available-for-sale	51,277
Commercial paper \| Fair value, measurements, recurring \| Significant Unobservable Inputs (Level 3)
Fair Value, Separate Account Investment
Short-term investments, available-for-sale	0
Corporate bonds \| Fair value, measurements, recurring
Fair Value, Separate Account Investment
Short-term investments, available-for-sale	37,573	3,258
Corporate bonds \| Fair value, measurements, recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Separate Account Investment
Short-term investments, available-for-sale	0	0
Corporate bonds \| Fair value, measurements, recurring \| Significant Other Observable Inputs (Level 2)
Fair Value, Separate Account Investment
Short-term investments, available-for-sale	37,573	3,258
Corporate bonds \| Fair value, measurements, recurring \| Significant Unobservable Inputs (Level 3)
Fair Value, Separate Account Investment
Short-term investments, available-for-sale	0	0
Money market funds \| Fair value, measurements, recurring
Fair Value, Separate Account Investment
Cash equivalents	20,165	1,503
Money market funds \| Fair value, measurements, recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Separate Account Investment
Cash equivalents	20,165	1,503
Money market funds \| Fair value, measurements, recurring \| Significant Other Observable Inputs (Level 2)
Fair Value, Separate Account Investment
Cash equivalents	0	0
Money market funds \| Fair value, measurements, recurring \| Significant Unobservable Inputs (Level 3)
Fair Value, Separate Account Investment
Cash equivalents	$ 0	$ 0

The Business and Summary of Significant Accounting Policies - Schedule of Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Accounting Policies [Abstract]
Accrued research and development expenses	$ 3,276	$ 1,375
Accrued compensation	4,502	4,473
Accrued legal expenses	213	651
Other accrued liabilities	2,507	751
Total accrued liabilities	$ 10,498	$ 7,250

The Business and Summary of Significant Accounting Policies - Revenue Recognition (Details)	1 Months Ended		3 Months Ended		9 Months Ended		127 Months Ended
	Oct. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2021 USD ($) grant	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) grant	Sep. 30, 2020 USD ($)	Sep. 01, 2021 USD ($) segment contract
Collaborative Arrangement and Arrangement Other than Collaborative
Total revenues			$ 107,000	$ 1,609,000	$ 1,933,000	$ 4,252,000
SymBio Pharmaceuticals
Collaborative Arrangement and Arrangement Other than Collaborative
Total revenues	$ 5,000,000
Grant \| Oncoceutics, Inc.
Collaborative Arrangement and Arrangement Other than Collaborative
Total revenues			18,000		400,000
Deferred revenue			200,000		200,000
BARDA
Collaborative Arrangement and Arrangement Other than Collaborative
Total revenues			$ 100,000	$ 1,600,000	$ 1,600,000	$ 4,200,000
Total number of base segments \| segment							1
Total number of option segments \| segment							4
Total number of separate contracts \| contract							5
BARDA \| Expense reimbursement
Collaborative Arrangement and Arrangement Other than Collaborative
Total revenues							$ 72,500,000
BARDA \| Fees
Collaborative Arrangement and Arrangement Other than Collaborative
Total revenues							$ 4,600,000
Federal Goverment \| Oncoceutics, Inc.
Collaborative Arrangement and Arrangement Other than Collaborative
Number of grants \| grant			2		2
Private Foundations \| Oncoceutics, Inc.
Collaborative Arrangement and Arrangement Other than Collaborative
Number of grants \| grant			2		2
SymBio Pharmaceuticals
Collaborative Arrangement and Arrangement Other than Collaborative
Total revenues		$ 5,000,000
Payment to be received upon achievement of milestones		$ 180,000,000
License agreement cost	$ 5,000,000

Investments - Summary of Available-for-Sale securities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Schedule of Investments
Amortized Cost	$ 98,419	$ 31,973
Gross Unrealized Gains	10	3
Gross Unrealized Losses	(10)	(3)
Estimated Fair Value	98,419	31,973
Corporate bonds
Schedule of Investments
Amortized Cost	37,579	3,256
Gross Unrealized Gains	1	2
Gross Unrealized Losses	(7)	0
Estimated Fair Value	37,573	3,258
U.S. treasury securities
Schedule of Investments
Amortized Cost	9,568	28,717
Gross Unrealized Gains	2	1
Gross Unrealized Losses	(1)	(3)
Estimated Fair Value	9,569	$ 28,715
Commercial paper
Schedule of Investments
Amortized Cost	51,272
Gross Unrealized Gains	7
Gross Unrealized Losses	(2)
Estimated Fair Value	$ 51,277

Investments - Summary of Investments with Unrealized Losses, Aggregated by Investment Type and the Length of Time (Details) $ in Thousands	Sep. 30, 2021 USD ($) security	Dec. 31, 2020 USD ($) security
Debt Securities, Available-for-sale
Fair value, less than 12 months	$ 45,079	$ 16,598
Unrealized loss, less than 12 months	(10)	(3)
Fair value, greater than 12 months	0	0
Unrealized loss, greater than 12 months	0	0
Fair value, total	45,079	16,598
Unrealized loss, total	$ (10)	$ (3)
Number of securities with unrealized losses, less than 12 months \| security	16	6
Number of securities with unrealized losses, greater than 12 months \| security	0	0
Number of securities with unrealized losses, total \| security	16	6
Corporate bonds
Debt Securities, Available-for-sale
Fair value, less than 12 months	$ 27,554
Unrealized loss, less than 12 months	(7)
Fair value, greater than 12 months	0
Unrealized loss, greater than 12 months	0
Fair value, total	27,554
Unrealized loss, total	(7)
Commercial paper
Debt Securities, Available-for-sale
Fair value, less than 12 months	10,491
Unrealized loss, less than 12 months	(2)
Fair value, greater than 12 months	0
Unrealized loss, greater than 12 months	0
Fair value, total	10,491
Unrealized loss, total	(2)
U.S. treasury securities
Debt Securities, Available-for-sale
Fair value, less than 12 months	7,034	$ 16,598
Unrealized loss, less than 12 months	(1)	(3)
Fair value, greater than 12 months	0	0
Unrealized loss, greater than 12 months	0	0
Fair value, total	7,034	16,598
Unrealized loss, total	$ (1)	$ (3)

Investments - Schedule of Investment Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value
Maturing in one year or less	$ 96,384
Maturing after one year through two years	2,035
Total debt investments	$ 98,419	$ 31,973

Commitments and Contingencies - Narrative (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($) ft²	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) ft²	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Weighted average remaining lease term	4 years 10 months 2 days		4 years 10 months 2 days
Rent expense under non-cancelable operating leases	$ 200	$ 200	$ 500	$ 600
Weighted average discount rate	7.89%		7.89%
Lease payments	$ 122	181	$ 292	538
Area of sublease space (in sq ft) \| ft²	3,537		3,537
Sublease income	$ 0	$ 18	$ 12	$ 53
BARDA \| Refundable Agreements
Disaggregation of Revenue
Provision for refundable amounts	$ 52		$ 52		$ 38

Commitments and Contingencies - Operating Lease Right-of-Use Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Assets
Operating lease right-of-use assets	$ 2,509	$ 2,825
Liabilities
Operating lease short-term liabilities (recorded within Accrued liabilities)	416
Operating lease long-term liabilities (recorded within Lease-related obligations)	2,525	2,814
Total present value of lease payments	$ 2,941	$ 2,926
Operating lease, liability, current, statement of financial position [extensible list]	us-gaap:AccruedLiabilitiesCurrent	us-gaap:AccruedLiabilitiesCurrent

Commitments and Contingencies - Maturity Analysis of Operating Lease Liabilities (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Lessee, Operating Lease, Liability, Payment, Due
Remainder of fiscal year	$ 97
Year one	715	$ 260
Year two	736	715
Year three	759	736
Year four	781	759
Year five		781
Thereafter		467
All remaining years	467
Total future minimum rental payments	3,555	3,718
Less amount of lease payments representing interest	614	792
Total present value of lease payments	$ 2,941	$ 2,926
Lease extension term	65 months
Rent abatement term	5 months

Equity Transactions and Share-based Compensation - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended		9 Months Ended
	Jan. 20, 2021	Jan. 01, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award
Common stock, par value (in dollars per share)	$ 0.001		$ 0.001		$ 0.001		$ 0.001
Shares issued for restricted stock units (in shares)			241,000	277,000	410,000	440,000
Public Stock Offering
Share-based Compensation Arrangement by Share-based Payment Award
Number of shares sold (in shares)	11,765,000
Price of shares sold (in dollars per share)	$ 8.50
Proceeds from shares sold	$ 107.8
Underwriter's Option
Share-based Compensation Arrangement by Share-based Payment Award
Number of shares sold (in shares)	1,764,750
Price of shares sold (in dollars per share)	$ 7.99
Purchase option term	30 days
The 2013 Plan
Share-based Compensation Arrangement by Share-based Payment Award
Evergreen option provision, equity increase					4.00%
Additional shares authorized (in shares)		2,500,000
Number of shares reserved for future issuance (in shares)			2,200,000		2,200,000
Shares issued pursuant to the exercise of stock options (in shares)			75,000	21,000	826,000	263,000
The 2013 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award
Evergreen option provision, equity increase					1.00%
Additional shares authorized (in shares)		422,535
Number of shares reserved for future issuance (in shares)			2,300,000		2,300,000
Number of shares authorized to be granted (in shares)			3,900,000		3,900,000
Number of shares reserved for issuance, annual increase (in shares)					422,535
Participation term					24 months
Percentage of pay that employee can contribute, maximum			15.00%		15.00%
Discounted purchase price from market price, offering date					15.00%
Discounted purchase price from market price, purchase date					15.00%
Purchase interval					6 months
Shares issued pursuant to employee stock purchase plan (in shares)			283,000	160,000	543,000	337,000

Equity Transactions and Share-based Compensation - Schedule of Share-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Payment Arrangement, Expensed and Capitalized, Amount
Total share-based compensation expense	$ 3,431	$ 1,282	$ 9,127	$ 4,000
Research and development expense
Share-based Payment Arrangement, Expensed and Capitalized, Amount
Total share-based compensation expense	1,853	625	4,995	2,090
General and administrative expense
Share-based Payment Arrangement, Expensed and Capitalized, Amount
Total share-based compensation expense	$ 1,578	$ 657	$ 4,132	$ 1,910

Income Taxes (Details) - USD ($)	9 Months Ended	12 Months Ended
Income Taxes (Details) - USD ($)	Sep. 30, 2021	Dec. 31, 2021
Income Tax Contingency
Federal or state income taxes	$ 0
Unrecognized tax benefits	$ 0
Scenario, Forecast
Income Tax Contingency
Estimated annual effective tax rate		0.00%

- Definition

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

+ References + Details

Significant Agreements (Details)	1 Months Ended				3 Months Ended		9 Months Ended		127 Months Ended
Significant Agreements (Details)	Dec. 31, 2020 USD ($)	Oct. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Feb. 28, 2011 extension	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 01, 2021 USD ($)	Dec. 31, 2019 USD ($)	Jul. 26, 2019 USD ($)
Long-term Purchase Commitment
Total revenues					$ 107,000	$ 1,609,000	$ 1,933,000	$ 4,252,000
SymBio Pharmaceuticals
Long-term Purchase Commitment
Total revenues		$ 5,000,000
BARDA
Long-term Purchase Commitment
Number of extension periods \| extension				4
Total revenues					$ 100,000	$ 1,600,000	$ 1,600,000	$ 4,200,000
BARDA \| Expense reimbursement
Long-term Purchase Commitment
Total revenues									$ 72,500,000
BARDA \| Fees
Long-term Purchase Commitment
Total revenues									$ 4,600,000
Cantex Pharmaceuticals Inc.
Long-term Purchase Commitment
Payments to be made for regulatory milestones (up to)											$ 202,500,000
Payments to be made upon achievement of specified net sales levels (up to)											$ 385,000,000
Royalty percentage to be paid (at least)											10.00%
SymBio Pharmaceuticals
Long-term Purchase Commitment
Total revenues			$ 5,000,000
Termination notice period			90 days
Payment to be received upon achievement of milestones			$ 180,000,000
Ohara Pharmaceutical Co., Ltd.
Long-term Purchase Commitment
License agreement, nonrefundable regulatory milestone payment to be received										$ 2,500,000
CR Sanjui \| Oncoceutics, Inc.
Long-term Purchase Commitment
Total revenues	$ 5,000,000

Oncoceutics Acquisition - Narrative (Details) - Oncoceutics, Inc. - USD ($) $ in Thousands	Jan. 07, 2021	Sep. 30, 2021
Asset Acquisition
Cash payment for acquisition	$ 25,000
Number of shares issued for acquisition	8,723,769
Debt issued for acquisition	$ 14,000
Contingent consideration for acquisition	$ 360,000
Liability for closing payment adjustments		$ 200
Accounts and notes receivable net		$ 600

Oncoceutics Acquisition - Consideration Paid and Purchase Price Allocation (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended			9 Months Ended
	Jan. 07, 2021	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Asset Acquisition
IPR&D assets expensed		$ 0		$ 0	$ 82,890	$ 0
Oncoceutics, Inc.
Asset Acquisition
Cash	$ 23,836
One-year closing anniversary payment	$ 14,000
Shares common stock issued as consideration (in shares)	8,723,769
Stock price per share on effective date (in USD per share)	$ 4.98
Value of estimated common stock consideration	$ 43,445
Total consideration	81,281
Net assets acquired	(1,310)
IPR&D assets expensed	82,591
Total purchase price allocated	81,281
Transaction costs expensed to IPR&D	299
Transaction costs expensed to IPR&D	$ 82,890
Transaction expenses			$ 600

Subsequent Events (Details) $ in Thousands	3 Months Ended
Subsequent Events (Details) $ in Thousands	Dec. 31, 2021 USD ($)
Subsequent Event \| Scenario, Forecast
Subsequent Event
Milestone payments for ORR	$ 20,000