Moderna (MRNA) 10-K 26 Feb 21 2020 FY Annual report Financial data

Cover

Cover - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Feb. 16, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	001-38753
Entity Registrant Name	Moderna, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	81-3467528
Entity Address, Address Line One	200 Technology Square
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02139
City Area Code	617
Local Phone Number	714-6500
Title of 12(b) Security	Common stock, par value $0.0001 per share
Trading Symbol	MRNA
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 25,250
Entity Common Stock, Shares Outstanding		399,769,582
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Portions of the registrant’s Definitive Proxy Statement relating to its 2021 Annual Meeting of Stockholders to be filed hereafter are incorporated by reference into Part III of this Annual Report on Form 10-K where indicated.
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Central Index Key	0001682852
Current Fiscal Year End Date	--12-31
ICFR Auditor Attestation Flag	true

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 2,623,850,000	$ 235,876,000
Investments	1,983,758,000	867,124,000
Accounts receivable	1,390,560,000	5,369,000
Inventory	46,527,000	0
Prepaid expenses and other current assets	252,152,000	19,403,000
Restricted cash	1,032,000	1,032,000
Total current assets	6,297,879,000	1,128,804,000
Investments, non-current	638,848,000	159,987,000
Property and equipment, net	296,889,000	201,495,000
Right-of-use assets, operating leases	90,201,000	86,414,000
Restricted cash, non-current	11,053,000	10,791,000
Other non-current assets	1,880,000	1,931,000
Total assets	7,336,750,000	1,589,422,000
Current liabilities:
Accounts payable	18,359,000	7,090,000
Accrued liabilities	469,591,000	67,652,000
Deferred revenue	3,867,193,000	63,310,000
Other current liabilities	33,665,000	5,063,000
Total current liabilities	4,388,808,000	143,115,000
Contract with Customer, Liability, Noncurrent	177,419,000	138,995,000
Operating lease liabilities, non-current	97,421,000	93,675,000
Financing lease liabilities, non-current	109,874,000	38,689,000
Other non-current liabilities	1,853,000	138,000
Total liabilities	4,775,375,000	414,612,000
Commitments and contingencies (Note 12)
Stockholders’ equity:
Preferred stock, $0.0001 par value; 162,000,000 shares authorized at December 31, 2020 and 2019; 0 shares issued or outstanding at December 31, 2020 and 2019	0	0
Common stock, par value $0.0001; 1,600,000,000 shares authorized as of December 31, 2020 and 2019; 398,787,678 and 336,536,985 shares issued and outstanding as of December 31, 2020 and 2019, respectively	40,000	34,000
Additional paid-in capital	4,801,849,000	2,669,426,000
Accumulated other comprehensive gain	3,004,000	1,804,000
Accumulated deficit	(2,243,518,000)	(1,496,454,000)
Total stockholders’ equity	2,561,375,000	1,174,810,000
Total liabilities and stockholders’ equity	$ 7,336,750,000	$ 1,589,422,000

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Preferred stock, par value (usd per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	162,000,000	162,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (usd per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	1,600,000,000	1,600,000,000
Common stock, shares issued (in shares)	398,787,678	336,536,985
Common stock, shares outstanding (in shares)	398,787,678	336,536,985

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue:
Revenues	$ 803,395	$ 60,209	$ 135,068
Operating expenses:
Cost of sales	7,933	0	0
Research and development	1,370,339	496,309	454,082
Selling, general and administrative	188,267	109,620	94,252
Total operating expenses	1,566,539	605,929	548,334
Loss from operations	(763,144)	(545,720)	(413,266)
Interest income	24,715	38,530	27,023
Other (expense) income, net	(6,084)	(7,526)	1,835
Loss before provision for (benefit from) income taxes	(744,513)	(514,716)	(384,408)
Provision for (benefit from) income taxes	2,551	(695)	326
Net loss	(747,064)	(514,021)	(384,734)
Reconciliation of net loss to net loss attributable to common stockholders:
Premium paid on repurchase of preferred stock	0	0	(4,127)
Cumulative preferred stock dividends	0	0	(12,996)
Net loss attributable to common stockholders	$ (747,064)	$ (514,021)	$ (401,857)
Net loss per share attributable to common stockholders, basic and diluted (usd per share)	$ (1.96)	$ (1.55)	$ (4.95)
Weighted average common shares used in net loss per share attributable to common stockholders, basic and diluted (in shares)	381,333,059	330,802,136	81,114,183
Grant revenue
Revenue:
Revenues	$ 528,905	$ 12,173	$ 12,556
Product sales
Revenue:
Revenues	199,872	0	0
Collaboration revenue
Revenue:
Revenues	$ 74,618	$ 48,036	$ 122,512

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net loss	$ (747,064)	$ (514,021)	$ (384,734)
Other comprehensive income (loss):
Unrealized gain (loss) on available-for-sale debt securities, net of tax of $0, $1,148 and $0, for the years ended December 31, 2020, 2019 and 2018, respectively	2,501	3,447	(132)
Less: amounts recognized for net realized gain included in net loss	(1,301)	(323)	(31)
Total other comprehensive income (loss)	1,200	3,124	(163)
Comprehensive loss	$ (745,864)	$ (510,897)	$ (384,897)

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Unrealized gain (loss) on available-for-sale debt securities, tax	$ 0	$ 1,148	$ 0

CONSOLIDATED STATEMENTS OF REDE

CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Series G Redeemable Convertible Preferred Stock	Series D Redeemable Convertible Preferred Stock	Series E Redeemable Convertible Preferred Stock	Redeemable Convertible Preferred Stock	Redeemable Convertible Preferred StockSeries G Redeemable Convertible Preferred Stock	Redeemable Convertible Preferred StockSeries H Redeemable Convertible Preferred Stock	Redeemable Convertible Preferred StockSeries D Redeemable Convertible Preferred Stock	Redeemable Convertible Preferred StockSeries E Redeemable Convertible Preferred Stock	Common Stock	Additional Paid-In Capital	Additional Paid-In CapitalSeries G Redeemable Convertible Preferred Stock	Additional Paid-In CapitalSeries D Redeemable Convertible Preferred Stock	Additional Paid-In CapitalSeries E Redeemable Convertible Preferred Stock	Accumulated Other Comprehensive Gain (Loss)	Accumulated Deficit	Accumulated DeficitCumulative Effect, Period of Adoption, Adjustment
Balance at beginning of period (in shares) at Dec. 31, 2017						448,686,791
Balance at beginning of period at Dec. 31, 2017						$ 1,176,661
Increase (Decrease) in Temporary Equity [Roll Forward]
Issuance of redeemable convertible preferred stock, net of issuance costs (in shares)							55,666,004	5,000,000
Issuance of redeemable convertible preferred stock, net of issuance costs			$ 51				$ 549,413	$ 111,546					$ 51
Repurchase of redeemable convertible preferred stock (in shares)									(269,180)	(544,100)
Repurchase of redeemable convertible preferred stock				$ (2,009)	$ (2,118)				$ (704)	$ (3,355)				$ (2,009)	$ (2,118)
Conversion of redeemable convertible preferred stock into common stock (in shares)						(508,539,515)					(236,012,913)
Conversion of redeemable convertible preferred stock into common stock	$ 1,833,561					$ (1,833,561)					$ 24	$ 1,833,537
Balance at end of period (in shares) at Dec. 31, 2018						0
Balance at end of period at Dec. 31, 2018						$ 0
Balance at beginning of period (in shares) at Dec. 31, 2017											65,206,999
Balance at beginning of period at Dec. 31, 2017	(551,365)										$ 6	71,679				$ (1,157)	$ (621,893)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Vesting of restricted common stock (in shares)											856,135
Exercise of options to purchase common stock (in shares)											446,864
Exercise of options to purchase common stock	1,427											1,427
Conversion of redeemable convertible preferred stock into common stock (in shares)						508,539,515					236,012,913
Conversion of redeemable convertible preferred stock into common stock	1,833,561					$ (1,833,561)					$ 24	1,833,537
Proceeds of initial public offering, net of issuance costs (in shares)											26,275,993
Proceeds of initial public offering, net of issuance costs	563,026										$ 3	563,023
Stock-based compensation	72,565											72,565
Other comprehensive income, net of tax	(163)															(163)
Net loss	(384,734)																(384,734)
Balance at end of period (in shares) at Dec. 31, 2018											328,798,904
Balance at end of period at Dec. 31, 2018	$ 1,530,241										$ 33	2,538,155				(1,320)	(1,006,627)
Balance at end of period (Accounting Standards Update 2014-09) at Dec. 31, 2018		$ 27,984																$ 27,984
Balance at end of period (Accounting Standards Update 2016-02) at Dec. 31, 2018		$ (3,790)																$ (3,790)
Balance at end of period (in shares) at Dec. 31, 2019	0					0
Balance at end of period at Dec. 31, 2019						$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Vesting of restricted common stock (in shares)											621,432
Exercise of options to purchase common stock (in shares)											6,945,306
Exercise of options to purchase common stock	$ 47,259										$ 1	47,258
Purchase of common stock under employee stock purchase plan (in shares)											171,343
Purchase of common stock under employee stock purchase plan	2,891											2,891
Stock-based compensation	81,122											81,122
Other comprehensive income, net of tax	3,124															3,124
Net loss	(514,021)																(514,021)
Balance at end of period (in shares) at Dec. 31, 2019											336,536,985
Balance at end of period at Dec. 31, 2019	$ 1,174,810										$ 34	2,669,426				1,804	(1,496,454)
Balance at end of period (in shares) at Dec. 31, 2020	0					0
Balance at end of period at Dec. 31, 2020						$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Vesting of restricted common stock (in shares)											247,349
Exercise of options to purchase common stock (in shares)	13,888,434										13,888,434
Exercise of options to purchase common stock	$ 179,643										$ 1	179,642
Purchase of common stock under employee stock purchase plan (in shares)											251,752
Purchase of common stock under employee stock purchase plan	7,040											7,040
Proceeds of initial public offering, net of issuance costs (in shares)											47,863,158
Proceeds of initial public offering, net of issuance costs	1,852,725										$ 5	1,852,720
Stock-based compensation	93,021											93,021
Other comprehensive income, net of tax	1,200															1,200
Net loss	(747,064)																(747,064)
Balance at end of period (in shares) at Dec. 31, 2020											398,787,678
Balance at end of period at Dec. 31, 2020	$ 2,561,375										$ 40	$ 4,801,849				$ 3,004	$ (2,243,518)

CONSOLIDATED STATEMENTS OF RE_2

CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS’ EQUITY (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Issuance costs	$ 41,322
Series G Redeemable Convertible Preferred Stock
Issuance costs	10,517
Series H Redeemable Convertible Preferred Stock
Issuance costs	$ 474

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating activities
Net loss	$ (747,064)	$ (514,021)	$ (384,734)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	93,021	81,122	72,565
Depreciation and amortization	31,251	31,021	24,862
Leased assets expensed	62,286	0	0
Amortization/accretion of investments	10,185	(3,742)	(1,866)
Loss on disposal of property and equipment	238	316	891
Changes in assets and liabilities:
Accounts receivable	(1,385,191)	7,216	832
Inventory	(46,527)	0	0
Prepaid expenses and other assets	(241,041)	9,751	(5,289)
Right-of-use assets, operating leases	(10,542)	(5,664)	0
Accounts payable	11,875	(23,964)	15,017
Accrued liabilities	388,392	(3,362)	8,787
Deferred revenue	3,842,307	(44,119)	(65,260)
Deferred lease obligation	0	0	2,420
Operating lease liabilities	11,792	12,647	0
Other liabilities	5,989	(6,169)	910
Net cash provided by (used in) operating activities	2,026,971	(458,968)	(330,865)
Investing activities
Purchases of marketable securities	(2,956,295)	(1,145,226)	(1,227,709)
Proceeds from maturities of marketable securities	1,137,129	993,181	783,373
Proceeds from sales of marketable securities	214,686	168,654	177,008
Purchases of property and equipment	(67,448)	(31,554)	(105,766)
Net cash used in investing activities	(1,671,928)	(14,945)	(373,094)
Financing activities
Proceeds from issuance of redeemable convertible preferred stock, net of issuance costs	0	0	661,111
Proceeds from offerings of common stock, net of issuance costs	1,852,725	0	563,026
Repurchases of redeemable convertible preferred stock	0	0	(8,182)
Proceeds from issuance of common stock under equity plans	179,643	47,259	1,427
Proceeds from purchase of common stock under employee stock purchase plan	7,040	2,891	0
Charges to financing lease liabilities	(6,215)	971	0
Reimbursement of assets under financing lease obligation	0	0	11,635
Payments on financing lease obligation	0	0	(2,175)
Net cash provided by financing activities	2,033,193	51,121	1,226,842
Net increase (decrease) in cash, cash equivalents and restricted cash	2,388,236	(422,792)	522,883
Cash, cash equivalents and restricted cash, beginning of year	247,699	670,491	147,608
Cash, cash equivalents and restricted cash, end of year	2,635,935	247,699	670,491
Supplemental cash flow information
Cash paid for income taxes	572	416	294
Cash paid for interest	8,528	5,585	2,998
Non-cash investing and financing activities
Issuance costs included in accounts payable and accrued liabilities	0	0	2,638
Purchases of property and equipment included in accounts payable and accrued liabilities	17,617	4,676	12,892
Leasehold improvements included in prepaid and other current assets	0	0	10,089
Lease financing obligation	$ 0	$ 0	$ 10,089

Organization and Description of

Organization and Description of Business	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	Organization and Description of Business Moderna, Inc. (collectively, with its consolidated subsidiaries, any of Moderna, we, us, or the Company) was incorporated in Delaware on July 22, 2016. We are the successor in interest to Moderna LLC, a limited liability company formed under the laws of the State of Delaware in 2013. Our principal executive office is located at 200 Technology Square, Cambridge, MA. We are a biotechnology company creating a new generation of transformative medicines based on messenger RNA (mRNA), to improve the lives of patients. mRNA medicines are designed to direct the body’s cells to produce intracellular, membrane, or secreted proteins that have a therapeutic or preventive benefit with the potential to address a broad spectrum of diseases. Our platform builds on continuous advances in basic and applied mRNA science, delivery technology, and manufacturing, providing us the capability to pursue in parallel a robust pipeline of new development candidates. We are developing vaccines and therapeutics for infectious diseases, immuno-oncology, rare diseases, autoimmune and cardiovascular diseases, independently and with our strategic collaborators. In December 2020, we received an Emergency Use Authorization (EUA) from the U.S. Food and Drug Administration (FDA) and an Interim Order from Health Canada authorizing the Moderna COVID-19 vaccine (also referred to as mRNA-1273) in the U.S. and Canada. Since inception, we have incurred significant net losses, which were $747.1 million, $514.0 million, and $384.7 million for the years ended December 31, 2020, 2019 and 2018, respectively. On February 14, 2020 and May 21, 2020, we sold 30,263,158 and 17,600,000 shares of common stock at a price of $19.00 and $76.00 per share through public equity offerings, with aggregate net proceeds from the offering of $549.5 million and $1.30 billion, respectively, net of underwriting discounts, commissions and offering expenses. As of December 31, 2020, we had an accumulated deficit of $2.24 billion. As of December 31, 2020, we had 21 mRNA development programs in our portfolio with 13 having entered the clinic. We expect to continue to incur significant expenses for the foreseeable future. If we seek to obtain regulatory approval for any of our investigational medicines, we expect to incur significant commercialization expenses. In addition, we anticipate that our expenses will increase significantly in connection with our development and commercializing our mRNA-1273 vaccine and ongoing activities to support our platform research, drug discovery and clinical development, including development of any new generations of vaccines against variants of SARS-CoV-2, infrastructure and Research Engine and Early Development Engine (which includes our Moderna Technology Center), digital infrastructure, creation of a portfolio of intellectual property, and administrative support. We may finance our future cash needs that exceed our operating costs through a combination of public or private equity offerings, structured financings and debt financings, government funding arrangements, strategic alliances and marketing, manufacturing, distribution and licensing arrangements. We may be unable to raise additional funds or enter into such other agreements on favorable terms, or at all. We believe that our cash, cash equivalents, and investments as of December 31, 2020 will be sufficient to enable us to fund our projected operations through at least the next 12 months from the issuance of our financial statements. We are subject to numerous risks and uncertainties associated with pharmaceutical development and commercialization, and we are unable to predict the timing or amount of expenses or when or if we will be able to achieve or maintain profitability. If we fail to become profitable or are unable to sustain profitability on a continuing basis, then we may be unable to continue our operations at planned levels and be forced to reduce our operations.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation and Principles of Consolidation Our consolidated financial statements are prepared in accordance with U.S. generally accepted accounting principles (GAAP). Any reference in these notes to applicable guidance is meant to refer to the authoritative accounting principles generally accepted in the United States as found in the Accounting Standard Codification (ASC) and Accounting Standards Updates (ASU) of the Financial Accounting Standards Board (FASB). The consolidated financial statements include the Company and its subsidiaries. All intercompany transactions and balances have been eliminated in consolidation. Use of Estimates We have made estimates and judgments affecting the amounts reported in our consolidated financial statements and the accompanying notes. On an ongoing basis, we evaluate our estimates, including critical accounting policies or estimates related to revenue recognition, research and development expenses, income tax provisions, stock-based compensation, leases, derivative financial instruments, inventory, and useful lives of long-lived assets. We base our estimates on historical experience and various relevant assumptions that we believe 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. The actual results that we experience may differ materially from our estimates. Significant estimates relied upon in preparing these financial statements include, among others, those related to fair value of equity awards, revenue recognition, research and development expenses, leases, fair value of financial instruments, useful lives of property and equipment, income taxes, and our valuation allowance on our deferred tax assets. Segment Information We have determined that our chief executive officer is the chief operating decision maker (CODM). The CODM reviews financial information presented on a consolidated basis. Resource allocation decisions are made by the CODM based on consolidated results. There are no segment managers who are held accountable by the CODM for operations, operating results, and planning for levels or components below the consolidated unit level. As such, we have concluded that we operate as one segment. Revenue Recognition On January 1, 2019, we adopted ASC 606 (Revenue from Contracts with Customers ) using the modified retrospective transition method applied to those contracts which were not completed as of January 1, 2019. We recognized the cumulative effect of the adoption as an adjustment to the opening balance of accumulated deficit in the current period consolidated balance sheet. Results for reporting periods beginning after January 1, 2019 are presented under ASC 606, while prior period amounts have not been adjusted and continue to be reported in accordance with our historic accounting (ASC 605). ASC 606 applies to all contracts with customers, except for contracts that are within the scope of other standards, such as leases, insurance, collaboration arrangements and financial instruments. To determine the appropriate amount of revenue to be recognized for arrangements that we determine are within the scope of ASC 606, we perform the following five steps (the five-step model): (i) identify the contract(s) with our customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when or as each performance obligation is satisfied. Our revenue is primarily generated through grants from government-sponsored and private organizations, product sales and collaboration arrangements. Grant Revenue We have contracts with Biomedical Advanced Research and Development Authority (BARDA), a division of the Office of the Assistant Secretary for Preparedness and Response (ASPR) within the U.S. Department of Health and Human Services (HHS); the U.S. government’s Defense Advanced Research Projects Agency (DARPA); the Bill & Melinda Gates Foundation (Gates Foundation) and other government-sponsored and private organizations for research and development related activities that provide for payments for reimbursed costs, which may include overhead and general and administrative costs as well as a related profit margin. We recognize revenue from these contracts as we perform services under these arrangements when the funding is committed. Associated expenses are recognized when incurred as research and development expense. Revenues and related expenses are presented gross in the consolidated statements of operations as we have determined we are the primary obligor under the arrangements relative to the research and development services we perform as lead technical expert. Collaboration Revenue We account for a contract with a customer that is within the scope of ASC 606 using the five-step model. We account for a contract with a customer that is within the scope of ASC 606 when all of the following criteria are met: (i) the arrangement has been approved by the parties and the parties are committed to perform their respective obligations; (ii) each party’s rights regarding the goods and/or services to be transferred can be identified; (iii) the payment terms for the goods and/or services to be transferred can be identified; (iv) the arrangement has commercial substance; and (v) collection of substantially all of the consideration to which we will be entitled in exchange for the goods and/or services that will be transferred to the customer is probable. We also determine the term of the contract based on the period in which we and our customer have present and enforceable rights and obligations for purposes of identifying the performance obligations and determining the transaction price. We evaluate contracts that contain multiple promises to determine which promises are distinct. Promises are considered to be distinct and therefore, accounted for as separate performance obligations, provided that: (i) the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer and (ii) the promise to transfer the good or service to the customer is separately identifiable from other promises in the contract. Individual goods or services (or bundles of goods and/or services) that meet both criteria for being distinct are accounted for as separate performance obligations. Promises that are not distinct at contract inception are combined and accounted for as a single performance obligation. Options to acquire additional goods and/or services are evaluated to determine if such option provides a material right to the customer that it would not have received without entering into the contract. If so, the option is accounted for as a separate performance obligation. If not, the option is considered a marketing offer which would be accounted for as a separate contract upon the customer’s election. The transaction price is generally comprised of an upfront payment due at contract inception and variable consideration in the form of payments for our services and materials and milestone payments due upon the achievement of specified events. Other payments the Company could be entitled to include tiered royalties earned when customers recognize net sales of licensed products. We measure the transaction price based on the amount of consideration to which we expect to be entitled in exchange for transferring the promised goods and/or services to the customer. We utilize either the expected value method or the most likely amount method to estimate the amount of variable consideration, depending on which method is expected to better predict the amount of consideration to which we will be entitled. Amounts of variable consideration are included in the transaction price to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. With respect to arrangements that include payments for a development or regulatory milestone payment, we evaluate whether the associated event is considered probable of achievement and estimate the amount to be included in the transaction price using the most likely amount method. Milestone payments that are not within our control or the licensee, such as those dependent upon receipt of regulatory approval, are not considered to be probable of achievement until the triggering event occurs. At the end of each reporting period, we re-evaluate the probability of achievement of each milestone and any related constraint, and if necessary, adjust our estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenue and net loss in the period of adjustment. For arrangements that include sales-based royalties, including milestone payments based upon the achievement of a certain level of product sales, wherein the license is deemed to be the sole or predominant item to which the payments relate, we recognize revenue upon the later of: (i) when the related sales occur or (ii) when the performance obligation to which some or all of the payment has been allocated has been satisfied (or partially satisfied). Consideration that would be received for optional goods and/or services is excluded from the transaction price at contract inception. We generally allocate the transaction price to each performance obligation based on a relative standalone selling price basis. We develop assumptions that require judgment to determine the standalone selling price for each performance obligation in consideration of applicable market conditions and relevant entity-specific factors, including factors that were contemplated in negotiating the agreement with the customer and estimated research and development costs. However, in certain instances, we allocate variable consideration entirely to one or more performance obligation if the terms of the variable consideration relate to the satisfaction of the respective performance obligation and the amount allocated is consistent with the amount we would expect to receive for the satisfaction of the respective performance obligation. We recognize revenue based on the amount of the transaction price that is allocated to each respective performance obligation when or as the performance obligation is satisfied by transferring a promised good or service to the customer. For performance obligations that are satisfied at a point in time, we recognize revenue when control of the goods and/or services is transferred to the customer. For performance obligations that are satisfied over time, we recognize revenue by measuring the progress toward complete satisfaction of the performance obligation using a single method of measuring progress which depicts the performance in transferring control of the associated goods and/or services to the customer. We generally use input methods to measure the progress toward the complete satisfaction of performance obligations satisfied over time. With respect to arrangements containing a license to our intellectual property that is determined to be distinct from the other performance obligations identified in the arrangement, we recognize revenue from amounts allocated to the license when the license is transferred to the licensee and the licensee is able to use and benefit from the license. For licenses that are bundled with other promises, we utilize judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. Significant management judgment is required in determining the level of effort required under an arrangement and the period over which we are expected to complete our performance obligations under an arrangement. We evaluate the measure of progress each reporting period and, if necessary, adjust the measure of performance and related revenue recognition. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenue and net loss in the period of adjustment. Product Sales Product sales are associated with our COVID-19 vaccine supply agreements with the U.S. Government and international government agencies. These agreements generally do not provide provisions for various forms of variable consideration, such as discounts, rebates or returns. We recognize revenue from product sales, using the five-step model under ASC 606, based on the fixed price per dose according to the contracts when control of the product transfers to the customer and customer acceptance has occurred, unless such acceptance provisions are deemed perfunctory. Cash and Cash Equivalents We consider all highly liquid investments with an original maturity of 90 days or less from the date of purchase to be cash equivalents. Restricted Cash Restricted cash is composed of amounts held on deposit related to our lease arrangements. The funds are maintained in money market accounts and are recorded at fair value. We classify our restricted cash as either current or non-current based on the terms of the underlying lease arrangement. Cash, Cash Equivalents and Restricted Cash shown in the Consolidated Statements of Cash Flows The following table provides a reconciliation of cash, cash equivalents and restricted cash in the consolidated balance sheets that sum to the total of the same such amounts shown in the consolidated statements of cash flows (in thousands): December 31, 2020 2019 Cash and cash equivalents $ 2,623,850 $ 235,876 Restricted cash 1,032 1,032 Restricted cash, non-current 11,053 10,791 Total cash, cash equivalents and restricted cash shown in the consolidated $ 2,635,935 $ 247,699 Investments We invest our excess cash balances in marketable debt securities. We classify our investments in marketable debt securities as available-for-sale. We report available-for-sale investments at fair value at each balance sheet date, and include any unrealized holding gains and losses (the adjustment to fair value) in accumulated other comprehensive gain (loss), a component of stockholders’ equity. Realized gains and losses are determined using the specific-identification method, and are included in other (expense) income, net in our consolidated statements of operations. We classify our available-for-sale marketable securities as current or non-current based on each instrument’s underlying effective maturity date and for which we have the intent and ability to hold the investment for a period of greater than 12 months. Marketable securities with maturities of less than 12 months are classified as current and are included in investments in the consolidated balance sheets. Marketable securities with maturities greater than 12 months for which we have the intent and ability to hold the investment for greater than 12 months are classified as non-current and are included in investments, non-current in the consolidated balance sheets. We evaluate securities for impairment at the end of each reporting period. Impairment is evaluated considering numerous factors, and their relative significance varies depending on the situation. Factors considered include whether a decline in fair value below the amortized cost basis is due to credit-related factors or non-credit-related factors, the financial condition and near-term prospects of the issuer, and our intent and ability to hold the investment to allow for an anticipated recovery in fair value. A credit-related impairment is recognized as an allowance on the balance sheet with a corresponding adjustment to earnings. Any impairment that is not credit- related is recognized in other comprehensive (loss) income, net of applicable taxes. Accounts Receivable and Allowance for Doubtful Accounts We have accounts receivable amounts due from our product sales and related vaccine supply agreements and our grant agreements. We also have accounts receivable amounts due from strategic collaborators as a result of manufacturing and research and development services provided under collaboration arrangements, or milestones achieved, but not yet paid. Amounts payable to us are recorded as accounts receivable when our right to consideration is unconditional. To estimate the allowance for doubtful accounts, we make judgments about the creditworthiness of our customers based on ongoing credit evaluation and historical experience. There was no allowance for doubtful accounts at December 31, 2020, and 2019. There was no bad debt expense for the years ended December 31, 2020, 2019 or 2018. Concentrations of Credit Risk Financial instruments that subject us to significant concentrations of credit risk consist primarily of cash, cash equivalents, restricted cash, marketable securities, and accounts receivable. Our investment portfolio comprises money market funds, marketable debt securities, including U.S. Treasury securities, debt securities of U.S. government agencies and corporate entities and commercial paper. Our cash management and investment policy limits investment instruments to investment-grade securities with the objective to preserve capital and to maintain liquidity until the funds can be used in business operations. Bank accounts in the United States are insured by the Federal Deposit Insurance Corporation (FDIC) up to $250,000. Our primary operating accounts significantly exceed the FDIC limits. Significant Customers Our accounts receivable are generally unsecured and are from customers in different countries. We generated revenue from grants made by government-sponsored and private organizations, product sales to the U.S. Government and international government agencies, and to a lesser extent, strategic alliances in 2020. Historically, we generated revenue primarily from strategic alliances. A significant portion of our revenue to date has been generated from the following entities that accounted for more than 10% of total revenue and accounts receivable for the periods presented: Percentage of Revenue Years Ended December 31, Percentage of Accounts Receivable December 31, 2020 2019 2018 2020 2019 Merck * 61 % 49 % * 13 % BARDA 65 % 13 % * 22 % 54 % Vertex * 10 % * * 17 % AstraZeneca * * 34 % * * U.S. Government (excluding BARDA) 24 % * * * * European Commission * * * 28 % * United Kingdom Government * * * 11 % * South Korea Government * * * 24 % * ________ * - Represents an amount of less than 10% Derivative Instruments and Hedging Activities We record all derivatives on our consolidated balance sheets at fair value. The accounting for changes in the fair value of a derivative depends on whether the derivative has been designated and qualifies for hedge accounting. Hedge accounting generally provides for the matching of the timing of gain or loss recognition on the hedging instrument with the recognition of the changes in the fair value of the hedged asset or liability that are attributable to the hedged risk in a fair value hedge or the earnings effect of the hedged forecasted transactions in a cash flow hedge. We may enter into derivative contracts that are intended to economically hedge certain risk, even though hedge accounting does not apply or we elect not to apply hedge accounting. Foreign currency gains or losses associated with derivatives that are not designated as hedging instruments for accounting purposes are recorded within other (expense) income, net, in our consolidated statements of operations. Fair Value Measurements Fair value is defined as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities, which are required to be recorded at fair value, we consider the principal or most advantageous market in which we would transact and the market-based risk measurements or assumptions that market participants would use in pricing the asset or liability, such as risks inherent in valuation techniques, transfer restrictions and credit risk. FASB ASC Topic 820, Fair Value Measurement (ASC 820), establishes a fair value hierarchy for instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and our assumptions (unobservable inputs). Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from our independent sources. Unobservable inputs are inputs that reflect our assumptions about the inputs that market participants would use in pricing the asset or liability, and are developed based on the best information available in the circumstances. The following fair value hierarchy is used to classify assets and liabilities based on the observable inputs and unobservable inputs used to value the assets and liabilities: • Level 1: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities; • Level 2: Quoted prices for similar assets and liabilities in active markets, quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability; or • Level 3: Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity). To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Our cash equivalents and marketable securities are reported at fair value determined using Level 1 and Level 2 inputs (Note 6). The fair value of our foreign currency forward contracts is calculated using Level 2 inputs, which include currency spot rates, forward rates, interest rate curve and credit or non-performance risk (Note 7). We do not have any non-financial assets or liabilities that should be recognized or disclosed at fair value on a recurring basis at December 31, 2020, 2019 and 2018. As of December 31, 2020 and 2019, we maintain letters of credit of $12.1 million and $11.8 million, respectively, related to our lease arrangements, which are secured by money market accounts in accordance with certain of our lease agreements. The amounts are recorded at fair value using Level 1 inputs and included as restricted cash in our consolidated balance sheets. Inventory Inventory is recorded at the lower of cost or net realizable value, with cost determined on a first-in, first-out (FIFO) basis. We periodically review the composition of inventory in order to identify excess, obsolete, slow-moving or otherwise unsaleable items. If unsaleable items are observed and there are no alternate uses for the inventory, we will record a write-down to net realizable value in the period that the decline in value is first recognized through a charge to cost of sales. The determination of whether inventory costs will be realizable requires estimates by management. If actual market conditions are less favorable than projected by management, additional write-downs of inventory may be required. Prior to an initial regulatory approval for our investigational medicines, we expense costs relating to raw materials and production of inventory as research and development expense in our consolidated statements of operations, in the period incurred. When we believe regulatory approval and subsequent commercialization of our investigational medicines is probable, and we also expect future economic benefit from the sales of the investigational medicines to be realized, we will then capitalize the costs of production as inventory. Upon the authorization of distribution and use of our COVID-19 vaccine under an EUA in December 2020, we began to capitalize inventory costs associated with our COVID-19 vaccine, as it was determined that inventory costs incurred subsequent to the EUA had a probable future economic benefit. Construction in Progress Construction in progress includes direct costs related to the construction of various property and equipment, including leasehold improvements, and is stated at original cost. Construction in progress includes costs incurred under construction contracts including project management services, engineering services, design services and development, construction services and other construction-related fees and services. Such costs are not depreciated until the asset is completed and placed into service. Once the asset is placed into service, these capitalized costs will be allocated to certain property and equipment categories and will be depreciated over the estimated useful life of the underlying assets. Property and Equipment Property and equipment are stated at cost, net of accumulated depreciation. Depreciation is calculated using the straight-line method over the estimated useful lives of the assets. The estimated useful lives of property and equipment are described below: Estimated Useful Life Laboratory equipment 5 years Leasehold improvements Lesser of estimated useful life of improvement or remaining life of related lease Computer equipment and software 3 years Internally developed software 3 years Furniture, fixtures and other 5 years Right of use asset, financing Lease term Expenditures for maintenance and repairs are charged to expense as incurred. Upon retirement or sale, the cost of the assets disposed of, and the related accumulated depreciation, are removed from the accounts, and any resulting gain or loss is recorded to other (expense) income, net. Impairment of Long-Lived Assets We evaluate our long-lived assets, which consist of property and equipment, to determine if facts and circumstances indicate that the carrying amount of assets may not be recoverable. If such facts and circumstances exist, we assess the recoverability of the long-lived assets by comparing the projected future undiscounted net cash flows associated with the related asset or group of assets over their remaining lives against their respective carrying amounts. If such review indicates that such cash flows are not expected to be sufficient to recover the recorded value of the assets, the assets are written down to their estimated fair values based on the expected discounted future cash flows attributable to the assets or based on appraisals. For the year ended December 31, 2020, we incurred $1.6 million of impairment expenses. We did not record any impairment expenses for the years ended December 31,2019 and 2018. Leases We adopted ASC 842 ( Leases ) on January 1, 2019 on a modified retrospective basis under which we recognized and measured leases existing at, or entered into after, the beginning of the period of adoption. We elected the optional transition approach of not adjusting our comparative period financial statements for the impacts of adoption. Therefore, we recognized the effects of applying ASC 842 as a cumulative-effect adjustment to accumulated deficit as of January 1, 2019, the effective date of this standard. Leases are classified at their commencement date, which is defined as the date on which the lessor makes the underlying asset available for use by the lessee, as either operating or finance leases based on the economic substance of the agreement. We recognize lease right-of-use assets and related liabilities in our consolidated balance sheets for both operating and finance leases. Lease liabilities are measured at the lease commencement date as the present value of the future lease payments using the interest rate implicit in the lease. If the rate implicit is not readily determinable, we will utilize our incremental borrowing rate as of the lease commencement date. Lease right-of-use assets are measured as the lease liability plus initial direct costs and prepaid lease payments less lease incentives. The lease term is the non-cancelable period of the lease and includes options to extend or terminate the lease when it is reasonably certain that an option will be exercised. We recognize operating lease cost in operating expense in our consolidated statements of operations, inclusive of rent escalation provisions and rent holidays, on a straight-line basis over the respective lease term. For our finance leases, we recognize depreciation expense associated with the leased asset acquired and recognize interest expense related to the portion of the financing in our consolidated statements of operations. Additionally, we recognize tenant improvement allowances as a reduction to rent expense on a straight-line basis over the respective lease term. Cost of Sales Cost of sales includes cost of raw materials, production, transportation, freight and indirect overhead costs associated with our product revenue during the period and third-party royalties on net sales of our product. Cost of sales also includes adjustments for excess and obsolete inventory to the extent management determines that the cost cannot be recovered based on estimates about future demand. Research and Development Costs Research and development costs are expensed as incurred. Research and development expenses consist of costs incurred in performing research and development activities, including salaries and benefits, facilities costs, overhead costs, prelaunch inventory costs, contract services, and other outside costs. The value of goods and services received from contract research organizations and contract manufacturing organizations in the reporting period are estimated based on the level of services performed, and progress in the period in cases when we have not received an invoice from the supplier. Equipment or facilities that are acquired or constructed for research and development activities and that have alternative future uses, in research and development projects or otherwise, should be capitalized and depreciated as tangible assets. However, the costs of equipment or facilities that are acquired or constructed and intangibles that are purchased from others for a particular research and development project and that have no alternative future uses and therefore no separate economic values are considered research and development costs and are expensed when incurred. Certain equipment and leased facilities purchased for our COVID-19 vaccine program prior to the EUA from the FDA were deemed to have no alternative use. The related acquisition costs of such equipment and lease facilities of $109.6 million were charged to research and development expense for the year ended December 31, 2020. We did not recognize such expense for the years ended December 31, 2019 or 2018. Patent Costs Costs to secure, defend and maintain patents are expensed as incurred, and are classified as selling, general and administrative expenses due to the uncertainty of future benefits. Stock-Based Compensation We issue stock-based awards to employees and non-employees, generally in the form of stock options and restricted stock units (RSUs). We account for our stock-based compensation awards in accordance with ASC 718, Compensation—Stock Compensation . Most of our stock-based awards have been made to employees. We measure compensation cost for equity awards at their grant-date fair value and recognize compensation expense over the requisite service period, which is generally the vesting period, on a straight-line basis. The grant date fair value of stock options is estimated using the Black-Scholes option pricing model, which requires management to make assumptions with respect to the fair value of our common stock on the grant date, including the expected term of the award, the expected volatility of our stock, calculated based on a period of time generally commensurate with the expected term of the award, risk-free interest rates and expected dividend yields of our stock. Historically, for periods prior to our IPO, the fair value of the shares of common stock and common units underlying our stock-based awards were determin

Grant Revenue

Grant Revenue	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Grants	Grant Revenue In September 2020, we entered into an agreement with the Defense Advanced Research Projects Agency (DARPA) for an award of up to $56.4 million to fund development of a mobile manufacturing prototype leveraging our existing manufacturing technology that is capable of rapidly producing vaccines and therapeutics. As of December 31, 2020, the committed funding, net of revenue earned was $4.6 million, with an additional $51.4 million available if DARPA exercises additional contract options. In April 2020, we entered into an agreement with BARDA for an award of up to $483.3 million to accelerate development of mRNA-1273, our vaccine candidate against COVID-19. In July 2020, we amended our agreement with BARDA to provide for an additional commitment of up to $471.6 million to support late-stage clinical development of mRNA-1273, including the execution of a 30,000 participant Phase 3 study in the U.S. The amendment increased the maximum award from BARDA from $483.3 million to $954.9 million. Under the terms of the agreement, BARDA will fund the advancement of mRNA-1273 to FDA licensure. All contract options have been exercised. As of December 31, 2020, the remaining available funding net of revenue earned was $444.3 million. In September 2016, we received an award of up to $125.8 million from BARDA, to help fund our Zika vaccine program. Three of the four contract options have been exercised. As of December 31, 2020, the remaining available funding net of revenue earned was $70.8 million, with an additional $8.4 million available if the final contract option is exercised. In January 2016, we entered a global health project framework agreement with the Gates Foundation to advance mRNA-based development projects for various infectious diseases, including human immunodeficiency virus (HIV). As of December 31, 2020, the available funding net of revenue earned was $11.4 million, with up to an additional $80.0 million available if additional follow-on projects are approved. The following tables summarize grant revenue and deferred grant revenue for and as of the periods presented (in thousands): Years Ended 2020 2019 2018 BARDA $ 521,652 $ 7,608 $ 6,736 Other grant revenue 7,253 4,565 5,820 Total grant revenue $ 528,905 $ 12,173 $ 12,556 December 31, 2020 2019 Deferred grant revenue $ 5,261 $ 2,777 In December 2020, we began selling our COVID-19 vaccine to the U.S. Government and international government agencies. Under the supply agreements with these government agencies, we received or billed for upfront deposits for our future vaccine supply, which are initially recorded as deferred revenue. We recognize revenue based on the fixed price per dose when control of the product has transferred and customer acceptance has occurred, unless such acceptance provisions are deemed perfunctory. Product sales by customer geographic location was as follows (in thousands): Year Ended December 31, 2020 United States $ 193,630 Rest of world 6,242 Total $ 199,872 There were no product sales in 2019 and 2018. We had one commercial product, our COVID-19 vaccine, authorized for use as of December 31, 2020. Geographic Revenue We operate in one reporting segment that primarily focuses on the discovery, development and commercialization of mRNA medicines. Our chief executive officer manages our operations and evaluates our financial performance on a consolidated basis. Most of our principal operations, other than manufacturing, and our decision-making functions are located at our corporate headquarters in the United States. Total revenue by geographic area of our customers and collaboration partners was as follows (in thousands): Years Ended December 31, 2020 2019 2018 United States $ 764,529 $ 54,976 $ 89,075 Rest of world 38,866 5,233 45,993 Total $ 803,395 $ 60,209 $ 135,068 Our property and equipment, including financing right-of-use asset, were principally located within the United States as of December 31, 2020 and 2019.

Product Sales

Product Sales	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Product Sales	Grant Revenue In September 2020, we entered into an agreement with the Defense Advanced Research Projects Agency (DARPA) for an award of up to $56.4 million to fund development of a mobile manufacturing prototype leveraging our existing manufacturing technology that is capable of rapidly producing vaccines and therapeutics. As of December 31, 2020, the committed funding, net of revenue earned was $4.6 million, with an additional $51.4 million available if DARPA exercises additional contract options. In April 2020, we entered into an agreement with BARDA for an award of up to $483.3 million to accelerate development of mRNA-1273, our vaccine candidate against COVID-19. In July 2020, we amended our agreement with BARDA to provide for an additional commitment of up to $471.6 million to support late-stage clinical development of mRNA-1273, including the execution of a 30,000 participant Phase 3 study in the U.S. The amendment increased the maximum award from BARDA from $483.3 million to $954.9 million. Under the terms of the agreement, BARDA will fund the advancement of mRNA-1273 to FDA licensure. All contract options have been exercised. As of December 31, 2020, the remaining available funding net of revenue earned was $444.3 million. In September 2016, we received an award of up to $125.8 million from BARDA, to help fund our Zika vaccine program. Three of the four contract options have been exercised. As of December 31, 2020, the remaining available funding net of revenue earned was $70.8 million, with an additional $8.4 million available if the final contract option is exercised. In January 2016, we entered a global health project framework agreement with the Gates Foundation to advance mRNA-based development projects for various infectious diseases, including human immunodeficiency virus (HIV). As of December 31, 2020, the available funding net of revenue earned was $11.4 million, with up to an additional $80.0 million available if additional follow-on projects are approved. The following tables summarize grant revenue and deferred grant revenue for and as of the periods presented (in thousands): Years Ended 2020 2019 2018 BARDA $ 521,652 $ 7,608 $ 6,736 Other grant revenue 7,253 4,565 5,820 Total grant revenue $ 528,905 $ 12,173 $ 12,556 December 31, 2020 2019 Deferred grant revenue $ 5,261 $ 2,777 In December 2020, we began selling our COVID-19 vaccine to the U.S. Government and international government agencies. Under the supply agreements with these government agencies, we received or billed for upfront deposits for our future vaccine supply, which are initially recorded as deferred revenue. We recognize revenue based on the fixed price per dose when control of the product has transferred and customer acceptance has occurred, unless such acceptance provisions are deemed perfunctory. Product sales by customer geographic location was as follows (in thousands): Year Ended December 31, 2020 United States $ 193,630 Rest of world 6,242 Total $ 199,872 There were no product sales in 2019 and 2018. We had one commercial product, our COVID-19 vaccine, authorized for use as of December 31, 2020. Geographic Revenue We operate in one reporting segment that primarily focuses on the discovery, development and commercialization of mRNA medicines. Our chief executive officer manages our operations and evaluates our financial performance on a consolidated basis. Most of our principal operations, other than manufacturing, and our decision-making functions are located at our corporate headquarters in the United States. Total revenue by geographic area of our customers and collaboration partners was as follows (in thousands): Years Ended December 31, 2020 2019 2018 United States $ 764,529 $ 54,976 $ 89,075 Rest of world 38,866 5,233 45,993 Total $ 803,395 $ 60,209 $ 135,068 Our property and equipment, including financing right-of-use asset, were principally located within the United States as of December 31, 2020 and 2019.

Collaboration Agreements

Collaboration Agreements	12 Months Ended
	Dec. 31, 2020
Research and Development [Abstract]
Collaboration Agreements	Collaboration Agreements The following table summarizes our total consolidated net revenue from our strategic collaborators for the periods presented (in thousands): Years Ended December 31, Collaboration Revenue by Strategic Collaborator: 2020 2019 2018 (1) Merck $ 26,076 $ 36,608 $ 66,082 AstraZeneca 32,624 5,233 45,993 Vertex 15,505 6,195 10,437 Other 413 — — Total collaboration revenue $ 74,618 $ 48,036 $ 122,512 ________ (1) Under ASC 605 The following table presents changes in the balances of our receivables and contract liabilities related to our strategic collaboration agreements during the year ended December 31, 2020 (in thousands): December 31, 2019 Additions Deductions December 31, 2020 Contract Assets: Accounts receivable $ 1,972 $ 120,821 $ (117,249) $ 5,544 Contract Liabilities: Deferred revenue $ 199,528 $ 121,882 $ (81,228) $ 240,182 During the year ended December 31, 2020, we recognized the following revenue as a result of the change in the contract liability balances related to our collaboration agreements (in thousands): Revenue recognized in the period from: Year Ended Amounts included in contract liabilities at the beginning of the period (1) $ 72,863 Performance obligations satisfied (or partially satisfied) in previous reporting periods (2) 8,366 ______________ (1) We first allocate revenue to the individual contract liability balance outstanding at the beginning of the period until the revenue exceeds that balance. If additional consideration is received on those contracts in subsequent periods, we assume all revenue recognized in the reporting period first applies to the beginning contract liability. (2) Related to changes in estimated costs for our future performance obligations and estimated variable considerations. As of December 31, 2020, the aggregated amount of the transaction price allocated to performance obligations under our collaboration agreements that are unsatisfied or partially unsatisfied was $327.7 million. AstraZeneca – Strategic Alliances in Cardiovascular and Oncology 2013 Option Agreement and Services and Collaboration Agreement In March 2013, we entered into an Option Agreement, the AZ Option Agreement, and a related Services and Collaboration Agreement, the AZ Services Agreement, with AstraZeneca, which were amended and restated in June 2018. We refer to these agreements in the forms that existed prior to the 2018 amendment and restatement as the 2013 AZ Agreements. Under the 2013 AZ Agreements, we granted AstraZeneca certain exclusive rights and licenses, and options to obtain exclusive rights to develop and commercialize potential therapeutic mRNA medicines directed at certain targets for the treatment of cardiovascular and cardiometabolic diseases and cancer, and agreed to provide related services to AstraZeneca. Pursuant to the 2013 AZ Agreements, AstraZeneca was responsible for all research, development and commercialization activities, while we provided specified research and manufacturing services during a research and evaluation period, as described below, to further AstraZeneca’s activities pursuant to an agreed upon services plan. Under the 2013 AZ Agreements, AstraZeneca could have requested we provide additional services, at AstraZeneca’s expense. Subject to customary “back-up” supply rights granted to AstraZeneca, we exclusively manufactured (or had manufactured) mRNA for all research, development and commercialization purposes under the 2013 AZ Agreements until, on a product-by-product basis, the expiration of the time period for which we are entitled to receive earn-out payments with respect to such product pursuant to the 2013 AZ Agreements. As of the effective date of the 2013 AZ Agreements, AstraZeneca acquired forty options that it may exercise to obtain exclusive rights to clinically develop and commercialize identified development candidates (and related back-up candidates) directed to specified targets that arise during the research and evaluation period. During the research and evaluation period for research candidates under the 2013 AZ Agreements, AstraZeneca could have elected to designate a limited number of research candidates as development candidates in order to continue preclinical development on such development candidates (and related back-up candidates). From such pool of development candidates designated by AstraZeneca, during a specified option exercise period, AstraZeneca could have then exercised one of its options to obtain exclusive rights to clinically develop and commercialize an identified development candidate (and related back-up candidates). If AstraZeneca did not exercise one of its options to acquire exclusive rights to clinically develop and commercialize a particular development candidate during the defined option exercise period for such development candidate, AstraZeneca’s rights to exercise an option and other rights granted under the 2013 AZ Agreements with respect to such development candidate (and related back-up candidates) would terminate, all rights to exploit such development candidate (and related back-up candidates) would be returned to us and all data and results generated by AstraZeneca with respect to such development candidate (and related back-up candidates) would be either assigned or licensed to us. Upon the earlier of termination of the 2013 AZ Agreements for any reason and a specified anniversary of the effective date of the 2013 AZ Agreements, all exercised options, and the right to exercise any and all options if not previously exercised by AstraZeneca, would automatically terminate. On a target-by-target basis, we and AstraZeneca agreed to certain defined exclusivity obligations under the 2013 AZ Agreements with respect to the research, development and commercialization of mRNA medicines for such target. As of the effective date of the 2013 AZ Agreements, AstraZeneca made upfront cash payments to us totaling $240.0 million. Under the 2013 AZ Agreements, we were entitled to receive payments that are not related to any specific program of up to $180.0 million in the aggregate for the achievement of three technical milestones relating to toxicity, delivery, and competition criteria. We achieved the toxicity and competition milestones in the year ended December 31, 2015. The delivery milestone has expired. Under the 2013 AZ Agreements, AstraZeneca was obligated to pay us a $10.0 million option exercise fee with respect to each development candidate (and related back-up candidates) for which it exercised an option. In addition, upon AstraZeneca’s exercise of each option, we were eligible to receive certain payments contingent upon the achievement of specified clinical, regulatory, and commercial events. For any product candidate optioned by AstraZeneca, we were eligible to receive, per product candidate, up to $100.0 million in payments for achievement of development milestones, up to $100.0 million payments for achievement of regulatory milestones, and up to $200.0 million payments for achievement of commercial milestones. Additionally, under the 2013 AZ Agreements, we were entitled to receive, on a product-by-product basis, earn-out payments on worldwide net sales of products ranging from a high-single digit percentage to 12%, subject to certain reductions, with an aggregate minimum floor. We received from AstraZeneca under the 2013 AZ Agreements an option exercise payment of $10.0 million (the 2016 VEGF Exercise) in the year ended December 31, 2016, and a clinical milestone payment of $30.0 million with respect to AstraZeneca’s VEGF-A product (AZD8601) during the year ended December 31, 2018, that is currently being developed in a Phase 2 clinical trial. Unless earlier terminated, the 2013 AZ Agreements would have continued until the expiration of AstraZeneca’s earn-out and contingent option exercise payment obligations for optioned product candidates. Either party had the right to terminate the 2013 AZ Agreements upon the other party’s material breach, either in its entirety or in certain circumstances, with respect to relevant candidates, subject to a defined materiality threshold and specified notice and cure provisions. If AstraZeneca had the right to terminate the 2013 AZ Agreements for our material breach, then AstraZeneca could have elected, in lieu of terminating the 2013 AZ Agreements, in their entirety or with respect to such candidates, to have the 2013 AZ Agreements remain in effect, subject to reductions in certain payments we were eligible to receive and certain adjustments to AstraZeneca’s obligations under the 2013 AZ Agreements. AstraZeneca had the right to terminate the 2013 AZ Agreements in full, without cause, upon 90-days’ prior notice to us. 2016 Strategic Alliance with AstraZeneca – IL-12 In January 2016, we entered into a new Strategic Drug Development Collaboration and License Agreement, which we refer to as the 2016 AZ Agreement, with AstraZeneca to discover, develop and commercialize potential mRNA medicines for the treatment of a range of cancers. Under the terms of the 2016 AZ Agreement, we and AstraZeneca have agreed to work together on an immuno-oncology program focused on the intratumoral delivery of a potential mRNA medicine to make the IL-12 protein. The 2016 AZ Agreement initially included research activities with respect to a second discovery program. During a limited period of time, each party had an opportunity to propose additional discovery programs to be conducted under the 2016 AZ Agreement. We are responsible for conducting and funding all discovery and preclinical development activities under the 2016 AZ Agreement in accordance with an agreed upon discovery program plan for the IL-12 program and any other discovery program the parties agree to conduct under the 2016 AZ Agreement. For the IL-12 program and any other discovery program the parties agree to conduct under the 2016 AZ Agreement, during a defined election period that commenced as of the effective date of the 2016 AZ Agreement (for the IL-12 program) and otherwise will commence on initiation of any such new discovery program, AstraZeneca may elect to participate in the clinical development of a development candidate arising under the 2016 AZ Agreement from such program. If AstraZeneca so elects (as it has for the IL-12 program), AstraZeneca will lead clinical development activities worldwide and we will be responsible for certain activities, including being solely responsible for manufacturing activities, all in accordance with an agreed upon development plan. AstraZeneca will be responsible for funding all Phase 1 clinical development activities (including costs associated with our manufacture of clinical materials in accordance with the development plan), and Phase 2 clinical development activities (including costs associated with our manufacture of clinical materials in accordance with the development plan) up to a defined dollar threshold. We and AstraZeneca will equally share the costs of Phase 2 clinical development activities in excess of such dollar threshold, all Phase 3 clinical development activities and certain other costs of late-stage clinical development activities, unless we elect not to participate in further development and commercialization activities and instead receive tiered royalties, as described below. We and AstraZeneca will co-commercialize products in the U.S. in accordance with an agreed upon commercialization plan and budget, and on a product-by-product basis will equally share the U.S. profits or losses arising from such commercialization. Notwithstanding, on a product-by-product basis, prior to a specified stage of development of a given product, we have the right to elect not to participate in the further development and commercialization activities for such product. If we make such election, instead of participating in the U.S. profits and losses share with respect to such product, we are obligated to discuss future financial terms with AstraZeneca. If we are unable to agree on future financial terms within a short, defined period of time, we are entitled to receive tiered royalties at default rates set forth in the 2016 AZ Agreement, ranging from percentages in the mid-single digits to 20% on worldwide net sales of products, subject to certain reductions with an aggregate minimum floor. AstraZeneca has sole and exclusive responsibility for all ex-U.S. commercialization efforts. Unless we have elected to not to participate in further development (in which case royalties on ex-U.S. net sales will be at the default rates as described above, unless otherwise agreed by the parties), we are entitled to tiered royalties at rates ranging from 10% to 30% on ex-U.S. net sales of the products, subject to certain reductions with an aggregate minimum floor. Subject to customary “back-up” supply rights granted to AstraZeneca, we exclusively manufacture (or have manufactured) products for all development and commercialization purposes. We and AstraZeneca have agreed to certain defined exclusivity obligations with each other under the 2016 AZ Agreement with respect to the development and commercialization of mRNA medicines for IL-12. Unless earlier terminated, our strategic alliance under the 2016 AZ Agreement will continue on a product-by-product basis (i) until both parties cease developing and commercializing such product without the intention to resume, if we have not elected our right not to participate in further development and commercialization of such product or (ii) on a country-by-country basis, until the end of the applicable royalty term for such product in such country, if we have elected our right not to participate in further development and commercialization of such product. Either party may terminate the 2016 AZ Agreement upon the other party’s material breach, subject to specified notice and cure provisions. Each party may also terminate the 2016 AZ Agreement in the event the other party challenges such party’s patent rights, subject to certain defined exceptions. AstraZeneca has the right to terminate the 2016 AZ Agreement in full or with respect to any program for scientific, technical, regulatory or commercial reasons at any time upon 90 days’ prior written notice to us. On a product-by-product basis, we have the right to terminate the 2016 AZ Agreement in certain cases if AstraZeneca has suspended or is no longer proceeding with the development or commercialization of such product for a period of twelve If we continue developing and commercializing a given product following termination of the 2016 AZ Agreement by AstraZeneca in its discretion with respect to such product, AstraZeneca is entitled to receive a mid-single digit royalty on our worldwide net sales of such product and a high-single digit percentage of the amounts received by us from a third party in consideration of a license to such third party to exploit such product, in each case, until AstraZeneca recovers an amount equal to specified development costs incurred by AstraZeneca under the 2016 AZ Agreement with respect to such product prior to such termination. Such percentages increase by a low to mid-single digit amount to the extent such termination occurs after such product achieves a specified stage of development. 2013 Agreements with AstraZeneca, amended and restated in 2018 In June 2018, we entered into an Amended and Restated Option Agreement and a related Amended and Restated Services and collaboration Agreement with AstraZeneca, or the 2018 A&R Agreements, which amended and restated the 2013 AZ Agreements. Under the 2018 A&R Agreements, we granted AstraZeneca certain exclusive rights and licenses to research, develop and commercialize potential therapeutic mRNA medicines directed at certain targets for the treatment of cardiovascular and cardiometabolic diseases and cancer, and agreed to provide related services to AstraZeneca. The activities to be performed by the parties under the 2018 A&R Agreements are limited to defined biological targets in the cardiovascular and cardiometabolic fields and one defined target in the cancer field. Pursuant to the 2018 A&R Agreements, AstraZeneca is responsible for all research, development and commercialization activities and associated costs, while we provide specified research and manufacturing services during a research and evaluation period, as described below, to further AstraZeneca’s activities conducted pursuant to an agreed upon services plan. During this research and evaluation period, these research services, and manufacturing services in excess of a specified threshold, are provided at AstraZeneca’s expense, and manufacturing services below the specified threshold are provided at no additional expense to AstraZeneca. AstraZeneca may request we provide additional research and manufacturing services, at AstraZeneca’s expense, following the end of the research and evaluation period. Subject to customary “back-up” supply rights granted to AstraZeneca, we exclusively manufacture (or have manufactured) mRNA for all research, development and commercialization purposes under the 2018 A&R Agreements until, on a product-by-product basis, the expiration of the time period for which we are entitled to receive earn-out payments with respect to such product pursuant to the 2018 A&R Agreements. As of the effective date of the 2013 AZ Agreements, and as further reflected in the 2018 A&R Agreements, AstraZeneca acquired forty options that it may exercise to obtain exclusive rights to clinically develop and commercialize identified development candidates (and related back-up candidates) directed to specified targets that arise during the research and evaluation period. During the research and evaluation period for research candidates, AstraZeneca may elect to designate a limited number of research candidates as development candidates in order to continue preclinical development on such development candidates (and related back-up candidates). From such pool of development candidates designated by AstraZeneca, during a specified option exercise period, AstraZeneca may then exercise one of its options to obtain exclusive rights to clinically develop and commercialize an identified development candidate (and related back-up candidates) in certain fields. If AstraZeneca does not exercise one of its options to acquire exclusive rights to clinically develop and commercialize a particular development candidate during the defined option exercise period for such development candidate, AstraZeneca’s rights to exercise an option and other rights granted under the 2018 A&R Agreements with respect to such development candidate (and related back-up candidates) will terminate, all rights to exploit such development candidate (and related back-up candidates) will be returned to us and all data and results generated by AstraZeneca with respect to such development candidate (and related back-up candidates) will be either assigned or licensed to us. Upon the earlier of termination of the 2018 A&R Agreements for any reason and a specified anniversary of the effective date of the 2013 AZ Agreements, all unexercised options, and the right to exercise any and all options if not previously exercised by AstraZeneca, will automatically terminate. On a target-by-target basis, we and AstraZeneca have agreed to certain defined exclusivity obligations under the 2018 A&R Agreements with respect to the research, development and commercialization of mRNA medicines for such target in certain fields. In addition, we and AstraZeneca have agreed to certain defined exclusivity obligations with respect to the research, development and commercialization of mRNA medicines coding for the same polypeptide as any development candidate being developed under the 2018 A&R Agreements. Unless earlier terminated, the 2018 A&R Agreements will continue until the expiration of AstraZeneca’s earn-out and contingent option exercise payment obligations for optioned product candidates. Either party may terminate the 2018 A&R Agreements upon the other party’s material breach, either in its entirety or in certain circumstances, with respect to relevant candidates, subject to a defined materiality threshold and specified notice and cure provisions. If AstraZeneca has the right to terminate the 2018 A&R Agreements for our material breach, then AstraZeneca may elect, in lieu of terminating the 2018 A&R Agreements, in their entirety or with respect to such candidates, to have the 2018 A&R Agreements remain in effect, subject to reductions in certain payments we are eligible to receive and certain adjustments to AstraZeneca’s obligations under the 2018 A&R Agreements. AstraZeneca may terminate the 2018 A&R Agreements in full, without cause, upon 90 days’ prior notice to us. Accounting Treatment Combined 2018 AZ Agreements The 2013 Agreements, as amended by the 2018 A&R Agreements, and the 2016 AZ Agreement, referred to as the Combined 2018 AZ Agreements, are treated as a single agreement for accounting purposes as these agreements were negotiated in contemplation of each other. The Combined 2018 AZ Agreements represent a transaction with a customer and therefore is accounted for in accordance with ASC 606. We identified the following performance obligations in the Combined 2018 AZ Agreements: (i) a combined performance obligation that includes a research license, research and development pool services, and manufacturing obligations related to the 2013 AZ Agreements, as amended by the 2018 A&R Agreements, collectively referred to as the Combined 2018 AZ Agreement Performance Obligation, (ii) preclinical development services for IL-12, (iii) preclinical development services for an oncology development target, (iv) a combined performance obligation for a development and commercialization license and manufacturing obligations for IL-12, and (v) a material right to receive development and commercialization rights and manufacturing services for an oncology development target. We concluded that the research license is not distinct from the research and development pool services or the manufacturing obligations related to the 2018 A&R Agreements, as AstraZeneca cannot fully exploit the value of the research license without receipt of such services and supply. Our services and supply involve specialized expertise, particularly as it relates to mRNA technology that is not available in the marketplace. Any supply requested by AstraZeneca in excess of the minimum quantities specified in the agreement are considered customer options and treated as separate contracts for accounting purposes. Further, we concluded that AstraZeneca cannot exploit the value of the development and commercialization license for IL-12 without receipt of supply as the development and commercialization license does not convey to AstraZeneca the right to manufacture and therefore combined the development and commercialization license and the manufacturing obligations for IL-12 into one performance obligation. The following table summarizes the composition of the total transaction price for the periods presented (in thousands): Transaction Price December 31, Combined 2018 AZ Agreements: 2020 2019 Upfront payments $ 240,000 $ 240,000 Sublicense reimbursement 1,000 1,000 Toxicity milestone payment 60,000 60,000 Competition milestone payment 60,000 60,000 Estimated reimbursement for IL-12 manufacturing obligations 35,830 40,782 Total $ 396,830 $ 401,782 We utilize the most likely amount method to determine the amount of reimbursement for IL-12 manufacturing obligations to be received. We determined that any sales-based royalties related to IL-12 will be recognized when the related sales occur as they were determined to relate predominately to the license granted and therefore have been excluded from the transaction price. In addition, we are eligible to receive future milestones and royalties on future commercial sales for optioned product candidates under the 2018 A&R Agreements and future royalties under the 2016 Agreement; however, these amounts are not considered variable consideration under the Combined 2018 Agreements as we are only eligible to receive such amounts if AstraZeneca exercises its options (including certain options that are deemed to be material rights). We have concluded that the exercise of an optioned product candidate represents a separate transaction under ASC 606. We re-evaluate the transaction price at the end of each reporting period. There was a $5.0 million d ecrease to the transaction price during the year ended December 31, 2020, resulting from a change in estimate of variable consideration. The transaction price was allocated to the performance obligations based on the relative estimated standalone selling prices of each performance obligation. We developed the estimated standalone selling price for the licenses included in the Combined 2018 AZ Agreement Performance Obligation and the combined performance obligation for a development and commercialization license and manufacturing obligations for IL-12 primarily based on the probability-weighted present value of expected future cash flows associated with each license related to each specific program. In developing such estimate, we also considered applicable market conditions and relevant entity-specific factors, including those factors contemplated in negotiating the agreement, probability of success and the time needed to commercialize a product candidate pursuant to the associated license. We developed the estimated standalone selling price for the services and/or manufacturing and supply included in each of the performance obligation, as applicable, primarily based on the nature of the services to be performed and/or goods to be manufactured and estimates of the associated costs, adjusted for a reasonable profit margin that would be expected to be realized under similar contracts. The estimated standalone selling price of the material right to receive development and commercialization rights and manufacturing services for an oncology development target was developed by estimating the amount of discount that AstraZeneca would receive when exercising the option and adjusting such amount by the likelihood that the option will be exercised. The following table summarizes the allocation of the total transaction price to the identified performance obligations under the arrangement, and the amount of the transaction price unsatisfied as of December 31, 2020 (in thousands): Transaction Price Combined 2018 AZ Agreements: December 31, 2020 Combined 2018 AZ Agreement performance obligation $ 293,223 Preclinical development service - IL-12 8,133 Preclinical development service - oncology development target 8,133 Development and commercialization license and manufacturing obligation 85,750 Material right to receive development and commercialization rights 1,591 Total $ 396,830 Remaining unsatisfied performance obligation $ 87,225 As of December 31, 2020, $77.5 million of the remaining performance obligations that are unsatisfied is expected to be recognized as revenue through December 31, 2029 and $9.7 million is expected to be recognized as revenue at the earlier of expiration or modification of the Combined 2018 AZ Agreement. We measure proportional performance over time using an input method based on cost incurred relative to the total estimated costs for the Combined 2018 AZ Agreement Performance Obligation and the preclinical development services for IL-12 and the other oncology target performance obligations. We recognize revenue related to the amounts allocated to the combined performance obligation for a development and commercialization license and manufacturing obligations for IL-12 based on the point in time upon which control of supply is transferred to AstraZeneca for each delivery of the associated supply. We recognize revenue for the Combined 2018 AZ Agreement Performance Obligation by determining the proportion of effort incurred as a percentage of total effort we expect to expend. This ratio is applied to the transaction price allocated to this combined performance obligation. We also estimate the development plan, including expected demand from AstraZeneca, and the associated costs for this combined performance obligation, as we will satisfy this combined performance obligation as the manufacturing services are performed. Management has applied significant judgment in the process of developing our budget estimates. Any changes to these estimates will be recognized in the period in which they change as a cumulative catch up. The following table summarizes the revenue recognized for the periods presented (in thousands): Years Ended December 31, 2020 2019 2018 Combined AZ Agreements $ 18,371 $ 4,650 $ 45,393 The revenue recognized for the year ended December 31, 2020 includes the amortization of deferred revenue due to the satisfaction of our performance obligation during the period, including a cumulative catch-up adjustment of $12.5 million due to changes in estimated costs for our future performance obligations. The following table summarizes the balances of deferred revenue at period end, which is classified as current or non-current in the consolidated balance sheets based on the period the services are expected to be performed or control of the supply is expected to be transferred (in thousands): December 31, 2020 2019 Combined AZ Agreements $ 57,192 $ 73,669 2016 VEGF Exercise We concluded that the 2016 VEGF Exercise should be treated as a separate transaction for accounting purposes, represents a transaction with a customer and therefore is accounted for in accordance with ASC 606. We identified one performance obligation in this arrangement which is comprised of the exclusive license to develop and commercialize VEGF and the manufacturing of clinical supply. We concluded that the VEGF license is not distinct from the manufacturing obligations because AstraZeneca cannot fully exploit the value of the license without receipt of such supply. This is due to limitations inherent in the licenses conveyed wherein AstraZeneca does not have the contractual right to manufacture during the term of the agreement. The following table summarizes the composition of the total transaction price for the periods presented (in thousands): Transaction Price December 31, 2016 VEGF Exercise: 2020 2019 Option exercise fee $ 10,000 $ 10,000 Milestone payment 30,000 30,000 Sublicense reimbursement 2,250 2,250 Estimated reimbursement for clinical supply 18,062 15,621 Total $ 60,312 $ 57,871 We are eligible to receive future milestones and royalties on future commercial sales under this arrangement. We utilize the most likely amount method to estimate any development and regulatory milestone payments to be received and the amount of estimated reimbursement for clinical supply. As of December 31, 2020, there were no milestones that had not been achieved included in the transaction price. We considered the stage of development and the risks associated with the remaining development required to achieve each milestone, as well as whether the achievement of the milestone is outside of our or AstraZeneca’s control. The outstanding milestone payments were fully constrained, as a result of the uncertainty whether any of the milestones would be achieved. We determined that any commercial milestones and sales-based royalties will be recognized when the related sales occur as they were determined to relate predominantly to the license granted and therefore have also been excluded from the transaction price. We re-evaluate the transaction price at the end of each reporting period and as uncertain events are resolved or other changes in circumstances occur. When a milestone payment is included in the transaction price in the future, it is recognized as revenue based on the relative completion of the underlying performance obligation. There was a $2.4 million increase to the transaction price during the year ended December 31, 2020, resulting from a change in estimate of variable consideration. The following table summarizes the total transaction price allocated to the single performance obligation under the arrangement, and the amount of the transaction price unsatisfied as of December 31, 2020 (in thousands): Transaction Price December 31, 2020 2016 VEGF Exercise combined performance obligation 60,312 Remaining unsatisfied performance obligation 41,877 As of December 31, 2020, the remaining performance obligations that are unsatisfied is expected to be recognized as revenue through December 31, 2025. We recognize re

Financial Instruments and Fair

Financial Instruments and Fair Value Measurements	12 Months Ended
	Dec. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Financial Instruments and Fair Value Measurements	Financial Instruments and Fair Value Measurements Cash and Cash Equivalents and Investments The following tables summarize our cash and available-for-sale securities by significant investment category at December 31, 2020 and 2019 (in thousands): December 31, 2020 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Cash and Cash Equivalents Current Marketable Securities Non- Current Marketable Securities Cash and cash equivalents $ 2,623,849 $ 1 $ — $ 2,623,850 $ 2,623,850 $ — $ — Available-for-sale: Certificates of deposit 238,774 49 (4) 238,819 — 215,389 23,430 U.S. treasury securities 491,549 69 — 491,618 — 491,618 — Debt securities of U.S. government agencies and corporate entities 1,888,022 4,294 (147) 1,892,169 — 1,276,751 615,418 $ 5,242,194 $ 4,413 $ (151) $ 5,246,456 $ 2,623,850 $ 1,983,758 $ 638,848 December 31, 2019 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Cash and Cash Equivalents Current Marketable Securities Non- Current Marketable Securities Cash and cash equivalents $ 225,874 $ — $ — $ 225,874 $ 225,874 $ — $ — Available-for-sale: Certificates of deposit 82,028 79 (6) 82,101 10,002 69,197 2,902 U.S. treasury securities 117,891 260 (2) 118,149 — 110,186 7,963 Debt securities of U.S. government agencies and corporate entities 834,187 2,708 (32) 836,863 — 687,741 149,122 $ 1,259,980 $ 3,047 $ (40) $ 1,262,987 $ 235,876 $ 867,124 $ 159,987 The amortized cost and estimated fair value of marketable securities, by contractual maturity at December 31, 2020 and 2019 are as follows (in thousands): December 31, 2020 Amortized Cost Estimated Fair Value Due in one year or less $ 1,980,963 $ 1,983,758 Due after one year through five years 637,382 638,848 Total $ 2,618,345 $ 2,622,606 December 31, 2019 Amortized Cost Estimated Fair Value Due in one year or less $ 864,958 $ 867,124 Due after one year through five years 159,148 159,987 Total $ 1,024,106 $ 1,027,111 In accordance with our investment policy, we place investments in investment grade securities with high credit quality issuers, and generally limit the amount of credit exposure to any one issuer. We evaluate securities for impairment at the end of each reporting period. We did not record any impairment charges related to our available-for-sale securities during the years ended December 31, 2020, 2019 and 2018. We did not recognize any credit losses related allowance to available-for-sale securities as of the years ended December 31, 2020 and 2019. The following table summarizes the amount of gross unrealized losses and the estimated fair value for our available-for-sale securities in an unrealized loss position by length of time the securities have been in an unrealized loss position at December 31, 2020 and 2019 (in thousands): Less than 12 Months 12 Months or More Total Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value As of December 31, 2020: Certificates of deposit $ (4) $ 81,524 $ — $ — $ (4) $ 81,524 Debt securities of U.S. government agencies and corporate entities (148) 507,016 — — (148) 507,016 Total $ (152) $ 588,540 $ — $ — $ (152) $ 588,540 As of December 31, 2019: Certificates of deposit $ (6) $ 12,822 $ — $ — $ (6) $ 12,822 U.S. treasury securities (2) 9,979 — — (2) 9,979 Debt securities of U.S. government agencies and corporate entities (32) 62,360 — — (32) 62,360 Total $ (40) $ 85,161 $ — $ — $ (40) $ 85,161 At December 31, 2020 and 2019, we held 108 and 19 individual available-for-sale securities, respectively, out of our total investment portfolio that were in a continuous unrealized loss position for less than 12 months. We neither intend to sell these investments nor conclude that we are more-likely-than-not that we will have to sell them before recovery of their carrying values. We also believe that we will be able to collect both principal and interest amounts due to us at maturity. Assets and Liabilities Measured at Fair Value on a Recurring Basis The following tables summarize our financial assets measured at fair value on a recurring basis as of December 31, 2020 and 2019 (in thousands): Fair Value at December 31, 2020 Fair Value Measurement Using Level 1 Level 2 Assets: Money market funds $ 620,947 $ 620,947 $ — Certificates of deposit 238,819 — 238,819 U.S. treasury securities 491,618 — 491,618 Debt securities of U.S. government agencies and corporate entities 1,892,169 — 1,892,169 Derivative instruments (Note 7) 293 — 293 Total $ 3,243,846 $ 620,947 $ 2,622,899 Fair Value at December 31, 2019 Fair Value Measurement Using Level 1 Level 2 Assets: Certificates of deposit $ 82,101 $ — $ 82,101 U.S. treasury securities 118,149 — 118,149 Debt securities of U.S. government agencies and corporate entities 836,863 — 836,863 Total $ 1,037,113 $ — $ 1,037,113 During the years ended December 31, 2020 and 2019, we did not have any financial liabilities measured at fair value on a recurring basis and did not have non-financial assets or liabilities measured at fair value on a recurring basis.

Derivative Financial Instrument

Derivative Financial Instruments	12 Months Ended
	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments We transact business in various foreign currencies and have international sales and expenses denominated in foreign currencies. Therefore, we are exposed to certain risks arising from both our business operations and economic conditions. Our risk management strategy includes the use of derivative financial instruments to hedge foreign currency exchange rate fluctuations on monetary assets or liabilities denominated in foreign currencies. We do not enter into derivative financial contracts for speculative or trading purposes. We do not believe that we are exposed to more than a nominal amount of credit risk in our foreign currency hedges, as counterparties are large, global and well-capitalized financial institutions. We classify cash flows from our derivative transactions as cash flows from operating activities in our consolidated statements of cash flows. Balance Sheet Hedges Our foreign currency forward contracts, primarily accounts receivable, are not designated for hedge accounting treatment. Therefore, these forward contracts are accounted for as derivatives whereby the fair value of the contracts are reported as other current assets or other current liabilities on our consolidated balance sheets, and gains and losses resulting from changes in the fair value are recorded as a component of other (expense) income, net, in our consolidated statements of operations. The gains and losses on these foreign currency forward contracts generally offset the gains and losses in the underlying foreign currency denominated assets and liabilities, which are also recorded to other (expense) income, net, in our consolidated statements of operations. Total gross notional amount and fair value for foreign currency derivatives that are not designated as hedging instruments are accounted for as follows (in thousands): December 31, 2020 Notional Amount Fair Value Asset (1) Liability Derivatives not designated as hedging instruments Foreign currency forward contracts $ 368,448 $ 293 $ — Total $ 368,448 $ 293 $ — _________ (1) As presented in the consolidated balance sheet within other current assets. We did not have any derivative instruments as of December 31, 2019. The effect of foreign currency forward contracts not designated as hedging instruments in our consolidated statements of operations for the year ended December 31, 2020 was as follows (in thousand): Statement of Operations Classification Year Ended Derivatives not designated as hedging instruments Foreign currency forward contracts Other (expense) income, net $ 293 Total $ 293 There were no hedging activities for the years ended December 31, 2019 and 2018.

Inventory

Inventory	12 Months Ended
	Dec. 31, 2020
Inventory Disclosure [Abstract]
Inventory	Inventory Inventory as of December 31, 2020 consists of the following (in thousands): December 31, 2020 Raw materials $ 36,222 Work in progress 9,015 Finished goods 1,290 Total inventory $ 46,527

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Property and Equipment	Property and Equipment Property and equipment, net as of December 31, 2020 and 2019 consists of the following (in thousands): December 31, 2020 2019 Laboratory equipment $ 120,714 $ 108,257 Leasehold improvements 179,901 152,426 Furniture, fixtures and other 4,662 3,316 Computer equipment and software 13,398 11,985 Internally developed software 7,020 7,020 Right-of-use asset, financing 56,348 9,853 Construction in progress 34,507 3,222 416,550 296,079 Less: Accumulated depreciation (119,661) (94,584) Property and equipment, net $ 296,889 $ 201,495 Depreciation and amortization expense for the years ended December 31, 2020, 2019 and 2018 was $31.3 million, $31.0 million, $24.9 million, respectively.

Other Balance Sheet Components

Other Balance Sheet Components	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Other Balance Sheet Components	Balance Sheet Components Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets, as of December 31, 2020 and 2019 consists of the following (in thousands): December 31, 2020 2019 Down payments to manufacturing vendors $ 216,538 $ — Prepaid expenses 15,647 8,475 Tenant incentives receivables 10,242 4,093 Interest receivable on marketable securities 9,725 6,835 Prepaid expenses and other current assets $ 252,152 $ 19,403 Accrued Liabilities Accrued liabilities, as of December 31, 2020 and 2019 consists of the following (in thousands): December 31, 2020 2019 Clinical trials $ 97,249 $ 6,291 Compensation-related 95,247 27,428 Raw materials 78,085 — Manufacturing 53,412 5,872 Development operations 29,253 2,567 Property and equipment 17,576 4,029 Commercial 6,922 — Other external goods and services 91,847 21,465 Accrued liabilities $ 469,591 $ 67,652 Other Current Liabilities Other current liabilities, as of December 31, 2020 and 2019 consists of the following (in thousands): December 31, 2020 2019 Lease liabilities - financing $ 24,328 $ — Lease liabilities - operating 5,972 3,583 Other 3,365 1,480 Other current liabilities $ 33,665 $ 5,063 The following table summarizes the activities in deferred revenue during the year ended December 31, 2020 (in thousands): December 31, 2019 Additions Deductions December 31, 2020 Product sales $ — $ 3,881,303 $ (82,134) $ 3,799,169 Grant revenue 2,777 6,775 (4,291) 5,261 Collaboration revenue 199,528 121,882 (81,228) 240,182 Total deferred liabilities $ 202,305 $ 4,009,960 $ (167,653) $ 4,044,612

Leases

Leases	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Leases	Leases We have entered into various long-term non-cancelable lease arrangements for our facilities and equipment expiring at various times through 2032. Certain of these arrangements have free rent periods or escalating rent payment provisions, which we recognize lease cost under such arrangements on a straight-line basis over the life of the leases. We have two campuses in Massachusetts, our Cambridge facility and our Moderna Technology Center (MTC), located in Norwood. Operating Leases Cambridge facility We occupy a multi-floor building at Technology Square in Cambridge, Massachusetts with a mix of offices and research laboratory space totaling approximately 175,000 square feet. Our Cambridge facility leases have expiry ranges from 2020 to 2029. In August 2019, we entered into an amendment to our lease agreements to consolidate our Technology Square space in Cambridge, Massachusetts. This included entering into a forward-starting lease agreement starting in January 2020 to acquire approximately 50,000 square feet of additional space at 200 Technology Square. In addition, our current 200 Technology Square lease has been extended for two years to 2029. As part of the lease amendment, we completely exited our leased space of approximately 60,000 square feet at 500 Technology Square by May 2020. We record operating lease cost for each of our operating leases on a straight-line basis from lease commencement date through the end of the lease term. Operating lease cost is recorded in operating expenses in our consolidated statements of operations Finance Leases Moderna Technology Center North (MTC North) In February 2019, we entered into a new lease agreement for office and laboratory space of approximately 200,000 square feet, MTC North, located in Norwood, Massachusetts. The lease commenced in the second quarter of 2019 and had an initial expiration date of 2031. We have the option to extend the lease for up to four additional five-year terms. Contemporaneously, we entered into an agreement to sublease approximately 64 percent of the leased space to a third party. In May 2020, we entered into an amendment to the lease whereby we exercised an option available in the original lease to receive a tenant improvement allowance in the amount of $22.2 million to be paid back over the term of the lease with interest and extend the term of the lease to 2035. In May 2020, we also amended our MTC North sublease agreement. As the result of that amendment, effective June 1, 2020, we obtained an additional, approximately 28,000 square feet, or 12 percent of the leased space in MTC North and the remainder of the space in July 2020 when the sublease expired. The lease modifications to MTC North in the second quarter of 2020 resulted in a change in lease classification, from operating to finance. Moderna Technology Center manufacturing facility (MTC South) In August 2016, we entered into a lease agreement for approximately 200,000 square feet of office, laboratory, and light manufacturing space, MTC South, in Norwood, Massachusetts. The lease will expire in September 2032. We have the option to extend the term for two extension periods of ten years each at market-based rents. The base rent is subject to increases over the term of the lease. Embedded Leases We have entered into multiple contract manufacturing service agreements with third parties which contain embedded leases within the scope of ASC 842. As of December 31, 2020, we had lease liabilities of $24.3 million related to the embedded leases. Certain embedded leases dedicated to our COVID-19 vaccine program prior to the EUA from the FDA were deemed to have no alternative use. The related right-of-use assets of $62.3 million were charged to research and development expense for the year ended December 31, 2020. Operating and financing lease right-of-use assets and lease liabilities as of December 31, 2020 and 2019 were as follows (in thousands): December 31, 2020 2019 Assets: Right-of-use assets, operating, net (1) (2) $ 90,201 $ 86,414 Right-of-use assets, financing, net (3) (4) 55,045 9,544 Total $ 145,246 $ 95,958 Liabilities: Current: Operating lease liabilities (5) $ 5,972 $ 3,583 Financing lease liabilities (5) 24,328 — Total current lease liabilities 30,300 3,583 Non-current: Operating lease liabilities, non-current 97,421 93,675 Financing lease liabilities, non-current 109,874 38,689 Total non-current lease liabilities 207,295 132,364 Total $ 237,595 $ 135,947 _______ (1) These assets are real estate related assets, which include land, office and laboratory spaces. (2) Net of accumulated depreciation. (3) These assets are real estate assets related to the MTC North and MTC South leases. (4) Included in property and equipment in the consolidated balance sheets, net of accumulated depreciation. (5) Included in other current liabilities in the consolidated balance sheets. The components of the lease costs for the year ended December 31, 2020 and 2019 were as follows (in thousands): December 31, 2020 2019 Operating lease costs $ 16,939 $ 17,015 Financing lease costs: Amortization of right-of-use assets, financing leases 1,011 309 Interest expense for financing lease liabilities 9,891 6,557 Total financing lease costs $ 10,902 $ 6,866 Short term lease costs $ 13,322 $ — Variable lease costs $ 5,229 $ 4,399 Total rent expense for the year ended December 31, 2018 was $19.1 million. Supplemental cash flow information relating to our leases for the year ended December 31, 2020 and 2019 was as follows (in thousands): December 31, 2020 2019 Cash paid for amounts included in measurement of lease liabilities: Operating cash flows used in operating leases $ (15,089) $ (16,121) Operating cash flows used in financing leases (8,523) (5,585) Financing cash flows used in financing leases (7,519) — Operating lease non-cash items: Right-of-use assets reduced through lease modifications and reassessments 6,755 2,717 Right-of-use assets obtained in exchange for operating lease liabilities 17,107 34,014 Finance lease non-cash items: Right-of-use assets obtained through lease modifications and reassessments 46,495 — Charge to financing lease obligation 1,304 971 Weighted average remaining lease terms and discount rates as of December 31, 2020 were as follows: December 31, 2020 Remaining lease term: Operating leases 11 years Finance leases 25 years Discount rate: Operating leases 10.3 % Finance leases 13.1 % Future minimum lease payments under non-cancelable lease agreements as of December 31, 2020, were as follows (in thousands): Fiscal Year Operating Leases (1) Financing Leases (1) 2021 $ 15,492 $ 36,579 2022 15,913 11,848 2023 16,008 12,054 2024 16,168 12,279 2025 16,567 12,493 Thereafter 93,599 428,059 Total minimum lease payments 173,747 513,312 Less amounts representing interest or imputed interest (70,354) (379,110) (2) Present value of lease liabilities $ 103,393 $ 134,202 ______ (1) Include the optional extensions in the MTC North and MTC South lease terms which represent a total of $338.9 million un-discounted future lease payments.
Leases	Leases We have entered into various long-term non-cancelable lease arrangements for our facilities and equipment expiring at various times through 2032. Certain of these arrangements have free rent periods or escalating rent payment provisions, which we recognize lease cost under such arrangements on a straight-line basis over the life of the leases. We have two campuses in Massachusetts, our Cambridge facility and our Moderna Technology Center (MTC), located in Norwood. Operating Leases Cambridge facility We occupy a multi-floor building at Technology Square in Cambridge, Massachusetts with a mix of offices and research laboratory space totaling approximately 175,000 square feet. Our Cambridge facility leases have expiry ranges from 2020 to 2029. In August 2019, we entered into an amendment to our lease agreements to consolidate our Technology Square space in Cambridge, Massachusetts. This included entering into a forward-starting lease agreement starting in January 2020 to acquire approximately 50,000 square feet of additional space at 200 Technology Square. In addition, our current 200 Technology Square lease has been extended for two years to 2029. As part of the lease amendment, we completely exited our leased space of approximately 60,000 square feet at 500 Technology Square by May 2020. We record operating lease cost for each of our operating leases on a straight-line basis from lease commencement date through the end of the lease term. Operating lease cost is recorded in operating expenses in our consolidated statements of operations Finance Leases Moderna Technology Center North (MTC North) In February 2019, we entered into a new lease agreement for office and laboratory space of approximately 200,000 square feet, MTC North, located in Norwood, Massachusetts. The lease commenced in the second quarter of 2019 and had an initial expiration date of 2031. We have the option to extend the lease for up to four additional five-year terms. Contemporaneously, we entered into an agreement to sublease approximately 64 percent of the leased space to a third party. In May 2020, we entered into an amendment to the lease whereby we exercised an option available in the original lease to receive a tenant improvement allowance in the amount of $22.2 million to be paid back over the term of the lease with interest and extend the term of the lease to 2035. In May 2020, we also amended our MTC North sublease agreement. As the result of that amendment, effective June 1, 2020, we obtained an additional, approximately 28,000 square feet, or 12 percent of the leased space in MTC North and the remainder of the space in July 2020 when the sublease expired. The lease modifications to MTC North in the second quarter of 2020 resulted in a change in lease classification, from operating to finance. Moderna Technology Center manufacturing facility (MTC South) In August 2016, we entered into a lease agreement for approximately 200,000 square feet of office, laboratory, and light manufacturing space, MTC South, in Norwood, Massachusetts. The lease will expire in September 2032. We have the option to extend the term for two extension periods of ten years each at market-based rents. The base rent is subject to increases over the term of the lease. Embedded Leases We have entered into multiple contract manufacturing service agreements with third parties which contain embedded leases within the scope of ASC 842. As of December 31, 2020, we had lease liabilities of $24.3 million related to the embedded leases. Certain embedded leases dedicated to our COVID-19 vaccine program prior to the EUA from the FDA were deemed to have no alternative use. The related right-of-use assets of $62.3 million were charged to research and development expense for the year ended December 31, 2020. Operating and financing lease right-of-use assets and lease liabilities as of December 31, 2020 and 2019 were as follows (in thousands): December 31, 2020 2019 Assets: Right-of-use assets, operating, net (1) (2) $ 90,201 $ 86,414 Right-of-use assets, financing, net (3) (4) 55,045 9,544 Total $ 145,246 $ 95,958 Liabilities: Current: Operating lease liabilities (5) $ 5,972 $ 3,583 Financing lease liabilities (5) 24,328 — Total current lease liabilities 30,300 3,583 Non-current: Operating lease liabilities, non-current 97,421 93,675 Financing lease liabilities, non-current 109,874 38,689 Total non-current lease liabilities 207,295 132,364 Total $ 237,595 $ 135,947 _______ (1) These assets are real estate related assets, which include land, office and laboratory spaces. (2) Net of accumulated depreciation. (3) These assets are real estate assets related to the MTC North and MTC South leases. (4) Included in property and equipment in the consolidated balance sheets, net of accumulated depreciation. (5) Included in other current liabilities in the consolidated balance sheets. The components of the lease costs for the year ended December 31, 2020 and 2019 were as follows (in thousands): December 31, 2020 2019 Operating lease costs $ 16,939 $ 17,015 Financing lease costs: Amortization of right-of-use assets, financing leases 1,011 309 Interest expense for financing lease liabilities 9,891 6,557 Total financing lease costs $ 10,902 $ 6,866 Short term lease costs $ 13,322 $ — Variable lease costs $ 5,229 $ 4,399 Total rent expense for the year ended December 31, 2018 was $19.1 million. Supplemental cash flow information relating to our leases for the year ended December 31, 2020 and 2019 was as follows (in thousands): December 31, 2020 2019 Cash paid for amounts included in measurement of lease liabilities: Operating cash flows used in operating leases $ (15,089) $ (16,121) Operating cash flows used in financing leases (8,523) (5,585) Financing cash flows used in financing leases (7,519) — Operating lease non-cash items: Right-of-use assets reduced through lease modifications and reassessments 6,755 2,717 Right-of-use assets obtained in exchange for operating lease liabilities 17,107 34,014 Finance lease non-cash items: Right-of-use assets obtained through lease modifications and reassessments 46,495 — Charge to financing lease obligation 1,304 971 Weighted average remaining lease terms and discount rates as of December 31, 2020 were as follows: December 31, 2020 Remaining lease term: Operating leases 11 years Finance leases 25 years Discount rate: Operating leases 10.3 % Finance leases 13.1 % Future minimum lease payments under non-cancelable lease agreements as of December 31, 2020, were as follows (in thousands): Fiscal Year Operating Leases (1) Financing Leases (1) 2021 $ 15,492 $ 36,579 2022 15,913 11,848 2023 16,008 12,054 2024 16,168 12,279 2025 16,567 12,493 Thereafter 93,599 428,059 Total minimum lease payments 173,747 513,312 Less amounts representing interest or imputed interest (70,354) (379,110) (2) Present value of lease liabilities $ 103,393 $ 134,202 ______ (1) Include the optional extensions in the MTC North and MTC South lease terms which represent a total of $338.9 million un-discounted future lease payments.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Strategic Collaborations Under our strategic collaboration agreements, we are committed to perform certain research, development, and manufacturing activities. As part of our PCV Agreement and PCV/SAV Agreement with Merck, we are committed to perform certain research, development and manufacturing activities related to PCV products through an initial Phase 2 clinical trial up to a budgeted amount of $243.0 million as of December 31, 2020 and 2019 (Note 5). Legal Proceedings We are not currently a party to any material legal proceedings. Indemnification Obligations As permitted under Delaware law, we indemnify our officers, directors, and employees for certain events, occurrences while the officer, or director is, or was, serving at our request in such capacity. The term of the indemnification is for the officer’s or director’s lifetime. We have standard indemnification arrangements in our leases for laboratory and office space that require us to indemnify the landlord against any liability for injury, loss, accident, or damage from any claims, actions, proceedings, or costs resulting from certain acts, breaches, violations, or non-performance under our leases. We enter into indemnification provisions under our agreements with counterparties in the ordinary course of business, typically with business partners, contractors, clinical sites and customers. Under these provisions, we generally indemnify and hold harmless the indemnified party for losses suffered or incurred by the indemnified party as a result of our activities. These indemnification provisions generally survive termination of the underlying agreement. The maximum potential amount of future payments we could be required to make under these indemnification provisions is unlimited. Through December 31, 2020 and 2019, we had not experienced any losses related to these indemnification obligations, and no material claims were outstanding. We do not expect significant claims related to these indemnification obligations and, consequently, concluded that the fair value of these obligations is negligible, and no related reserves were established. Purchase Commitments and Purchase Orders In May 2020, we entered into a 10-year strategic collaboration agreement with Lonza Ltd. to enable larger scale manufacture for our COVID-19 vaccine and additional Moderna products in the future. This agreement was reflected in the Global Long Term Agreement entered into between Moderna and Lonza on September 4, 2020. Under the terms of the agreement, we established dedicated manufacturing suites at Lonza’s facilities in the United States and Switzerland for the manufacture of mRNA-1273 at both sites. Certain arrangements under this strategic collaboration agreement are within the scope of lease accounting (see Note 11). We enter into agreements in the normal course of business with vendors and contract manufacturing organizations (CMOs) for raw materials and manufacturing services and with vendors for preclinical research studies, clinical trials and other goods or services. As of December 31, 2020, we had $659.5 million of non-cancelable purchase commitments related to raw materials and manufacturing agreements, including the Lonza agreement, which are expected to be paid through 2021. As of December 31, 2020, we had $27.0 million of non-cancelable purchase commitments for clinical services and other goods and services which are expected to be paid through 2024. These amounts represent our minimum contractual obligations, including termination fees. In addition to purchase commitments, we have agreements with third parties for various services, including services related to clinical operations and support and contract manufacturing, for which we are not contractually able to terminate for convenience and avoid any and all future obligations to the vendors. Certain agreements provide for termination rights subject to termination fees or wind down costs. Under such agreements, we are contractually obligated to make certain payments to vendors, mainly, to reimburse them for their unrecoverable outlays incurred prior to cancellation. At December 31, 2020, we had cancelable open purchase orders of $896.9 million in total under such agreements for our significant clinical operations and support and contract manufacturing. These amounts represent only our estimate of those items for which we had a contractual commitment to pay at December 31, 2020, assuming we would not cancel these agreements. The actual amounts we pay in the future to the vendors under such agreements may differ from the purchase order amounts. Licenses to Patented Technology On June 26, 2017, we entered into sublicense agreements with Cellscript, LLC and its affiliate, mRNA RiboTherapeutics, Inc. to sublicense certain patent rights. Pursuant to each agreement, we are required to pay certain license fees, annual maintenance fees, minimum royalties on future net sales and milestone payments contingent on achievement of certain development, regulatory and commercial milestones for specified products, on a product-by-product basis. The development and regulatory milestone payments, up to $1.5 million for therapeutic and prophylactic products and up to $0.5 million for diagnostic products will be recognized as a cost of the asset acquired upon resolution of the associated contingency and will be capitalized or expensed depending on the nature of the associated asset as of the date of recognition. Conversely, commercial milestone payments, up to $24.0 million, and royalties based on annual net sales of licensed products for therapeutic and prophylactic products will be accounted for as additional expense of the related product sales in the period in which the corresponding sales occur. In connection with these sublicense agreements, we recognized sublicense grant fees of $22.0 million in 2018 and have no further obligation for additional sublicense grant fees. We recognized $6.9 million of royalties associated with our product sales in 2020.

Redeemable Convertible Preferre

Redeemable Convertible Preferred Stock and Common Stock	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Redeemable Convertible Preferred Stock and Common Stock	Redeemable Convertible Preferred Stock and Common Stock On February 28, 2018 and May 7, 2018, the Board of Directors approved an amendment to our Certificate of Incorporation resulting in a total of 775,000,000 shares of common stock and a total of 509,352,795 shares of redeemable convertible preferred stock being authorized, respectively. Upon completion of our IPO, our authorized capital stock consists of 1,600,000,000 shares of common stock, par value $0.0001 per share, and 162,000,000 shares of preferred stock, par value $0.0001 per share, all of which shares of preferred stock are undesignated. On December 11, 2018, we completed our IPO, whereby we sold 26,275,993 shares of common stock at a price of $23.00 per share. The aggregate net proceeds received by us from the IPO were $563.0 million, net of underwriting discounts and commissions of $33.2 million and offering expenses of $8.1 million payable by us. Upon the closing of the IPO, all of the outstanding shares of our redeemable convertible preferred stock were converted into 236,012,913 shares of the common stock. As of December 31, 2020 and 2019, we did not have any convertible preferred stock issued or outstanding. On February 14, 2020, we sold 26,315,790 shares of common stock at a price of $19.00 per share through a public equity offering. The aggregate net proceeds from the offering were $477.7 million, net of underwriting discounts, commissions and offering expenses. In addition, the underwriters exercised their options to purchase an additional 3,947,368 shares of common stock at the public offering price less underwriting discounts, resulting in additional net proceeds of $71.8 million. On May 21, 2020, we sold 17,600,000 shares of common stock at a price of $76.00 per share through a public equity offering. The aggregate net proceeds from the offering were $1.30 billion, net of underwriting discounts, commissions and offering expenses.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation Equity Plans In October 2013, we adopted the 2013 Equity Incentive Plan (the 2013 Incentive Plan) and the 2013 Unit Option and Grant Plan (the 2013 Option Plan), which provided for the grant of incentive units, non-qualified unit options, and restricted and unrestricted unit awards to our employees, officers, directors, advisors, and outside consultants. Historically, we also granted restricted stock to founders, officers, directors, and advisors outside any of the Plans. In August 2016, we adopted the 2016 Stock Option and Grant Plan (the 2016 Equity Plan), which replaced the 2013 Option Plan and the 2013 Incentive Plan. The 2016 Equity Plan and provided for the grant of incentive stock options, non-qualified stock options, restricted stock, unrestricted stock, and restricted stock units to our employees, officers, directors, consultants, and other key persons. In connection with the IPO, we adopted the 2018 Stock Option and Incentive Plan (the 2018 Equity Plan) in November 2018. The 2018 Equity Plan became effective on the date immediately prior to the effective date of the IPO and replaced our 2016 Plan. The 2018 Equity Plan provides flexibility to our compensation committee to use various equity-based incentive awards as compensation tools to motivate our workforce. We have initially reserved 13,000,000 shares of our common stock for the issuance of awards under the 2018 Equity Plan. The 2018 Equity Plan provides that the number of shares reserved and available for issuance under the plan will automatically increase each January 1, beginning on January 1, 2019, by 4% of the outstanding number of shares of our common stock on the immediately preceding December 31, or such lesser number of shares as determined by the Compensation and Talent Committee of our Board of Directors. The shares of common stock underlying any awards that are forfeited, canceled, held back upon exercise or settlement of an award to satisfy the exercise price or tax withholding, reacquired by us prior to vesting, satisfied without any issuance of stock, expire or are otherwise terminated (other than by exercise) under the 2018 Equity Plan and the 2016 Plan will be added back to the shares of common stock available for issuance under the 2018 Equity Plan. The terms and conditions of stock-based awards are defined at the sole discretion of our Board of Directors. We issue service-based awards, vesting over a defined period of service, and performance-based awards, vesting upon achievement of defined conditions. Service based awards generally vest over a four-year period, with the first 25% of such awards vesting following twelve months of continued employment or service. The remaining awards vests in twelve quarterly installments over the following twelve quarters. Stock options granted under the 2016 Equity Plan expire ten years from the date of grant and the exercise price must be at least equal to the fair market value of common stock on the grant date. As of December 31, 2020, we had a total of 64.2 million shares reserved for future issuance under our Equity Plans, of which 36.3 million shares were reserved for equity awards previously granted, and 27.9 million shares were available for future grants under the 2018 Equity Plan. No additional awards will be granted under the 2016 Equity Plan as it was replaced by the 2018 Equity Plan. Options We have granted options generally through the 2018 Equity Plan and 2016 Equity Plan. The following table summarizes our option activity as of December 31, 2020 and 2019: Number of Options Weighted Average Exercise Price per Share Weighted Average Grant Date Fair Value per Share Weighted- Average Remaining Contractual Term Aggregate Intrinsic Value (1) (in thousands) Outstanding at December 31, 2019 45,536,915 $ 13.82 $ 7.35 7.2 years $ 286,310 Granted 5,036,520 36.04 19.30 Exercised (13,888,434) 12.93 6.68 Canceled/forfeited (2,627,468) 18.14 10.56 Outstanding at December 31, 2020 34,057,533 17.14 9.12 6.7 years 2,976,235 Exercisable at December 31, 2020 17,461,374 10.99 5.67 5.4 years 1,632,365 Expected to vest at December 31, 2020 16,596,159 23.61 12.75 8.2 years 1,343,870 _______ (1) Aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the fair value of common stock for those options in the money as of December 31, 2020. The total intrinsic value of options exercised was $785.7 million, $75.6 million and $5.3 million for the years ended December 31, 2020, 2019 and 2018, respectively. The aggregate intrinsic value represents the difference between the exercise price and the selling price received by option holders upon the exercise of stock options during the period. The total consideration recorded as a result of stock option exercises was approximately $179.6 million for the year ended December 31, 2020. Restricted Common Stock Units We have granted restricted stock unit awards generally through the 2018 Equity Plan. The following table summarizes our restricted stock unit activity during the year ended December 31, 2020: Number of Units Weighted Average Grant Date Price per Unit Outstanding, non-vested at December 31, 2019 1,177,249 $ 19.01 Issued 1,478,093 37.37 Vested (247,349) 20.28 Canceled/forfeited (215,033) 23.64 Outstanding, non-vested at December 31, 2020 2,192,960 30.85 The total fair value of restricted stock units vested during the years ended December 31, 2020, 2019 and 2018, were $5.0 million, $5.5 million, and zero, respectively. 2018 Employee Stock Purchase Plan In November 2018, we adopted the 2018 Employee Stock Purchase Plan (the ESPP), which became effective on December 5, 2018. The ESPP initially reserves and authorizes the issuance of up to a total of 810,000 shares of common stock to participating employees. We will make one or more offerings, consisting of one or more purchase periods, each year to our employees to purchase shares under the ESPP. Offerings will usually begin every six months and will continue for six-month periods, referred to as offering periods. The purchase price at which shares are sold under the ESPP will be equal to 85% of the lower of the fair market value of the shares on the first business day of the offering period or the last business day of the purchase period. Employees are generally eligible to participate through payroll deductions of between 1% to 50% of their compensation and may not purchase more than 3,000 shares of common stock during each purchase period or $25,000 worth of shares of common stock in any calendar year. We began our first ESPP offering on June 1, 2019. There were 251,752 shares of common stock sold at a weighted average price of $27.97 per share under the ESPP during the year ended December 31, 2020. As of December 31, 2020, 3.6 million shares were available for future issuance under the ESPP. Valuation and Stock-Based Compensation Expense Stock-based compensation for options granted under our Equity Plans and share purchases under our ESPP is determined using the Black-Scholes option pricing model. The weighted-average assumptions used to estimate the fair value of options granted and ESPP for the years ended December 31, 2020, 2019 and 2018 are as follows: Weighted Average Years Ended December 31, 2020 2019 2018 Options: Risk-free interest rate 0.83 % 2.29 % 2.76 % Expected term 6.11 years 6.07 years 6.27 years Expected volatility 58 % 61 % 63 % Expected dividends — % — % — % Weighted average fair value per share $ 19.30 $ 11.35 $ 9.33 ESPP: Risk-free interest rate 0.14 % 1.95 % * Expected term 0.50 years 0.50 years * Expected volatility 54 % 53 % * Expected dividends — % — % * Weighted average fair value per share $ 32.18 $ 5.98 * _________ * - Not applicable Stock-Based Compensation Expense The following table presents the components and classification of stock-based compensation expense for the years ended December 31, 2020, 2019 and 2018 as follows (in thousands): Years Ended December 31, 2020 2019 2018 Options $ 77,748 $ 74,780 $ 63,288 Restricted common stock and units 12,401 5,125 9,277 Employee stock purchase plan 2,872 1,217 — Total $ 93,021 $ 81,122 $ 72,565 Research and development $ 56,155 $ 48,259 $ 37,659 Selling, general and administrative 36,866 32,863 34,906 Total $ 93,021 $ 81,122 $ 72,565 For the years ended December 31, 2020, 2019 and 2018, we recognized stock-based compensation expense of $9.6 million, $9.8 million and $10.6 million, respectively, related to performance-based awards, including awards with vesting or commencement contingent upon the IPO, for which achievement of such performance-based condition was deemed probable. Stock-based compensation expenses related to non-employee awards were immaterial for the years ended December 31, 2020, 2019 and 2018. As of December 31, 2020, there were $226.8 million of total unrecognized compensation cost related to non-vested stock-based compensation with respect to options and restricted stock granted. That cost is expected to be recognized over a weighted-average period of 2.9 years at December 31, 2020.

Employee Benefit Plan

Employee Benefit Plan	12 Months Ended
	Dec. 31, 2020
Retirement Benefits [Abstract]
Employee Benefit Plan	Employee Benefit PlanWe provide a retirement savings option to our eligible U.S. employees through the Moderna, Inc. 401(k) Plan (the 401(k) Plan), subject to certain limitations. As allowed under Section 401(k) of the Internal Revenue Code, the 401(k) Plan allows tax deferred salary deductions for eligible employees. We match 50% up to the first 6% contributed by a participant. All matching contributions are immediately vested. Total matching contributions to the 401(k) Plan were $5.0 million, $4.2 million, $2.1 million for the years ended December 31, 2020, 2019 and 2018, respectively.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Loss before provision for (benefit from) income taxes for the years ended December 31, 2020, 2019 and 2018 consist of the following (in thousands): Years Ended December 31, 2020 2019 2018 United States $ (745,445) $ (508,595) $ (380,473) Foreign 932 (6,121) (3,935) Loss before provision for (benefit from) income taxes $ (744,513) $ (514,716) $ (384,408) The provision for (benefit from) income taxes for the years ended December 31, 2020, 2019 and 2018 consist of the following components (in thousands): Years Ended December 31, 2020 2019 2018 Current: Federal $ — $ — $ (26) State 32 505 352 Foreign 2,519 — — Total current 2,551 505 326 Deferred: Federal — (1,200) — Total deferred — (1,200) — Total provision for (benefit from) income taxes $ 2,551 $ (695) $ 326 The reconciliation of the U.S. statutory income tax rate to our effective tax rate for the years ended December 31, 2020, 2019 and 2018 are as follows: Years Ended December 31, 2020 2019 2018 Tax effected at statutory rate 21.0 % 21.0 % 21.0 % State taxes, net of federal benefit 3.6 % 7.9 % 6.3 % Non-deductible items (0.8) % 1.6 % — % Change in valuation allowance (47.4) % (33.0) % (28.5) % Federal research and development credits 3.8 % 2.5 % 1.5 % Foreign tax rate differential 0.0 % (0.2) % (0.2) % Stock compensation windfall 19.8 % — % — % Other (0.3) % 0.2 % (0.2) % Effective tax rate (0.3) % 0.0 % (0.1) % The significant components of our deferred tax assets and tax liabilities as of December 31, 2020 and 2019 are as follows (in thousands): December 31, 2020 2019 Deferred tax assets: Net operating loss carry-forwards $ 587,211 $ 268,173 Stock-based compensation 33,089 43,978 Capitalized licenses, research and development and start-up costs 13,985 19,891 Tax credit carry-forwards 99,024 77,222 Accrued expenses 26,962 7,377 Deferred revenue 29,785 53,475 Operating lease liabilities 22,313 26,571 Lease financing obligation 23,718 10,570 Capitalized inventory 38,058 — Other — 11 Total gross deferred tax assets 874,145 507,268 Less: valuation allowance (823,468) (470,753) Total deferred tax assets, net of valuation allowance 50,677 36,515 Deferred tax liabilities: Financing right-of-use assets (11,539) (2,612) Operating right-of-use assets (20,349) (24,944) Fixed assets (18,276) (8,959) Other (513) — Total deferred tax liabilities (50,677) (36,515) Net deferred tax assets $ — $ — We have evaluated the positive and negative evidence bearing upon the realization of our deferred tax assets, including our history of significant losses in every year since our inception and in accordance with the applicable accounting standards, have fully reserved the net deferred tax asset. We concluded that realization of our net deferred tax assets is not more-likely-than-not to be realized as of December 31, 2020. The valuation allowance increased by $352.7 million in the year ended December 31, 2020, primarily due to the increase in net operating loss carry-forwards, research and development tax credits and capitalized inventory. On a periodic basis, we reassess the valuation allowance on our deferred income tax assets, weighing positive and negative evidence to assess the recoverability of the deferred tax assets. In 2020, we reassessed the valuation allowance and considered negative evidence, including our cumulative losses over the three years ended December 31, 2020, and positive evidence, including our recent EUA for our COVID-19 vaccine. After assessing both the negative and positive evidence, we concluded that we should maintain the valuation allowance on our net operating losses and our other deferred tax assets as of December 31, 2020. The release of the valuation allowance, as well as the exact timing and the amount of such release, continue to be subject to, among other things, our level of profitability, revenue growth, clinical program progression and expectations regarding future profitability. Our total deferred tax asset balance subject to the valuation allowance was approximately $874.1 million at December 31, 2020. We will continue to monitor the need for a full or partial valuation allowance each quarter in 2021 and future periods. At December 31, 2020, we had approximately $2.26 billion and $1.70 billion of federal and state net operating loss carry-forwards, respectively, of which $380.1 million of federal and $1.70 billion of state loss carry-forwards begin to expire in 2030. Additionally, $1.88 billion of federal net operating loss carry-forward will carry forward indefinitely. At December 31, 2020 we also had federal and state research and development credit carry-forwards of approximately $73.3 million and $26.1 million, which begin to expire in 2030 and 2032, respectively. At December 31, 2020, we also had federal orphan drug and state investment tax credit carry-forwards of approximately $2.0 million and $3.9 million which begin to expire in 2039 and 2021, respectively. In March 2020, the Coronavirus Aid, Relief and Economic Security Act (the CARES Act) was signed into law. The CARES Act includes provisions relating to several aspects of corporate income taxes. We do not currently expect the CARES Act to have a significant impact on our provision for income taxes; however, we will continue to monitor the provisions of the CARES Act in relation to its operations. Utilization of the net operating loss (NOL) and tax credit carry-forwards may be subject to a substantial annual limitation due to ownership change limitations that have occurred previously, or that could occur in the future, as provided by Section 382 of the Internal Revenue Code of 1986, as amended, or Section 382, as well as similar state provisions and other provisions of the Internal Revenue Code. Ownership changes may limit the amount of NOLs and tax credit carry-forwards that can be utilized annually to offset future taxable income and tax, respectively. In general, an ownership change, as defined by Section 382, results from transactions that increase the ownership of 5% shareholders in the stock of a corporation by more than 50% in the aggregate over a three-year period. We may experience ownership changes in the future as a result of subsequent shifts in our stock ownership, some of which may be outside our control. We file U.S. federal income tax returns and income tax returns in various state, local and foreign jurisdictions. All tax years since the date of our incorporation remain open to examination by the major taxing jurisdictions (state and federal) to which we are subject, as carry-forward attributes generated in years past may still be adjusted upon examination by the Internal Revenue Service (IRS) or other authorities if they have or will be used in a future period. We are not currently under examination by the IRS, or any other jurisdictions, for any tax year. We recognize, in our financial statements, the effect of a tax position when it is more likely than not, based on the technical merits, that the position will be sustained upon examination. A reconciliation of the beginning and ending amounts of unrecognized tax benefits during the years ended December 31, 2020 and 2019 are as follows (in thousands): Balance as of December 31, 2018 $ 141 Decrease due to prior positions — Increase due to current year tax position — Balance as of December 31, 2019 141 Decrease due to prior positions — Increase due to current year tax positions — Balance as of December 31, 2020 $ 141 Unrecognized tax benefits may change during the next twelve months for items that arise in the ordinary course of business. We do not anticipate a material change to our unrecognized tax benefits over the next twelve months that would have an adverse effect on our consolidated operating results. We recognize interest and penalties, if applicable, related to uncertain tax positions as a component of income tax expense.

Net Loss per Share

Net Loss per Share	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Net Loss per Share	Net Loss per Share Net Loss per Share Attributable to Common Stockholders Basic and diluted net loss per share attributable to common stockholders for the years ended December 31, 2020, 2019 and 2018 are calculated as follows (in thousands, except share and per share data): Years Ended December 31, 2020 2019 2018 Numerator: Net loss $ (747,064) $ (514,021) $ (384,734) Premium paid on repurchase of redeemable convertible preferred stock — — (4,127) Cumulative dividends on redeemable convertible preferred stock — — (12,996) Net loss attributable to common stockholders $ (747,064) $ (514,021) $ (401,857) Denominator: Weighted average common shares used in net loss per share attributable to common stockholders, basic and diluted 381,333,059 330,802,136 81,114,183 Net loss per share attributable to common stockholders, basic and diluted $ (1.96) $ (1.55) $ (4.95) The following common stock equivalents, presented based on amounts outstanding as of December 31, 2020, 2019 and 2018 were excluded from the calculation of diluted net loss per share attributable to common stockholders for the periods indicated because their inclusion would have been anti-dilutive: December 31, 2020 2019 2018 Stock options 34,057,533 45,536,915 50,821,132 Restricted common stock — — 198,597 Restricted common stock units 2,192,960 1,177,249 458,715 36,250,493 46,714,164 51,478,444

Geographic Information

Geographic Information	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Geographic Information	Grant Revenue In September 2020, we entered into an agreement with the Defense Advanced Research Projects Agency (DARPA) for an award of up to $56.4 million to fund development of a mobile manufacturing prototype leveraging our existing manufacturing technology that is capable of rapidly producing vaccines and therapeutics. As of December 31, 2020, the committed funding, net of revenue earned was $4.6 million, with an additional $51.4 million available if DARPA exercises additional contract options. In April 2020, we entered into an agreement with BARDA for an award of up to $483.3 million to accelerate development of mRNA-1273, our vaccine candidate against COVID-19. In July 2020, we amended our agreement with BARDA to provide for an additional commitment of up to $471.6 million to support late-stage clinical development of mRNA-1273, including the execution of a 30,000 participant Phase 3 study in the U.S. The amendment increased the maximum award from BARDA from $483.3 million to $954.9 million. Under the terms of the agreement, BARDA will fund the advancement of mRNA-1273 to FDA licensure. All contract options have been exercised. As of December 31, 2020, the remaining available funding net of revenue earned was $444.3 million. In September 2016, we received an award of up to $125.8 million from BARDA, to help fund our Zika vaccine program. Three of the four contract options have been exercised. As of December 31, 2020, the remaining available funding net of revenue earned was $70.8 million, with an additional $8.4 million available if the final contract option is exercised. In January 2016, we entered a global health project framework agreement with the Gates Foundation to advance mRNA-based development projects for various infectious diseases, including human immunodeficiency virus (HIV). As of December 31, 2020, the available funding net of revenue earned was $11.4 million, with up to an additional $80.0 million available if additional follow-on projects are approved. The following tables summarize grant revenue and deferred grant revenue for and as of the periods presented (in thousands): Years Ended 2020 2019 2018 BARDA $ 521,652 $ 7,608 $ 6,736 Other grant revenue 7,253 4,565 5,820 Total grant revenue $ 528,905 $ 12,173 $ 12,556 December 31, 2020 2019 Deferred grant revenue $ 5,261 $ 2,777 In December 2020, we began selling our COVID-19 vaccine to the U.S. Government and international government agencies. Under the supply agreements with these government agencies, we received or billed for upfront deposits for our future vaccine supply, which are initially recorded as deferred revenue. We recognize revenue based on the fixed price per dose when control of the product has transferred and customer acceptance has occurred, unless such acceptance provisions are deemed perfunctory. Product sales by customer geographic location was as follows (in thousands): Year Ended December 31, 2020 United States $ 193,630 Rest of world 6,242 Total $ 199,872 There were no product sales in 2019 and 2018. We had one commercial product, our COVID-19 vaccine, authorized for use as of December 31, 2020. Geographic Revenue We operate in one reporting segment that primarily focuses on the discovery, development and commercialization of mRNA medicines. Our chief executive officer manages our operations and evaluates our financial performance on a consolidated basis. Most of our principal operations, other than manufacturing, and our decision-making functions are located at our corporate headquarters in the United States. Total revenue by geographic area of our customers and collaboration partners was as follows (in thousands): Years Ended December 31, 2020 2019 2018 United States $ 764,529 $ 54,976 $ 89,075 Rest of world 38,866 5,233 45,993 Total $ 803,395 $ 60,209 $ 135,068 Our property and equipment, including financing right-of-use asset, were principally located within the United States as of December 31, 2020 and 2019.

Subsequent Event

Subsequent Event	12 Months Ended
	Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent Event	Subsequent Events Subsequent to December 31, 2020, we have entered into several supply agreements with customers to provide our COVID-19 vaccine, up to 125.1 million doses, and have received upfront deposits of $125.4 million , b ased on the initial confirmed volume, subject to modifications. On February 18, 2021, the European Commission advised us that we had successfully tendered for the provision of 150 million doses of our COVID-19 vaccine in 2021. This tender is subject to execution of the Purchase Agreement, which is expected shortly following an opt out period for individual Member States that expired on February 25, 2021. Subsequent to December 31, 2020, we have entered into additional binding purchase commitments with third-party contractual manufacturing organizations for our COVID-19 vaccine under existing agreements. We are currently committed to minimum non-cancelable purchase obligations of $314.8 million related to these agreements, which are expected to be paid through 2021.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Basis of Presentation	Our consolidated financial statements are prepared in accordance with U.S. generally accepted accounting principles (GAAP). Any reference in these notes to applicable guidance is meant to refer to the authoritative accounting principles generally accepted in the United States as found in the Accounting Standard Codification (ASC) and Accounting Standards Updates (ASU) of the Financial Accounting Standards Board (FASB).The consolidated financial statements include the Company and its subsidiaries.
Principles of Consolidation	All intercompany transactions and balances have been eliminated in consolidation.
Use of Estimates	We have made estimates and judgments affecting the amounts reported in our consolidated financial statements and the accompanying notes. On an ongoing basis, we evaluate our estimates, including critical accounting policies or estimates related to revenue recognition, research and development expenses, income tax provisions, stock-based compensation, leases, derivative financial instruments, inventory, and useful lives of long-lived assets. We base our estimates on historical experience and various relevant assumptions that we believe 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. The actual results that we experience may differ materially from our estimates. Significant estimates relied upon in preparing these financial statements include, among others, those related to fair value of equity awards, revenue recognition, research and development expenses, leases, fair value of financial instruments, useful lives of property and equipment, income taxes, and our valuation allowance on our deferred tax assets.
Segment Information	We have determined that our chief executive officer is the chief operating decision maker (CODM). The CODM reviews financial information presented on a consolidated basis. Resource allocation decisions are made by the CODM based on consolidated results. There are no segment managers who are held accountable by the CODM for operations, operating results, and planning for levels or components below the consolidated unit level. As such, we have concluded that we operate as one segment.
Revenue Recognition	On January 1, 2019, we adopted ASC 606 (Revenue from Contracts with Customers ) using the modified retrospective transition method applied to those contracts which were not completed as of January 1, 2019. We recognized the cumulative effect of the adoption as an adjustment to the opening balance of accumulated deficit in the current period consolidated balance sheet. Results for reporting periods beginning after January 1, 2019 are presented under ASC 606, while prior period amounts have not been adjusted and continue to be reported in accordance with our historic accounting (ASC 605). ASC 606 applies to all contracts with customers, except for contracts that are within the scope of other standards, such as leases, insurance, collaboration arrangements and financial instruments. To determine the appropriate amount of revenue to be recognized for arrangements that we determine are within the scope of ASC 606, we perform the following five steps (the five-step model): (i) identify the contract(s) with our customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when or as each performance obligation is satisfied. Our revenue is primarily generated through grants from government-sponsored and private organizations, product sales and collaboration arrangements. Grant Revenue We have contracts with Biomedical Advanced Research and Development Authority (BARDA), a division of the Office of the Assistant Secretary for Preparedness and Response (ASPR) within the U.S. Department of Health and Human Services (HHS); the U.S. government’s Defense Advanced Research Projects Agency (DARPA); the Bill & Melinda Gates Foundation (Gates Foundation) and other government-sponsored and private organizations for research and development related activities that provide for payments for reimbursed costs, which may include overhead and general and administrative costs as well as a related profit margin. We recognize revenue from these contracts as we perform services under these arrangements when the funding is committed. Associated expenses are recognized when incurred as research and development expense. Revenues and related expenses are presented gross in the consolidated statements of operations as we have determined we are the primary obligor under the arrangements relative to the research and development services we perform as lead technical expert. Collaboration Revenue We account for a contract with a customer that is within the scope of ASC 606 using the five-step model. We account for a contract with a customer that is within the scope of ASC 606 when all of the following criteria are met: (i) the arrangement has been approved by the parties and the parties are committed to perform their respective obligations; (ii) each party’s rights regarding the goods and/or services to be transferred can be identified; (iii) the payment terms for the goods and/or services to be transferred can be identified; (iv) the arrangement has commercial substance; and (v) collection of substantially all of the consideration to which we will be entitled in exchange for the goods and/or services that will be transferred to the customer is probable. We also determine the term of the contract based on the period in which we and our customer have present and enforceable rights and obligations for purposes of identifying the performance obligations and determining the transaction price. We evaluate contracts that contain multiple promises to determine which promises are distinct. Promises are considered to be distinct and therefore, accounted for as separate performance obligations, provided that: (i) the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer and (ii) the promise to transfer the good or service to the customer is separately identifiable from other promises in the contract. Individual goods or services (or bundles of goods and/or services) that meet both criteria for being distinct are accounted for as separate performance obligations. Promises that are not distinct at contract inception are combined and accounted for as a single performance obligation. Options to acquire additional goods and/or services are evaluated to determine if such option provides a material right to the customer that it would not have received without entering into the contract. If so, the option is accounted for as a separate performance obligation. If not, the option is considered a marketing offer which would be accounted for as a separate contract upon the customer’s election. The transaction price is generally comprised of an upfront payment due at contract inception and variable consideration in the form of payments for our services and materials and milestone payments due upon the achievement of specified events. Other payments the Company could be entitled to include tiered royalties earned when customers recognize net sales of licensed products. We measure the transaction price based on the amount of consideration to which we expect to be entitled in exchange for transferring the promised goods and/or services to the customer. We utilize either the expected value method or the most likely amount method to estimate the amount of variable consideration, depending on which method is expected to better predict the amount of consideration to which we will be entitled. Amounts of variable consideration are included in the transaction price to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. With respect to arrangements that include payments for a development or regulatory milestone payment, we evaluate whether the associated event is considered probable of achievement and estimate the amount to be included in the transaction price using the most likely amount method. Milestone payments that are not within our control or the licensee, such as those dependent upon receipt of regulatory approval, are not considered to be probable of achievement until the triggering event occurs. At the end of each reporting period, we re-evaluate the probability of achievement of each milestone and any related constraint, and if necessary, adjust our estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenue and net loss in the period of adjustment. For arrangements that include sales-based royalties, including milestone payments based upon the achievement of a certain level of product sales, wherein the license is deemed to be the sole or predominant item to which the payments relate, we recognize revenue upon the later of: (i) when the related sales occur or (ii) when the performance obligation to which some or all of the payment has been allocated has been satisfied (or partially satisfied). Consideration that would be received for optional goods and/or services is excluded from the transaction price at contract inception. We generally allocate the transaction price to each performance obligation based on a relative standalone selling price basis. We develop assumptions that require judgment to determine the standalone selling price for each performance obligation in consideration of applicable market conditions and relevant entity-specific factors, including factors that were contemplated in negotiating the agreement with the customer and estimated research and development costs. However, in certain instances, we allocate variable consideration entirely to one or more performance obligation if the terms of the variable consideration relate to the satisfaction of the respective performance obligation and the amount allocated is consistent with the amount we would expect to receive for the satisfaction of the respective performance obligation. We recognize revenue based on the amount of the transaction price that is allocated to each respective performance obligation when or as the performance obligation is satisfied by transferring a promised good or service to the customer. For performance obligations that are satisfied at a point in time, we recognize revenue when control of the goods and/or services is transferred to the customer. For performance obligations that are satisfied over time, we recognize revenue by measuring the progress toward complete satisfaction of the performance obligation using a single method of measuring progress which depicts the performance in transferring control of the associated goods and/or services to the customer. We generally use input methods to measure the progress toward the complete satisfaction of performance obligations satisfied over time. With respect to arrangements containing a license to our intellectual property that is determined to be distinct from the other performance obligations identified in the arrangement, we recognize revenue from amounts allocated to the license when the license is transferred to the licensee and the licensee is able to use and benefit from the license. For licenses that are bundled with other promises, we utilize judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. Significant management judgment is required in
Cash and Cash Equivalents	We consider all highly liquid investments with an original maturity of 90 days or less from the date of purchase to be cash equivalents.
Restricted Cash	Restricted cash is composed of amounts held on deposit related to our lease arrangements. The funds are maintained in money market accounts and are recorded at fair value. We classify our restricted cash as either current or non-current based on the terms of the underlying lease arrangement.
Investments	We invest our excess cash balances in marketable debt securities. We classify our investments in marketable debt securities as available-for-sale. We report available-for-sale investments at fair value at each balance sheet date, and include any unrealized holding gains and losses (the adjustment to fair value) in accumulated other comprehensive gain (loss), a component of stockholders’ equity. Realized gains and losses are determined using the specific-identification method, and are included in other (expense) income, net in our consolidated statements of operations. We classify our available-for-sale marketable securities as current or non-current based on each instrument’s underlying effective maturity date and for which we have the intent and ability to hold the investment for a period of greater than 12 months. Marketable securities with maturities of less than 12 months are classified as current and are included in investments in the consolidated balance sheets. Marketable securities with maturities greater than 12 months for which we have the intent and ability to hold the investment for greater than 12 months are classified as non-current and are included in investments, non-current in the consolidated balance sheets.We evaluate securities for impairment at the end of each reporting period. Impairment is evaluated considering numerous factors, and their relative significance varies depending on the situation. Factors considered include whether a decline in fair value below the amortized cost basis is due to credit-related factors or non-credit-related factors, the financial condition and near-term prospects of the issuer, and our intent and ability to hold the investment to allow for an anticipated recovery in fair value. A credit-related impairment is recognized as an allowance on the balance sheet with a corresponding adjustment to earnings. Any impairment that is not credit- related is recognized in other comprehensive (loss) income, net of applicable taxes.
Accounts Receivable and Allowance for Doubtful Accounts	We have accounts receivable amounts due from our product sales and related vaccine supply agreements and our grant agreements. We also have accounts receivable amounts due from strategic collaborators as a result of manufacturing and research and development services provided under collaboration arrangements, or milestones achieved, but not yet paid. Amounts payable to us are recorded as accounts receivable when our right to consideration is unconditional. To estimate the allowance for doubtful accounts, we make judgments about the creditworthiness of our customers based on ongoing credit evaluation and historical experience.
Concentrations of Credit Risk	Financial instruments that subject us to significant concentrations of credit risk consist primarily of cash, cash equivalents, restricted cash, marketable securities, and accounts receivable. Our investment portfolio comprises money market funds, marketable debt securities, including U.S. Treasury securities, debt securities of U.S. government agencies and corporate entities and commercial paper. Our cash management and investment policy limits investment instruments to investment-grade securities with the objective to preserve capital and to maintain liquidity until the funds can be used in business operations. Bank accounts in the United States are insured by the Federal Deposit Insurance Corporation (FDIC) up to $250,000. Our primary operating accounts significantly exceed the FDIC limits.
Significant Customers	Our accounts receivable are generally unsecured and are from customers in different countries. We generated revenue from grants made by government-sponsored and private organizations, product sales to the U.S. Government and international government agencies, and to a lesser extent, strategic alliances in 2020. Historically, we generated revenue primarily from strategic alliances.
Derivative Instruments and Hedging Activities	We record all derivatives on our consolidated balance sheets at fair value. The accounting for changes in the fair value of a derivative depends on whether the derivative has been designated and qualifies for hedge accounting. Hedge accounting generally provides for the matching of the timing of gain or loss recognition on the hedging instrument with the recognition of the changes in the fair value of the hedged asset or liability that are attributable to the hedged risk in a fair value hedge or the earnings effect of the hedged forecasted transactions in a cash flow hedge. We may enter into derivative contracts that are intended to economically hedge certain risk, even though hedge accounting does not apply or we elect not to apply hedge accounting. Foreign currency gains or losses associated with derivatives that are not designated as hedging instruments for accounting purposes are recorded within other (expense) income, net, in our consolidated statements of operations.
Fair Value Measurements	Fair value is defined as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities, which are required to be recorded at fair value, we consider the principal or most advantageous market in which we would transact and the market-based risk measurements or assumptions that market participants would use in pricing the asset or liability, such as risks inherent in valuation techniques, transfer restrictions and credit risk. FASB ASC Topic 820, Fair Value Measurement (ASC 820), establishes a fair value hierarchy for instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and our assumptions (unobservable inputs). Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from our independent sources. Unobservable inputs are inputs that reflect our assumptions about the inputs that market participants would use in pricing the asset or liability, and are developed based on the best information available in the circumstances. The following fair value hierarchy is used to classify assets and liabilities based on the observable inputs and unobservable inputs used to value the assets and liabilities: • Level 1: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities; • Level 2: Quoted prices for similar assets and liabilities in active markets, quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability; or • Level 3: Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity). To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Our cash equivalents and marketable securities are reported at fair value determined using Level 1 and Level 2 inputs (Note 6). The fair value of our foreign currency forward contracts is calculated using Level 2 inputs, which include currency spot rates, forward rates, interest rate curve and credit or non-performance risk (Note 7). We do not have any non-financial assets or liabilities that should be recognized or disclosed at fair value on a recurring basis at December 31, 2020, 2019 and 2018. As of December 31, 2020 and 2019, we maintain letters of credit of $12.1 million and $11.8 million, respectively, related to our lease arrangements, which are secured by money market accounts in accordance with certain of our lease agreements. The amounts are recorded at fair value using Level 1 inputs and included as restricted cash in our consolidated balance sheets.
Inventory	Inventory is recorded at the lower of cost or net realizable value, with cost determined on a first-in, first-out (FIFO) basis. We periodically review the composition of inventory in order to identify excess, obsolete, slow-moving or otherwise unsaleable items. If unsaleable items are observed and there are no alternate uses for the inventory, we will record a write-down to net realizable value in the period that the decline in value is first recognized through a charge to cost of sales. The determination of whether inventory costs will be realizable requires estimates by management. If actual market conditions are less favorable than projected by management, additional write-downs of inventory may be required. Prior to an initial regulatory approval for our investigational medicines, we expense costs relating to raw materials and production of inventory as research and development expense in our consolidated statements of operations, in the period incurred. When we believe regulatory approval and subsequent commercialization of our investigational medicines is probable, and we also expect future
Construction in Progress and Property and Equipment	Construction in progress includes direct costs related to the construction of various property and equipment, including leasehold improvements, and is stated at original cost. Construction in progress includes costs incurred under construction contracts including project management services, engineering services, design services and development, construction services and other construction-related fees and services. Such costs are not depreciated until the asset is completed and placed into service. Once the asset is placed into service, these capitalized costs will be allocated to certain property and equipment categories and will be depreciated over the estimated useful life of the underlying assets. Property and equipment are stated at cost, net of accumulated depreciation. Depreciation is calculated using the straight-line method over the estimated useful lives of the assets. The estimated useful lives of property and equipment are described below: Estimated Useful Life Laboratory equipment 5 years Leasehold improvements Lesser of estimated useful life of improvement or remaining life of related lease Computer equipment and software 3 years Internally developed software 3 years Furniture, fixtures and other 5 years Right of use asset, financing Lease term Expenditures for maintenance and repairs are charged to expense as incurred. Upon retirement or sale, the cost of the assets disposed of, and the related accumulated depreciation, are removed from the accounts, and any resulting gain or loss is recorded to other (expense) income, net.
Impairment of Long-Lived Assets	We evaluate our long-lived assets, which consist of property and equipment, to determine if facts and circumstances indicate that the carrying amount of assets may not be recoverable. If such facts and circumstances exist, we assess the recoverability of the long-lived assets by comparing the projected future undiscounted net cash flows associated with the related asset or group of assets over their remaining lives against their respective carrying amounts. If such review indicates that such cash flows are not expected to be sufficient to recover the recorded value of the assets, the assets are written down to their estimated fair values based on the expected discounted future cash flows attributable to the assets or based on appraisals.
Leases	We adopted ASC 842 ( Leases ) on January 1, 2019 on a modified retrospective basis under which we recognized and measured leases existing at, or entered into after, the beginning of the period of adoption. We elected the optional transition approach of not adjusting our comparative period financial statements for the impacts of adoption. Therefore, we recognized the effects of applying ASC 842 as a cumulative-effect adjustment to accumulated deficit as of January 1, 2019, the effective date of this standard. Leases are classified at their commencement date, which is defined as the date on which the lessor makes the underlying asset available for use by the lessee, as either operating or finance leases based on the economic substance of the agreement. We recognize lease right-of-use assets and related liabilities in our consolidated balance sheets for both operating and finance leases. Lease liabilities are measured at the lease commencement date as the present value of the future lease payments using the interest rate implicit in the
Cost of Sales	Cost of sales includes cost of raw materials, production, transportation, freight and indirect overhead costs associated with our product revenue during the period and third-party royalties on net sales of our product. Cost of sales also includes adjustments for excess and obsolete inventory to the extent management determines that the cost cannot be recovered based on estimates about future demand.
Research and Development Costs	Research and development costs are expensed as incurred. Research and development expenses consist of costs incurred in performing research and development activities, including salaries and benefits, facilities costs, overhead costs, prelaunch inventory costs, contract services, and other outside costs. The value of goods and services received from contract research organizations and contract manufacturing organizations in the reporting period are estimated based on the level of services performed, and progress in the period in cases when we have not received an invoice from the supplier. Equipment or facilities that are acquired or constructed for research and development activities and that have alternative future uses, in research and development projects or otherwise, should be capitalized and depreciated as tangible assets. However, the costs of equipment or facilities that are acquired or constructed and intangibles that are purchased from others for a particular research and development project and that have no alternative future uses and therefore no separate economic values are considered research and development costs and are expensed when incurred. Certain equipment and leased facilities purchased for our COVID-19 vaccine program prior to the EUA from the FDA were deemed to have no alternative use. The related acquisition costs of such equipment and lease facilities of $109.6 million were charged to research and development expense for the year ended December 31, 2020. We did not recognize such expense for the years ended December 31, 2019 or 2018.
Patent Costs	Costs to secure, defend and maintain patents are expensed as incurred, and are classified as selling, general and administrative expenses due to the uncertainty of future benefits.
Stock-Based Compensation	We issue stock-based awards to employees and non-employees, generally in the form of stock options and restricted stock units (RSUs). We account for our stock-based compensation awards in accordance with ASC 718, Compensation—Stock Compensation . Most of our stock-based awards have been made to employees. We measure compensation cost for equity awards at their grant-date fair value and recognize compensation expense over the requisite service period, which is generally the vesting period, on a straight-line basis. The grant date fair value of stock options is estimated using the Black-Scholes option pricing model, which requires management to make assumptions with respect to the fair value of our common stock on the grant date, including the expected term of the award, the expected volatility of our stock, calculated based on a period of time generally commensurate with the expected term of the award, risk-free interest rates and expected dividend yields of our stock. Historically, for periods prior to our IPO, the fair value of the shares of common stock and common units underlying our stock-based awards were determined on each grant date by our board of directors based on valuation estimates from management considering our most recently available independent third-party valuation of our common stock. Our board of directors also assessed and considered, with input from management, additional objective and subjective factors that we believed were relevant and which may have changed from the date of the most recent valuation through the grant date. The grant date fair value of RSUs is estimated based on the fair value of our underlying common stock. For performance-based stock awards, we recognize stock-based compensation expense over the requisite service period using the accelerated attribution method when achievement is probable. We classify stock-based compensation expense in our consolidated statement of operations in the same manner in which the award recipient’s salary and related costs are classified or in which the award recipient’s service payments are classified.
Income Taxes	We use an asset and liability approach to account for income taxes. We recognize deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the financial reporting and tax bases of assets and liabilities. These differences are measured using the enacted statutory tax rates that are expected to be in effect for the years in which differences are expected to reverse. Valuation allowances are provided when the expected realization of deferred tax assets does not meet a “more likely than not” criterion. We make estimates and judgments about our future taxable income that are based on assumptions that are consistent with our plans and estimates. Should the actual amounts differ from our estimates, the amount of our valuation allowance could be materially impacted. Changes in these estimates may result in significant increases or decreases to our tax provision in a period in which such estimates are changed, which in turn would affect net income or loss. We recognize tax benefits from uncertain tax positions if we believe the position is more likely than not to be sustained on examination by the taxing authorities based on the technical merits of the position. We make adjustments to these reserves when facts and circumstances change, such as the closing of a tax audit or the refinement of an estimate. The provision for income taxes includes the effects of any reserves for tax positions that are not more likely than not to be sustained, as well as the related net interest and penalties.
Net Loss per Share Attributable to Common Stockholders	We calculate basic net loss per share attributable to common stockholders by dividing net loss attributable to common stockholders by the weighted average number of common shares outstanding for the period, without consideration for common stock equivalents. Upon the closing of our IPO, all outstanding shares of our redeemable convertible preferred stock were converted into common stock. We calculate diluted net loss per share attributable to common stockholders by dividing net loss attributable to common stockholders by the weighted average number of common shares outstanding after giving consideration to the dilutive effect of restricted common stock and stock options that are outstanding during the period. We have generated a net loss in all periods presented, therefore the basic and diluted net loss per share attributable to common stockholders are the same as the inclusion of the potentially dilutive securities would be anti-dilutive.
Comprehensive Loss	Comprehensive loss includes net loss and other comprehensive income (loss) for the period. Other comprehensive income (loss) mainly consists of unrealized gains and losses on our investments. Total comprehensive income (loss) for all periods presented have been disclosed in the consolidated statements of comprehensive loss.
Recently Adopted Accounting Standards/Recently Issued Accounting Standards Not Yet Adopted	In June 2016, the FASB issued ASU No. 2016-13, Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments . This standard changes how companies account for credit losses for most financial assets and certain other instruments. For trade receivables, loans and held-to-maturity debt securities, companies will be required to recognize an allowance for credit losses rather than reducing the carrying value of the asset. The amendments in this standard should be applied on a modified retrospective basis to all periods presented. We adopted this standard in the first quarter of 2020. Based on the composition of our investment portfolio and investment policy, the adoption of this standard did not have a material impact on our consolidated financial statements and disclosures. In August 2018, the FASB issued ASU 2018-15, Intangibles—Goodwill and Other—Internal-Use Software (Topic 350): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract . This standard requires capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). We adopted this standard in the first quarter of 2020 using the prospective method. The adoption of this standard did not have a material impact on our consolidated financial statements and disclosures. In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes . This standard removes certain exceptions for investments, intra-period allocations and interim calculations, and adds guidance to reduce complexity in accounting for income taxes. We early adopted this standard in the second quarter of 2020. The adoption of this standard did not have a material impact on our consolidated financial statements and disclosures. Recently Issued Accounting Standards Not Yet Adopted From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies and adopted by us as of the specified effective date. Unless otherwise discussed, we believe that the impact of recently issued standards that are not yet effective will not have a material impact on our consolidated financial statements and disclosures.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Reconciliation of Cash and Cash Equivalents	The following table provides a reconciliation of cash, cash equivalents and restricted cash in the consolidated balance sheets that sum to the total of the same such amounts shown in the consolidated statements of cash flows (in thousands): December 31, 2020 2019 Cash and cash equivalents $ 2,623,850 $ 235,876 Restricted cash 1,032 1,032 Restricted cash, non-current 11,053 10,791 Total cash, cash equivalents and restricted cash shown in the consolidated $ 2,635,935 $ 247,699
Reconciliation of Restricted Cash	The following table provides a reconciliation of cash, cash equivalents and restricted cash in the consolidated balance sheets that sum to the total of the same such amounts shown in the consolidated statements of cash flows (in thousands): December 31, 2020 2019 Cash and cash equivalents $ 2,623,850 $ 235,876 Restricted cash 1,032 1,032 Restricted cash, non-current 11,053 10,791 Total cash, cash equivalents and restricted cash shown in the consolidated $ 2,635,935 $ 247,699
Entities that Accounted for More than 10% of Total Revenue and Accounts Receivable	A significant portion of our revenue to date has been generated from the following entities that accounted for more than 10% of total revenue and accounts receivable for the periods presented: Percentage of Revenue Years Ended December 31, Percentage of Accounts Receivable December 31, 2020 2019 2018 2020 2019 Merck * 61 % 49 % * 13 % BARDA 65 % 13 % * 22 % 54 % Vertex * 10 % * * 17 % AstraZeneca * * 34 % * * U.S. Government (excluding BARDA) 24 % * * * * European Commission * * * 28 % * United Kingdom Government * * * 11 % * South Korea Government * * * 24 % * ________ * - Represents an amount of less than 10%
Estimated Useful Lives of Property and Equipment	The estimated useful lives of property and equipment are described below: Estimated Useful Life Laboratory equipment 5 years Leasehold improvements Lesser of estimated useful life of improvement or remaining life of related lease Computer equipment and software 3 years Internally developed software 3 years Furniture, fixtures and other 5 years Right of use asset, financing Lease term Property and equipment, net as of December 31, 2020 and 2019 consists of the following (in thousands): December 31, 2020 2019 Laboratory equipment $ 120,714 $ 108,257 Leasehold improvements 179,901 152,426 Furniture, fixtures and other 4,662 3,316 Computer equipment and software 13,398 11,985 Internally developed software 7,020 7,020 Right-of-use asset, financing 56,348 9,853 Construction in progress 34,507 3,222 416,550 296,079 Less: Accumulated depreciation (119,661) (94,584) Property and equipment, net $ 296,889 $ 201,495
Components of Accumulated Other Comprehensive Loss	The components of accumulated other comprehensive gain (loss) for the years ended December 31, 2020 and 2019 are as follows (in thousands): Unrealized Gain on Available-for-Sale Debt Securities Accumulated other comprehensive loss, balance at December 31, 2018 $ (1,320) Other comprehensive income 3,124 Accumulated other comprehensive gain, balance at December 31, 2019 1,804 Other comprehensive income 1,200 Accumulated other comprehensive gain, balance at December 31, 2020 $ 3,004

Grant Revenue (Tables)

Grant Revenue (Tables)	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following tables summarize grant revenue and deferred grant revenue for and as of the periods presented (in thousands): Years Ended 2020 2019 2018 BARDA $ 521,652 $ 7,608 $ 6,736 Other grant revenue 7,253 4,565 5,820 Total grant revenue $ 528,905 $ 12,173 $ 12,556 December 31, 2020 2019 Deferred grant revenue $ 5,261 $ 2,777 The following table summarizes our total consolidated net revenue from our strategic collaborators for the periods presented (in thousands): Years Ended December 31, Collaboration Revenue by Strategic Collaborator: 2020 2019 2018 (1) Merck $ 26,076 $ 36,608 $ 66,082 AstraZeneca 32,624 5,233 45,993 Vertex 15,505 6,195 10,437 Other 413 — — Total collaboration revenue $ 74,618 $ 48,036 $ 122,512 ________ (1) Under ASC 605 The following table summarizes the revenue recognized for the periods presented (in thousands): Years Ended December 31, 2020 2019 2018 Combined AZ Agreements $ 18,371 $ 4,650 $ 45,393 The following table summarizes the revenue and contra-revenue recognized for the periods presented (in thousands): Years Ended December 31, 2020 2019 2018 Contra-revenue under the May 2019 Amendment $ (7,088) $ (5,265) $ — Collaboration revenue under the 2015 Merck Agreement 62 492 24,582 Total contra-revenue $ (7,026) $ (4,773) $ 24,582

Product Sales (Tables)

Product Sales (Tables)	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Revenue from External Customers by Geographic Areas	Product sales by customer geographic location was as follows (in thousands): Year Ended December 31, 2020 United States $ 193,630 Rest of world 6,242 Total $ 199,872 Total revenue by geographic area of our customers and collaboration partners was as follows (in thousands): Years Ended December 31, 2020 2019 2018 United States $ 764,529 $ 54,976 $ 89,075 Rest of world 38,866 5,233 45,993 Total $ 803,395 $ 60,209 $ 135,068

Collaboration Agreements (Table

Collaboration Agreements (Tables)	12 Months Ended
	Dec. 31, 2020
Research and Development [Abstract]
Disaggregation of Revenue	The following tables summarize grant revenue and deferred grant revenue for and as of the periods presented (in thousands): Years Ended 2020 2019 2018 BARDA $ 521,652 $ 7,608 $ 6,736 Other grant revenue 7,253 4,565 5,820 Total grant revenue $ 528,905 $ 12,173 $ 12,556 December 31, 2020 2019 Deferred grant revenue $ 5,261 $ 2,777 The following table summarizes our total consolidated net revenue from our strategic collaborators for the periods presented (in thousands): Years Ended December 31, Collaboration Revenue by Strategic Collaborator: 2020 2019 2018 (1) Merck $ 26,076 $ 36,608 $ 66,082 AstraZeneca 32,624 5,233 45,993 Vertex 15,505 6,195 10,437 Other 413 — — Total collaboration revenue $ 74,618 $ 48,036 $ 122,512 ________ (1) Under ASC 605 The following table summarizes the revenue recognized for the periods presented (in thousands): Years Ended December 31, 2020 2019 2018 Combined AZ Agreements $ 18,371 $ 4,650 $ 45,393 The following table summarizes the revenue and contra-revenue recognized for the periods presented (in thousands): Years Ended December 31, 2020 2019 2018 Contra-revenue under the May 2019 Amendment $ (7,088) $ (5,265) $ — Collaboration revenue under the 2015 Merck Agreement 62 492 24,582 Total contra-revenue $ (7,026) $ (4,773) $ 24,582
Changes in Balances of Receivables and Contract Liabilities	The following table presents changes in the balances of our receivables and contract liabilities related to our strategic collaboration agreements during the year ended December 31, 2020 (in thousands): December 31, 2019 Additions Deductions December 31, 2020 Contract Assets: Accounts receivable $ 1,972 $ 120,821 $ (117,249) $ 5,544 Contract Liabilities: Deferred revenue $ 199,528 $ 121,882 $ (81,228) $ 240,182 During the year ended December 31, 2020, we recognized the following revenue as a result of the change in the contract liability balances related to our collaboration agreements (in thousands): Revenue recognized in the period from: Year Ended Amounts included in contract liabilities at the beginning of the period (1) $ 72,863 Performance obligations satisfied (or partially satisfied) in previous reporting periods (2) 8,366 ______________ (1) We first allocate revenue to the individual contract liability balance outstanding at the beginning of the period until the revenue exceeds that balance. If additional consideration is received on those contracts in subsequent periods, we assume all revenue recognized in the reporting period first applies to the beginning contract liability. (2) Related to changes in estimated costs for our future performance obligations and estimated variable considerations. The following table summarizes the balances of deferred revenue at period end, which is classified as current or non-current in the consolidated balance sheets based on the period the services are expected to be performed or control of the supply is expected to be transferred (in thousands): December 31, 2020 2019 Combined AZ Agreements $ 57,192 $ 73,669 The following table summarizes the revenue recognized for the periods presented (in thousands): Years Ended December 31, 2020 2019 2018 2016 VEGF Exercise $ 14,253 $ 583 $ — The following table summarizes the balances of deferred revenue at period end, which is classified as current or non-current in the consolidated balance sheets based on the period the services are expected to be performed or control of the supply is expected to be transferred (in thousands): December 31, 2020 2019 2016 VEGF Exercise $ 29,335 $ 41,266 The following table summarizes the revenue recognized for the periods presented (in thousands): Years Ended December 31, 2020 2019 2018 PCV/SAV Agreement $ 33,103 $ 41,382 $ 41,498 The following table summarizes the balances of deferred revenue, which is classified as current or non-current in the condensed consolidated balance sheets based on the period the services are expected to be performed or control of the supply is expected to be transferred for the periods presented (in thousands): December 31 2020 2019 PCV/SAV Agreement $ 51,007 $ 83,799 The following table summarizes the revenue recognized for the periods presented (in thousands): Years Ended December 31, 2020 2019 2018 Vertex First Extended Research Term $ 13,452 $ — $ — Vertex Agreement/2019 Amendment 2,053 6,197 10,400 Total $ 15,505 $ 6,197 $ 10,400 The following table summarizes the balances of deferred revenue, classified as current and non-current in the condensed consolidated balance sheets based on the term of the research period for the periods presented (in thousands): December 31, 2020 2019 Vertex Agreement (1) $ 2,648 $ 793 ____________ (1) Balance as of December 31, 2019 represents deferred revenue related to the Vertex 2019 Amendment The following table summarizes the activities in deferred revenue during the year ended December 31, 2020 (in thousands): December 31, 2019 Additions Deductions December 31, 2020 Product sales $ — $ 3,881,303 $ (82,134) $ 3,799,169 Grant revenue 2,777 6,775 (4,291) 5,261 Collaboration revenue 199,528 121,882 (81,228) 240,182 Total deferred liabilities $ 202,305 $ 4,009,960 $ (167,653) $ 4,044,612
Summary of Composition of the Total Transaction	The following table summarizes the composition of the total transaction price for the periods presented (in thousands): Transaction Price December 31, Combined 2018 AZ Agreements: 2020 2019 Upfront payments $ 240,000 $ 240,000 Sublicense reimbursement 1,000 1,000 Toxicity milestone payment 60,000 60,000 Competition milestone payment 60,000 60,000 Estimated reimbursement for IL-12 manufacturing obligations 35,830 40,782 Total $ 396,830 $ 401,782 The following table summarizes the composition of the total transaction price for the periods presented (in thousands): Transaction Price December 31, 2016 VEGF Exercise: 2020 2019 Option exercise fee $ 10,000 $ 10,000 Milestone payment 30,000 30,000 Sublicense reimbursement 2,250 2,250 Estimated reimbursement for clinical supply 18,062 15,621 Total $ 60,312 $ 57,871 The following table summarizes the composition of the total transaction price for the periods presented (in thousands): Transaction Price December 31, 2015 Merck Agreement: 2020 2019 Upfront payments $ 60,000 $ 60,000 Development milestones 5,000 5,000 Reduction of reimbursements paid to Merck (12,353) (5,265) Total $ 52,647 $ 59,735 The following table summarizes the composition of the total transaction price for the periods presented (in thousands): Transaction Price December 31, PCV/SAV Agreement: 2020 2019 Upfront payment $ 200,000 $ 200,000 Premium associated with the contemporaneous sale of Series H redeemable convertible preferred stock 13,050 13,050 Reimbursement for clinical supply 310 — Total $ 213,360 $ 213,050 The following table summarizes the composition of the total transaction price for the First Extended Research Term at December 31, 2020 (in thousands): Transaction Price Vertex Agreement - First Extended Research Term: December 31, 2020 Upfront payment $ 4,000 Research and development 39,798 Total $ 43,798 The following table summarizes the composition of the total transaction price for the periods presented (in thousands): Transaction Price Chiesi Agreement: December 31, 2020 Upfront payment $ 25,000 Research and development 17,496 Total $ 42,496
Summary of Total Transaction Price to the Identified Performance Obligations	The following table summarizes the allocation of the total transaction price to the identified performance obligations under the arrangement, and the amount of the transaction price unsatisfied as of December 31, 2020 (in thousands): Transaction Price Combined 2018 AZ Agreements: December 31, 2020 Combined 2018 AZ Agreement performance obligation $ 293,223 Preclinical development service - IL-12 8,133 Preclinical development service - oncology development target 8,133 Development and commercialization license and manufacturing obligation 85,750 Material right to receive development and commercialization rights 1,591 Total $ 396,830 Remaining unsatisfied performance obligation $ 87,225 The following table summarizes the total transaction price allocated to the single performance obligation under the arrangement, and the amount of the transaction price unsatisfied as of December 31, 2020 (in thousands): Transaction Price December 31, 2020 2016 VEGF Exercise combined performance obligation 60,312 Remaining unsatisfied performance obligation 41,877 The following table summarizes the total transaction price allocated to the combined performance obligation under the arrangement, and the amount of the transaction price unsatisfied as of December 31, 2020 (in thousands): Transaction Price December 31, 2020 2015 Merck Agreement $ 52,647 Remaining unsatisfied performance obligation $ — The following tables summarize the allocation of the total transaction price to the identified performance obligations under the arrangement, and the amount of the transaction price unsatisfied as of December 31, 2020 (in thousands): Transaction Price PCV/SAV Agreement: December 31, 2020 PCV performance obligation $ 206,356 KRAS performance obligation 7,004 Total $ 213,360 Remaining unsatisfied performance obligation $ 51,007 The following table summarizes the total transaction price allocated to the single performance obligation under the arrangement, and the amount of the transaction price unsatisfied as of December 31, 2020 (in thousands): Transaction Price December 31, 2020 First Extended Research Term transaction price $ 43,798 Remaining unsatisfied performance obligation $ 30,346 The following table summarizes the allocation of the transaction price to the identified performance obligations under the arrangement, and the amount of the transaction price unsatisfied as of December 31, 2020 (in thousands): Transaction Price December 31, 2020 Chiesi Agreement transaction price $ 42,496 Remaining unsatisfied performance obligation $ 42,293

Financial Instruments and Fai_2

Financial Instruments and Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Summary of Cash and Available-for-Sale Securities by Significant Investment Category	The following tables summarize our cash and available-for-sale securities by significant investment category at December 31, 2020 and 2019 (in thousands): December 31, 2020 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Cash and Cash Equivalents Current Marketable Securities Non- Current Marketable Securities Cash and cash equivalents $ 2,623,849 $ 1 $ — $ 2,623,850 $ 2,623,850 $ — $ — Available-for-sale: Certificates of deposit 238,774 49 (4) 238,819 — 215,389 23,430 U.S. treasury securities 491,549 69 — 491,618 — 491,618 — Debt securities of U.S. government agencies and corporate entities 1,888,022 4,294 (147) 1,892,169 — 1,276,751 615,418 $ 5,242,194 $ 4,413 $ (151) $ 5,246,456 $ 2,623,850 $ 1,983,758 $ 638,848 December 31, 2019 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Cash and Cash Equivalents Current Marketable Securities Non- Current Marketable Securities Cash and cash equivalents $ 225,874 $ — $ — $ 225,874 $ 225,874 $ — $ — Available-for-sale: Certificates of deposit 82,028 79 (6) 82,101 10,002 69,197 2,902 U.S. treasury securities 117,891 260 (2) 118,149 — 110,186 7,963 Debt securities of U.S. government agencies and corporate entities 834,187 2,708 (32) 836,863 — 687,741 149,122 $ 1,259,980 $ 3,047 $ (40) $ 1,262,987 $ 235,876 $ 867,124 $ 159,987
Amortized Cost and Estimated Fair Value of Marketable Securities, by Contractual Maturity	The amortized cost and estimated fair value of marketable securities, by contractual maturity at December 31, 2020 and 2019 are as follows (in thousands): December 31, 2020 Amortized Cost Estimated Fair Value Due in one year or less $ 1,980,963 $ 1,983,758 Due after one year through five years 637,382 638,848 Total $ 2,618,345 $ 2,622,606 December 31, 2019 Amortized Cost Estimated Fair Value Due in one year or less $ 864,958 $ 867,124 Due after one year through five years 159,148 159,987 Total $ 1,024,106 $ 1,027,111
Schedule of Unrealized Loss on Investments	The following table summarizes the amount of gross unrealized losses and the estimated fair value for our available-for-sale securities in an unrealized loss position by length of time the securities have been in an unrealized loss position at December 31, 2020 and 2019 (in thousands): Less than 12 Months 12 Months or More Total Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value As of December 31, 2020: Certificates of deposit $ (4) $ 81,524 $ — $ — $ (4) $ 81,524 Debt securities of U.S. government agencies and corporate entities (148) 507,016 — — (148) 507,016 Total $ (152) $ 588,540 $ — $ — $ (152) $ 588,540 As of December 31, 2019: Certificates of deposit $ (6) $ 12,822 $ — $ — $ (6) $ 12,822 U.S. treasury securities (2) 9,979 — — (2) 9,979 Debt securities of U.S. government agencies and corporate entities (32) 62,360 — — (32) 62,360 Total $ (40) $ 85,161 $ — $ — $ (40) $ 85,161
Schedule of Financial Assets Measured at Fair Value on Recurring Basis	The following tables summarize our financial assets measured at fair value on a recurring basis as of December 31, 2020 and 2019 (in thousands): Fair Value at December 31, 2020 Fair Value Measurement Using Level 1 Level 2 Assets: Money market funds $ 620,947 $ 620,947 $ — Certificates of deposit 238,819 — 238,819 U.S. treasury securities 491,618 — 491,618 Debt securities of U.S. government agencies and corporate entities 1,892,169 — 1,892,169 Derivative instruments (Note 7) 293 — 293 Total $ 3,243,846 $ 620,947 $ 2,622,899 Fair Value at December 31, 2019 Fair Value Measurement Using Level 1 Level 2 Assets: Certificates of deposit $ 82,101 $ — $ 82,101 U.S. treasury securities 118,149 — 118,149 Debt securities of U.S. government agencies and corporate entities 836,863 — 836,863 Total $ 1,037,113 $ — $ 1,037,113

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule Of Foreign Currency Derivatives	Total gross notional amount and fair value for foreign currency derivatives that are not designated as hedging instruments are accounted for as follows (in thousands): December 31, 2020 Notional Amount Fair Value Asset (1) Liability Derivatives not designated as hedging instruments Foreign currency forward contracts $ 368,448 $ 293 $ — Total $ 368,448 $ 293 $ — _________ (1) As presented in the consolidated balance sheet within other current assets. The effect of foreign currency forward contracts not designated as hedging instruments in our consolidated statements of operations for the year ended December 31, 2020 was as follows (in thousand): Statement of Operations Classification Year Ended Derivatives not designated as hedging instruments Foreign currency forward contracts Other (expense) income, net $ 293 Total $ 293

Inventory (Tables)

Inventory (Tables)	12 Months Ended
	Dec. 31, 2020
Inventory Disclosure [Abstract]
Schedule of Inventory, Current	Inventory as of December 31, 2020 consists of the following (in thousands): December 31, 2020 Raw materials $ 36,222 Work in progress 9,015 Finished goods 1,290 Total inventory $ 46,527

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment, Net	The estimated useful lives of property and equipment are described below: Estimated Useful Life Laboratory equipment 5 years Leasehold improvements Lesser of estimated useful life of improvement or remaining life of related lease Computer equipment and software 3 years Internally developed software 3 years Furniture, fixtures and other 5 years Right of use asset, financing Lease term Property and equipment, net as of December 31, 2020 and 2019 consists of the following (in thousands): December 31, 2020 2019 Laboratory equipment $ 120,714 $ 108,257 Leasehold improvements 179,901 152,426 Furniture, fixtures and other 4,662 3,316 Computer equipment and software 13,398 11,985 Internally developed software 7,020 7,020 Right-of-use asset, financing 56,348 9,853 Construction in progress 34,507 3,222 416,550 296,079 Less: Accumulated depreciation (119,661) (94,584) Property and equipment, net $ 296,889 $ 201,495

Other Balance Sheet Components

Other Balance Sheet Components (Tables)	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets, as of December 31, 2020 and 2019 consists of the following (in thousands): December 31, 2020 2019 Down payments to manufacturing vendors $ 216,538 $ — Prepaid expenses 15,647 8,475 Tenant incentives receivables 10,242 4,093 Interest receivable on marketable securities 9,725 6,835 Prepaid expenses and other current assets $ 252,152 $ 19,403
Schedule of Accrued Liabilities	Accrued liabilities, as of December 31, 2020 and 2019 consists of the following (in thousands): December 31, 2020 2019 Clinical trials $ 97,249 $ 6,291 Compensation-related 95,247 27,428 Raw materials 78,085 — Manufacturing 53,412 5,872 Development operations 29,253 2,567 Property and equipment 17,576 4,029 Commercial 6,922 — Other external goods and services 91,847 21,465 Accrued liabilities $ 469,591 $ 67,652
Other Current Liabilities	Other current liabilities, as of December 31, 2020 and 2019 consists of the following (in thousands): December 31, 2020 2019 Lease liabilities - financing $ 24,328 $ — Lease liabilities - operating 5,972 3,583 Other 3,365 1,480 Other current liabilities $ 33,665 $ 5,063
Schedule of Deferred Revenue	The following table presents changes in the balances of our receivables and contract liabilities related to our strategic collaboration agreements during the year ended December 31, 2020 (in thousands): December 31, 2019 Additions Deductions December 31, 2020 Contract Assets: Accounts receivable $ 1,972 $ 120,821 $ (117,249) $ 5,544 Contract Liabilities: Deferred revenue $ 199,528 $ 121,882 $ (81,228) $ 240,182 During the year ended December 31, 2020, we recognized the following revenue as a result of the change in the contract liability balances related to our collaboration agreements (in thousands): Revenue recognized in the period from: Year Ended Amounts included in contract liabilities at the beginning of the period (1) $ 72,863 Performance obligations satisfied (or partially satisfied) in previous reporting periods (2) 8,366 ______________ (1) We first allocate revenue to the individual contract liability balance outstanding at the beginning of the period until the revenue exceeds that balance. If additional consideration is received on those contracts in subsequent periods, we assume all revenue recognized in the reporting period first applies to the beginning contract liability. (2) Related to changes in estimated costs for our future performance obligations and estimated variable considerations. The following table summarizes the balances of deferred revenue at period end, which is classified as current or non-current in the consolidated balance sheets based on the period the services are expected to be performed or control of the supply is expected to be transferred (in thousands): December 31, 2020 2019 Combined AZ Agreements $ 57,192 $ 73,669 The following table summarizes the revenue recognized for the periods presented (in thousands): Years Ended December 31, 2020 2019 2018 2016 VEGF Exercise $ 14,253 $ 583 $ — The following table summarizes the balances of deferred revenue at period end, which is classified as current or non-current in the consolidated balance sheets based on the period the services are expected to be performed or control of the supply is expected to be transferred (in thousands): December 31, 2020 2019 2016 VEGF Exercise $ 29,335 $ 41,266 The following table summarizes the revenue recognized for the periods presented (in thousands): Years Ended December 31, 2020 2019 2018 PCV/SAV Agreement $ 33,103 $ 41,382 $ 41,498 The following table summarizes the balances of deferred revenue, which is classified as current or non-current in the condensed consolidated balance sheets based on the period the services are expected to be performed or control of the supply is expected to be transferred for the periods presented (in thousands): December 31 2020 2019 PCV/SAV Agreement $ 51,007 $ 83,799 The following table summarizes the revenue recognized for the periods presented (in thousands): Years Ended December 31, 2020 2019 2018 Vertex First Extended Research Term $ 13,452 $ — $ — Vertex Agreement/2019 Amendment 2,053 6,197 10,400 Total $ 15,505 $ 6,197 $ 10,400 The following table summarizes the balances of deferred revenue, classified as current and non-current in the condensed consolidated balance sheets based on the term of the research period for the periods presented (in thousands): December 31, 2020 2019 Vertex Agreement (1) $ 2,648 $ 793 ____________ (1) Balance as of December 31, 2019 represents deferred revenue related to the Vertex 2019 Amendment The following table summarizes the activities in deferred revenue during the year ended December 31, 2020 (in thousands): December 31, 2019 Additions Deductions December 31, 2020 Product sales $ — $ 3,881,303 $ (82,134) $ 3,799,169 Grant revenue 2,777 6,775 (4,291) 5,261 Collaboration revenue 199,528 121,882 (81,228) 240,182 Total deferred liabilities $ 202,305 $ 4,009,960 $ (167,653) $ 4,044,612

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Assets and Lease Liabilities	Operating and financing lease right-of-use assets and lease liabilities as of December 31, 2020 and 2019 were as follows (in thousands): December 31, 2020 2019 Assets: Right-of-use assets, operating, net (1) (2) $ 90,201 $ 86,414 Right-of-use assets, financing, net (3) (4) 55,045 9,544 Total $ 145,246 $ 95,958 Liabilities: Current: Operating lease liabilities (5) $ 5,972 $ 3,583 Financing lease liabilities (5) 24,328 — Total current lease liabilities 30,300 3,583 Non-current: Operating lease liabilities, non-current 97,421 93,675 Financing lease liabilities, non-current 109,874 38,689 Total non-current lease liabilities 207,295 132,364 Total $ 237,595 $ 135,947 _______ (1) These assets are real estate related assets, which include land, office and laboratory spaces. (2) Net of accumulated depreciation. (3) These assets are real estate assets related to the MTC North and MTC South leases. (4) Included in property and equipment in the consolidated balance sheets, net of accumulated depreciation. (5) Included in other current liabilities in the consolidated balance sheets.
Lease, Cost	The components of the lease costs for the year ended December 31, 2020 and 2019 were as follows (in thousands): December 31, 2020 2019 Operating lease costs $ 16,939 $ 17,015 Financing lease costs: Amortization of right-of-use assets, financing leases 1,011 309 Interest expense for financing lease liabilities 9,891 6,557 Total financing lease costs $ 10,902 $ 6,866 Short term lease costs $ 13,322 $ — Variable lease costs $ 5,229 $ 4,399 Supplemental cash flow information relating to our leases for the year ended December 31, 2020 and 2019 was as follows (in thousands): December 31, 2020 2019 Cash paid for amounts included in measurement of lease liabilities: Operating cash flows used in operating leases $ (15,089) $ (16,121) Operating cash flows used in financing leases (8,523) (5,585) Financing cash flows used in financing leases (7,519) — Operating lease non-cash items: Right-of-use assets reduced through lease modifications and reassessments 6,755 2,717 Right-of-use assets obtained in exchange for operating lease liabilities 17,107 34,014 Finance lease non-cash items: Right-of-use assets obtained through lease modifications and reassessments 46,495 — Charge to financing lease obligation 1,304 971 Weighted average remaining lease terms and discount rates as of December 31, 2020 were as follows: December 31, 2020 Remaining lease term: Operating leases 11 years Finance leases 25 years Discount rate: Operating leases 10.3 % Finance leases 13.1 %
Finance Lease Maturity	Future minimum lease payments under non-cancelable lease agreements as of December 31, 2020, were as follows (in thousands): Fiscal Year Operating Leases (1) Financing Leases (1) 2021 $ 15,492 $ 36,579 2022 15,913 11,848 2023 16,008 12,054 2024 16,168 12,279 2025 16,567 12,493 Thereafter 93,599 428,059 Total minimum lease payments 173,747 513,312 Less amounts representing interest or imputed interest (70,354) (379,110) (2) Present value of lease liabilities $ 103,393 $ 134,202 ______ (1) Include the optional extensions in the MTC North and MTC South lease terms which represent a total of $338.9 million un-discounted future lease payments.
Operating Lease Maturity	Future minimum lease payments under non-cancelable lease agreements as of December 31, 2020, were as follows (in thousands): Fiscal Year Operating Leases (1) Financing Leases (1) 2021 $ 15,492 $ 36,579 2022 15,913 11,848 2023 16,008 12,054 2024 16,168 12,279 2025 16,567 12,493 Thereafter 93,599 428,059 Total minimum lease payments 173,747 513,312 Less amounts representing interest or imputed interest (70,354) (379,110) (2) Present value of lease liabilities $ 103,393 $ 134,202 ______ (1) Include the optional extensions in the MTC North and MTC South lease terms which represent a total of $338.9 million un-discounted future lease payments.

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Options Activity	The following table summarizes our option activity as of December 31, 2020 and 2019: Number of Options Weighted Average Exercise Price per Share Weighted Average Grant Date Fair Value per Share Weighted- Average Remaining Contractual Term Aggregate Intrinsic Value (1) (in thousands) Outstanding at December 31, 2019 45,536,915 $ 13.82 $ 7.35 7.2 years $ 286,310 Granted 5,036,520 36.04 19.30 Exercised (13,888,434) 12.93 6.68 Canceled/forfeited (2,627,468) 18.14 10.56 Outstanding at December 31, 2020 34,057,533 17.14 9.12 6.7 years 2,976,235 Exercisable at December 31, 2020 17,461,374 10.99 5.67 5.4 years 1,632,365 Expected to vest at December 31, 2020 16,596,159 23.61 12.75 8.2 years 1,343,870 _______ (1) Aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the fair value of common stock for those options in the money as of December 31, 2020.
Restricted Common Stock Units Activity	The following table summarizes our restricted stock unit activity during the year ended December 31, 2020: Number of Units Weighted Average Grant Date Price per Unit Outstanding, non-vested at December 31, 2019 1,177,249 $ 19.01 Issued 1,478,093 37.37 Vested (247,349) 20.28 Canceled/forfeited (215,033) 23.64 Outstanding, non-vested at December 31, 2020 2,192,960 30.85
Weighted-Average Assumptions Used to Estimate the Fair Value of Options Granted	The weighted-average assumptions used to estimate the fair value of options granted and ESPP for the years ended December 31, 2020, 2019 and 2018 are as follows: Weighted Average Years Ended December 31, 2020 2019 2018 Options: Risk-free interest rate 0.83 % 2.29 % 2.76 % Expected term 6.11 years 6.07 years 6.27 years Expected volatility 58 % 61 % 63 % Expected dividends — % — % — % Weighted average fair value per share $ 19.30 $ 11.35 $ 9.33 ESPP: Risk-free interest rate 0.14 % 1.95 % * Expected term 0.50 years 0.50 years * Expected volatility 54 % 53 % * Expected dividends — % — % * Weighted average fair value per share $ 32.18 $ 5.98 * _________
Stock-Based Compensation Expense	The following table presents the components and classification of stock-based compensation expense for the years ended December 31, 2020, 2019 and 2018 as follows (in thousands): Years Ended December 31, 2020 2019 2018 Options $ 77,748 $ 74,780 $ 63,288 Restricted common stock and units 12,401 5,125 9,277 Employee stock purchase plan 2,872 1,217 — Total $ 93,021 $ 81,122 $ 72,565 Research and development $ 56,155 $ 48,259 $ 37,659 Selling, general and administrative 36,866 32,863 34,906 Total $ 93,021 $ 81,122 $ 72,565

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Loss Before Provision For (Benefit From) Income Taxes	Loss before provision for (benefit from) income taxes for the years ended December 31, 2020, 2019 and 2018 consist of the following (in thousands): Years Ended December 31, 2020 2019 2018 United States $ (745,445) $ (508,595) $ (380,473) Foreign 932 (6,121) (3,935) Loss before provision for (benefit from) income taxes $ (744,513) $ (514,716) $ (384,408)
Provision For (Benefit From) Income Taxes	The provision for (benefit from) income taxes for the years ended December 31, 2020, 2019 and 2018 consist of the following components (in thousands): Years Ended December 31, 2020 2019 2018 Current: Federal $ — $ — $ (26) State 32 505 352 Foreign 2,519 — — Total current 2,551 505 326 Deferred: Federal — (1,200) — Total deferred — (1,200) — Total provision for (benefit from) income taxes $ 2,551 $ (695) $ 326
Reconciliation of U.S. Statutory Income Tax Rate to Effective Tax Rate	The reconciliation of the U.S. statutory income tax rate to our effective tax rate for the years ended December 31, 2020, 2019 and 2018 are as follows: Years Ended December 31, 2020 2019 2018 Tax effected at statutory rate 21.0 % 21.0 % 21.0 % State taxes, net of federal benefit 3.6 % 7.9 % 6.3 % Non-deductible items (0.8) % 1.6 % — % Change in valuation allowance (47.4) % (33.0) % (28.5) % Federal research and development credits 3.8 % 2.5 % 1.5 % Foreign tax rate differential 0.0 % (0.2) % (0.2) % Stock compensation windfall 19.8 % — % — % Other (0.3) % 0.2 % (0.2) % Effective tax rate (0.3) % 0.0 % (0.1) %
Significant Components of Deferred Tax Assets and Tax Liabilities	The significant components of our deferred tax assets and tax liabilities as of December 31, 2020 and 2019 are as follows (in thousands): December 31, 2020 2019 Deferred tax assets: Net operating loss carry-forwards $ 587,211 $ 268,173 Stock-based compensation 33,089 43,978 Capitalized licenses, research and development and start-up costs 13,985 19,891 Tax credit carry-forwards 99,024 77,222 Accrued expenses 26,962 7,377 Deferred revenue 29,785 53,475 Operating lease liabilities 22,313 26,571 Lease financing obligation 23,718 10,570 Capitalized inventory 38,058 — Other — 11 Total gross deferred tax assets 874,145 507,268 Less: valuation allowance (823,468) (470,753) Total deferred tax assets, net of valuation allowance 50,677 36,515 Deferred tax liabilities: Financing right-of-use assets (11,539) (2,612) Operating right-of-use assets (20,349) (24,944) Fixed assets (18,276) (8,959) Other (513) — Total deferred tax liabilities (50,677) (36,515) Net deferred tax assets $ — $ —
Reconciliation of the Beginning and Ending Amounts of Unrecognized Tax Benefits Roll Forward	A reconciliation of the beginning and ending amounts of unrecognized tax benefits during the years ended December 31, 2020 and 2019 are as follows (in thousands): Balance as of December 31, 2018 $ 141 Decrease due to prior positions — Increase due to current year tax position — Balance as of December 31, 2019 141 Decrease due to prior positions — Increase due to current year tax positions — Balance as of December 31, 2020 $ 141

Net Loss per Share (Tables)

Net Loss per Share (Tables)	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Basic and Diluted Net Loss per Share Attributable to Common Stockholders	Basic and diluted net loss per share attributable to common stockholders for the years ended December 31, 2020, 2019 and 2018 are calculated as follows (in thousands, except share and per share data): Years Ended December 31, 2020 2019 2018 Numerator: Net loss $ (747,064) $ (514,021) $ (384,734) Premium paid on repurchase of redeemable convertible preferred stock — — (4,127) Cumulative dividends on redeemable convertible preferred stock — — (12,996) Net loss attributable to common stockholders $ (747,064) $ (514,021) $ (401,857) Denominator: Weighted average common shares used in net loss per share attributable to common stockholders, basic and diluted 381,333,059 330,802,136 81,114,183 Net loss per share attributable to common stockholders, basic and diluted $ (1.96) $ (1.55) $ (4.95)
Common Stock Equivalents Excluded from Calculation of Diluted Net Loss Per Share	The following common stock equivalents, presented based on amounts outstanding as of December 31, 2020, 2019 and 2018 were excluded from the calculation of diluted net loss per share attributable to common stockholders for the periods indicated because their inclusion would have been anti-dilutive: December 31, 2020 2019 2018 Stock options 34,057,533 45,536,915 50,821,132 Restricted common stock — — 198,597 Restricted common stock units 2,192,960 1,177,249 458,715 36,250,493 46,714,164 51,478,444

Geographic Information (Tables)

Geographic Information (Tables)	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Revenue from External Customers by Geographic Areas	Product sales by customer geographic location was as follows (in thousands): Year Ended December 31, 2020 United States $ 193,630 Rest of world 6,242 Total $ 199,872 Total revenue by geographic area of our customers and collaboration partners was as follows (in thousands): Years Ended December 31, 2020 2019 2018 United States $ 764,529 $ 54,976 $ 89,075 Rest of world 38,866 5,233 45,993 Total $ 803,395 $ 60,209 $ 135,068

Organization and Description _2

Organization and Description of Business (Details) $ / shares in Units, $ in Thousands	May 21, 2020USD ($)$ / sharesshares	Feb. 14, 2020USD ($)$ / sharesshares	Dec. 31, 2020USD ($)program	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Operating losses			$ 747,064	$ 514,021	$ 384,734
Shares of common stock issued (in shares) | shares	17,600,000	30,263,158
Price per share (usd per share) | $ / shares	$ 76	$ 19
Aggregate net proceeds from the offering	$ 1,300,000	$ 549,500
Accumulated deficit			$ 2,243,518	$ 1,496,454
Development programs | program			21

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Accounting Policies Narrative (Details)	12 Months Ended
	Dec. 31, 2020USD ($)segment	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Accounting Policies [Abstract]
Number of operating segments | segment	1
Allowance for doubtful accounts	$ 0	$ 0
Bad debt expense	0	0	$ 0
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment expenses	1,600,000	0	0
Research and development	1,370,339,000	496,309,000	454,082,000
Equipment and Leased Facilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Research and development	$ 109,600,000	0	$ 0
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument term	12 months
Marketable securities maturity term	12 months
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities maturity term	12 months
Level 1 | Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Letters of credit	$ 12,100,000	$ 11,800,000

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Cash and cash equivalents	$ 2,623,850	$ 235,876
Restricted cash	1,032	1,032
Restricted cash, non-current	11,053	10,791
Total cash, cash equivalents and restricted cash shown in the consolidated statements of cash flows	$ 2,635,935	$ 247,699	$ 670,491	$ 147,608

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Significant Customers (Details) - Customer Concentration Risk	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue | Merck
Concentration Risk [Line Items]
Concentration risk, percentage		61.00%	49.00%
Revenue | BARDA
Concentration Risk [Line Items]
Concentration risk, percentage	65.00%	13.00%
Revenue | Vertex
Concentration Risk [Line Items]
Concentration risk, percentage		10.00%
Revenue | AstraZeneca
Concentration Risk [Line Items]
Concentration risk, percentage			34.00%
Revenue | U.S. Government (excluding BARDA)
Concentration Risk [Line Items]
Concentration risk, percentage	24.00%
Accounts Receivable | Merck
Concentration Risk [Line Items]
Concentration risk, percentage		13.00%
Accounts Receivable | BARDA
Concentration Risk [Line Items]
Concentration risk, percentage	22.00%	54.00%
Accounts Receivable | Vertex
Concentration Risk [Line Items]
Concentration risk, percentage		17.00%
Accounts Receivable | European Commission
Concentration Risk [Line Items]
Concentration risk, percentage	28.00%
Accounts Receivable | United Kingdom Government
Concentration Risk [Line Items]
Concentration risk, percentage	11.00%
Accounts Receivable | South Korea Government
Concentration Risk [Line Items]
Concentration risk, percentage	24.00%

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Property and Equipment and Software Capitalization (Details)	12 Months Ended
	Dec. 31, 2020
Laboratory equipment
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years
Computer equipment and software
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Internally developed software
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Furniture, fixtures and other
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years

Summary of Significant Accoun_8

Summary of Significant Accounting Policies - Components of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	$ 1,174,810	$ 1,530,241	$ (551,365)
Other comprehensive income	1,200	3,124	(163)
Balance at end of period	2,561,375	1,174,810	1,530,241
Unrealized Gain on Available-for-Sale Debt Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	1,804	(1,320)
Other comprehensive income	1,200	3,124
Balance at end of period	$ 3,004	$ 1,804	$ (1,320)

Grant Revenue (Details)

Grant Revenue (Details) $ in Thousands	1 Months Ended			12 Months Ended
	Sep. 30, 2020USD ($)	Apr. 30, 2020USD ($)	Sep. 30, 2016USD ($)contract_option	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Jul. 31, 2020USD ($)
Disaggregation of Revenue [Line Items]
Number of contract options | contract_option			3
Revenues				$ 803,395	$ 60,209	$ 135,068
Deferred revenue				4,044,612	202,305
Grant revenue
Disaggregation of Revenue [Line Items]
Revenues				528,905	12,173	12,556
Deferred revenue				5,261	2,777
BARDA
Disaggregation of Revenue [Line Items]
Award amount		$ 483,300	$ 125,800
Other Commitment							$ 471,600
Amount committed for funding				444,300
Number of contract options exercised | contract_option			4
BARDA | Minimum
Disaggregation of Revenue [Line Items]
Award amount				483,300
BARDA | Maximum
Disaggregation of Revenue [Line Items]
Award amount				954,900
BARDA | Contract options
Disaggregation of Revenue [Line Items]
Available funding				8,400
Amount committed for funding				70,800
BARDA | Grant revenue
Disaggregation of Revenue [Line Items]
Revenues				521,652	7,608	6,736
DARPA
Disaggregation of Revenue [Line Items]
Award amount	$ 56,400
DARPA | Contract options
Disaggregation of Revenue [Line Items]
Available funding				51,400
Amount committed for funding				4,600
The Bill & Melinda Gates Foundation | Initial project
Disaggregation of Revenue [Line Items]
Available funding				11,400
Deferred revenue				80,000
Other Grant Revenue | Grant revenue
Disaggregation of Revenue [Line Items]
Revenues				$ 7,253	$ 4,565	$ 5,820

Product Sales (Details)

Product Sales (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenues	$ 803,395	$ 60,209	$ 135,068
Deferred revenue	3,867,193	63,310
Product sales
Disaggregation of Revenue [Line Items]
Revenues	199,872	0	0
Customer deposits
Disaggregation of Revenue [Line Items]
Deferred revenue	3,800,000
United States
Disaggregation of Revenue [Line Items]
Revenues	764,529	54,976	89,075
United States | Product sales
Disaggregation of Revenue [Line Items]
Revenues	193,630
Rest of world
Disaggregation of Revenue [Line Items]
Revenues	38,866	$ 5,233	$ 45,993
Rest of world | Product sales
Disaggregation of Revenue [Line Items]
Revenues	$ 6,242

Collaboration Agreements - Summ

Collaboration Agreements - Summary of Total Consolidated Net Revenues from Strategic Collaborators (Details) - Collaboration Revenue by Strategic Collaborator - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total collaboration revenue	$ 74,618	$ 48,036
Balance without adoption of ASC 605
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total collaboration revenue			$ 122,512
Merck
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total collaboration revenue	26,076	36,608
Merck | Balance without adoption of ASC 605
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total collaboration revenue			66,082
AstraZeneca
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total collaboration revenue	32,624	5,233
AstraZeneca | Balance without adoption of ASC 605
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total collaboration revenue			45,993
Vertex
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total collaboration revenue	15,505	6,195
Vertex | Balance without adoption of ASC 605
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total collaboration revenue			10,437
Other
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total collaboration revenue	$ 413	$ 0
Other | Balance without adoption of ASC 605
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total collaboration revenue			$ 0

Collaboration Agreements - Chan

Collaboration Agreements - Changes in Balances of Receivables and Contract Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020
Contract Liabilities:
Beginning balance	$ 202,305
Ending balance	4,044,612
Remaining performance obligations	87,225
Collaboration Revenue by Strategic Collaborator
Contract Assets:
Beginning balance	1,972
Additions	120,821
Deductions	(117,249)
Ending balance	5,544
Contract Liabilities:
Beginning balance	199,528
Additions	121,882
Deductions	(81,228)
Ending balance	240,182
Amounts included in contract liabilities at the beginning of the period	72,863
Performance obligations satisfied (or partially satisfied) in previous reporting periods	8,366
Remaining performance obligations	$ 327,700

Collaboration Revenue - Remaini

Collaboration Revenue - Remaining Performance Obligation (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 87,225
Collaboration Revenue by Strategic Collaborator
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	327,700
Combined 2018 AZ Agreements
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	396,830	$ 401,782
Combined 2018 AZ Agreements | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 77,500
Performance period	8 years 3 months
Combined 2018 AZ Agreements | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 9,700
Performance period
VEGF Exercise 2016
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 60,312	57,871
VEGF Exercise 2016 | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 41,877
Performance period	4 years 3 months
PCVSAV Agreement
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 213,360	213,050
PCVSAV Agreement | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 51,007
Performance period	3 years 3 months
Vertex Agreement
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations		$ 24,400
Vertex Agreement | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance period	1 year

Collaboration Agreements - Astr

Collaboration Agreements - AstraZeneca - Strategic Alliances in Cardiovascular and Oncology (Details)	1 Months Ended			12 Months Ended
	Jun. 30, 2018	Jan. 31, 2016	Mar. 31, 2013USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2016USD ($)	Jun. 30, 2019option	Mar. 31, 2014USD ($)optionmilestone
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Increase to the transaction price				$ (7,100,000)
Additions				4,009,960,000
Combined 2018 AZ Agreements
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Increase to the transaction price				5,000,000
2013 AZ Agreements
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Number of options to develop candidates | option								40
Estimated arrangement consideration								$ 180,000,000
Number of milestones | milestone								3
Option exercise fee			$ 10,000,000
Termination period			90 days
Additions			$ 240,000,000			$ 10,000,000
2013 AZ Agreements | VEGF-A product (AZD8601)
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Additions					$ 30,000,000
2013 AZ Agreements | Maximum
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Earn-out payments			12.00%
2013 AZ Agreements | Development Milestones
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Estimated arrangement consideration								$ 100,000,000
2013 AZ Agreements | Regulatory Milestones
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Estimated arrangement consideration								100,000,000
2013 AZ Agreements | Commercial Milestones
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Estimated arrangement consideration								$ 200,000,000
VEGF Exercise 2016
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Increase to the transaction price				400,000
2016 AZ Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Termination period		90 days
Suspension period		12 months
2016 AZ Agreement | Minimum
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Tiered royalties		10.00%
2016 AZ Agreement | Maximum
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Tiered royalties at default rate		20.00%
Tiered royalties		30.00%
2018 A&R Agreements
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Number of options to develop candidates | option							40
Termination period	90 days
Estimated reimbursement for clinical supply | VEGF Exercise 2016
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Increase to the transaction price				$ 2,400,000

Collaboration Agreements - Comp

Collaboration Agreements - Composition of the Total Transaction Price (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations	$ 87,225
Combined 2018 AZ Agreements
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations	396,830	$ 401,782
Combined 2018 AZ Agreements | Upfront payment
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations	240,000	240,000
Combined 2018 AZ Agreements | Sublicense reimbursement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations	1,000	1,000
Combined 2018 AZ Agreements | Milestone payment | Toxicity milestone payment
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations	60,000	60,000
Combined 2018 AZ Agreements | Milestone payment | Competition milestone payment
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations	60,000	60,000
Combined 2018 AZ Agreements | Estimated Reimbursement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations	$ 35,830	$ 40,782

Collaboration Agreements - Tota

Collaboration Agreements - Total Transaction Price to the Identified Performance Obligations (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 87,225
Combined 2018 AZ Agreements
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	396,830	$ 401,782
Combined 2018 AZ Agreement performance obligation | Combined 2018 AZ Agreements
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	293,223
Preclinical development service - IL-12 | Combined 2018 AZ Agreements
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	8,133
Preclinical development service - oncology development target | Combined 2018 AZ Agreements
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	8,133
Development and commercialization license and manufacturing obligation | Combined 2018 AZ Agreements
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	85,750
Material right to receive development and commercialization rights | Combined 2018 AZ Agreements
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 1,591

Collaboration Agreements - Reve

Collaboration Agreements - Revenue Recognized (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Increase to the transaction price	$ (7,100)
Combined 2018 AZ Agreements
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Increase to the transaction price	5,000
Collaboration revenue | Combined 2018 AZ Agreements
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total collaboration revenue	18,371	$ 4,650	$ 45,393
Increase to the transaction price	$ 12,500

Collaboration Agreements - Defe

Collaboration Agreements - Deferred Revenue which is Classified as Current or Non-Current in the Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Contract with customer, liability	$ 4,044,612	$ 202,305
Combined 2018 AZ Agreements
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Contract with customer, liability	$ 57,192	$ 73,669

Collaboration Agreements - VEGF

Collaboration Agreements - VEGF Total Transaction Price (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations	$ 87,225
VEGF Exercise 2016
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations	60,312	$ 57,871
Option exercise fee | VEGF Exercise 2016
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations	10,000	10,000
Milestone payment | VEGF Exercise 2016
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations	30,000	30,000
Sublicense reimbursement | VEGF Exercise 2016
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations	2,250	2,250
Estimated reimbursement for clinical supply | VEGF Exercise 2016
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations	$ 18,062	$ 15,621

Collaboration Agreements - To_2

Collaboration Agreements - Total Transaction Price Allocated to the Single Identified Performance Obligation (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 87,225
VEGF Exercise 2016
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	60,312	$ 57,871
VEGF Exercise 2016 | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 41,877

Collaboration Agreements - VE_2

Collaboration Agreements - VEGF Revenue Recognized (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
VEGF Exercise 2016
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total collaboration revenue	$ 14,253	$ 583	$ 0

Collaboration Agreements - VE_3

Collaboration Agreements - VEGF Deferred Revenue which is Classified as Current or Non-Current in the Balance Sheets (Details) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Contract with Customer, Liability	$ 4,044,612	$ 202,305
VEGF Exercise 2016
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Contract with Customer, Liability	$ 29,335	$ 41,266

Collaboration Agreements - Merc

Collaboration Agreements - Merck – Strategic Alliances in Infectious Diseases and Cancer Vaccines (Details) - USD ($) $ in Thousands	May 21, 2020	Feb. 14, 2020	Apr. 30, 2018	Jun. 30, 2016	Jan. 31, 2016	Jan. 31, 2015	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	May 31, 2019	Jan. 01, 2019	Jun. 30, 2017
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Deferred revenue								$ 3,842,307	$ (44,119)	$ (65,260)
Remaining performance obligations							$ 87,225	87,225
Increase to the transaction price								(7,100)
Aggregate net proceeds from the offering	$ 1,300,000	$ 549,500
Deferred revenue							4,044,612	4,044,612	202,305
Additions								4,009,960
Collaboration revenue
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Deferred revenue							240,182	240,182	199,528
Additions								121,882
Merck agreement 2015
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Deferred revenue											$ 50,000
Proceeds from equity investment						$ 50,000
Initial research period											4 years
Remaining performance obligations							52,647	52,647	59,735			$ 65,000
Performance period											3 years
Increase to the transaction price								12,353	5,265
Additions					$ 10,000
Merck agreement 2015 | Collaboration revenue
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue from contract with customer, excluding assessed tax								62	492	24,582
Separate agreements with Merck | Collaboration revenue
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue from contract with customer, excluding assessed tax								(7,026)	(4,773)	24,582
PCV Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Estimated arrangement consideration													$ 250,000
Additions				$ 200,000
PCV Agreement | Series H Redeemable Convertible Preferred Stock
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Aggregate net proceeds from the offering			$ 125,000
Premium recorded to deferred revenue			13,000
PCV Agreement | PCV products
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Estimated arrangement consideration			$ 243,000				243,000	243,000	243,000
PCVSAV Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations							213,360	213,360	213,050
Deferred revenue							51,007	51,007	83,799
PCVSAV Agreement | Collaboration revenue
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue from contract with customer, excluding assessed tax								33,103	41,382	$ 41,498
Increase to the transaction price							3,500	3,500
Upfront payment | Merck agreement 2015
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations							60,000	60,000	60,000			60,000
Upfront payment | PCVSAV Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations							200,000	200,000	200,000
Milestone payment | Merck agreement 2015
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue from contract with customer, excluding assessed tax											$ 5,000
Remaining performance obligations												$ 5,000
Premium associated with the contemporaneous sale of Series H redeemable convertible preferred stock | PCVSAV Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations							13,050	13,050	13,050
Upfront Payment, Research And Development | Merck agreement 2015
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations							5,000	5,000	$ 5,000
PCV Performance Obligation | PCVSAV Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations							206,356	206,356
KRAS Performance Obligation | PCVSAV Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations							$ 7,004	$ 7,004

Collaboration Agreements - ME_2

Collaboration Agreements - MERCK Composition of the Total Transaction Price (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2019
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations	$ 87,225
Decrease to the transaction price	7,100
Merck agreement 2015
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations	52,647	$ 59,735	$ 65,000
Decrease to the transaction price	(12,353)	(5,265)
Merck agreement 2015 | Upfront payment
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations	60,000	60,000	$ 60,000
Merck agreement 2015 | Upfront Payment, Research And Development
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations	$ 5,000	$ 5,000

Collaboration Agreements - ME_3

Collaboration Agreements - MERCK Total Transaction Price to the Identified Performance Obligations (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2019
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 87,225
Merck agreement 2015
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	52,647	$ 59,735	$ 65,000
Merck agreement 2015 | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 0

Collaboration Agreements - ME_4

Collaboration Agreements - MERCK Revenue and Contra-Revenue Recognized (Details) - Collaboration revenue - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Contra-revenue under the May 2019 Amendment
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total collaboration revenue	$ (7,088)	$ (5,265)	$ 0
Collaboration revenue under the 2015 Merck Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total collaboration revenue	62	492	24,582
Separate agreements with Merck
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total collaboration revenue	$ (7,026)	$ (4,773)	$ 24,582

Collaboration Agreements - PCV_

Collaboration Agreements - PCV/SAV Composition of the Total Transaction Price (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 87,225
PCVSAV Agreement
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	213,360	$ 213,050
PCVSAV Agreement | Upfront payment
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	200,000	200,000
PCVSAV Agreement | Premium associated with the contemporaneous sale of Series H redeemable convertible preferred stock
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	13,050	13,050
PCVSAV Agreement | Reimbursement for clinical supply
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 310	$ 0

Collaboration Agreements - PC_2

Collaboration Agreements - PCV/SAV Total Transaction Price to the Identified Performance Obligations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 87,225
Increase to the transaction price	(7,100)
PCVSAV Agreement
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	213,360	$ 213,050
PCVSAV Agreement | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	51,007
PCVSAV Agreement | PCV Performance Obligation
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	206,356
PCVSAV Agreement | KRAS Performance Obligation
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	7,004
PCVSAV Agreement | Reimbursement for clinical supply
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	310	$ 0
Increase to the transaction price	$ 300

Collaboration Agreements - PC_3

Collaboration Agreements - PCV/SAV Revenue Recognized (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Collaboration revenue | PCVSAV Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total collaboration revenue	$ 33,103	$ 41,382	$ 41,498

Collaboration Agreements - PC_4

Collaboration Agreements - PCV/SAV Balances of Deferred Revenue (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Contract with customer, liability	$ 4,044,612	$ 202,305
PCVSAV Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Contract with customer, liability	$ 51,007	$ 83,799

Collaboration Agreements - Vert

Collaboration Agreements - Vertex – 2016 Strategic Alliance in Cystic Fibrosis (Details)	1 Months Ended		12 Months Ended
	Jul. 31, 2019USD ($)extension_period	Jul. 31, 2016USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations			$ 87,225,000
Increase to the transaction price			(7,100,000)
Deferred revenue			3,867,193,000	$ 63,310,000
Additions			4,009,960,000
Vertex Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research extension period elected	6 months
Total collaboration revenue	$ 2,000,000		4,500,000
Payment received, research extension period	18 months
Number of extension periods | extension_period	2
Research extension period	1 year
Proceeds from equity investment	$ 20,000,000
Termination period	90 days
Termination period upon marketing approval	180 days
Remaining performance obligations				24,400,000
Increase to the transaction price			8,600,000
Additions		$ 20,000,000
Vertex Agreement | Development Milestones
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Estimated arrangement consideration	$ 55,000,000
Vertex Agreement | Regulatory Milestones
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Estimated arrangement consideration	220,000,000
Vertex Agreement | Regulatory Milestones, Subsequent Products
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Estimated arrangement consideration	$ 3,000,000
Vertex Agreement | Upfront payment
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations			2,000,000	20,000,000
Vertex Agreement | Research and development
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations			$ 2,500,000	$ 4,400,000

Collaboration Agreements - VE_4

Collaboration Agreements - VERTEX Composition of the Total Transaction Price (Details) $ in Thousands	Dec. 31, 2020USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 87,225
Vertex First Extended Research Term
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	43,798
Vertex First Extended Research Term | Upfront payment
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	4,000
Vertex First Extended Research Term | Research and development
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 39,798

Collaboration Agreements - VE_5

Collaboration Agreements - VERTEX Total Transaction Price to the Identified Performance Obligations (Details) $ in Thousands	Dec. 31, 2020USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 87,225
Vertex First Extended Research Term
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	43,798
Vertex First Extended Research Term | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 30,346

Collaboration Agreements - VE_6

Collaboration Agreements - VERTEX Revenue Recognized (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Vertex First Extended Research Term
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue recognized	$ 13,452	$ 0	$ 0
Vertex Agreement/2019 Amendment
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue recognized	2,053	6,197	10,400
Vertex Agreements
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue recognized	$ 15,505	$ 6,197	$ 10,400

Collaboration Agreements - VE_7

Collaboration Agreements - VERTEX Balances of Deferred Revenue (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Contract with customer, liability	$ 4,044,612	$ 202,305
Vertex Agreements 1
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Contract with customer, liability	$ 2,648	$ 793

Collaboration Agreements - Ve_8

Collaboration Agreements - Vertex 2020 Strategic Alliance in Cystic Fibrosis (Details) - USD ($) $ in Thousands	1 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Remaining performance obligations	$ 87,225
Deferred revenue	$ 3,867,193	$ 63,310
Vertex 2020 Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Initial research period	3 years
Total collaboration revenue	$ 75,000
Written notice period	90 days
Termination period	180 days
Remaining performance obligations	$ 75,000
Deferred revenue	75,000
Vertex 2020 Agreement | Upfront payment
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total collaboration revenue	75,000
Vertex 2020 Agreement | Certain Development Regulatory And Commercial Milestone Events
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Amounts included in contract liabilities at the beginning of the period	$ 380,000

Collaboration Agreements - Chie

Collaboration Agreements - Chiesi Agreement Composition of the Total Transaction Price (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 87,225	$ 87,225
Contract with Customer, Liability, Noncurrent	$ 177,419	177,419	$ 138,995
Chiesi agreement
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Initial research period	4 years
Total collaboration revenue		$ 200
Research extension period elected		1 year
Research extension period	4 years
Remaining performance obligations	$ 42,496	$ 42,496
Amounts included in contract liabilities at the beginning of the period		25,000
Contract with Customer, Liability, Noncurrent	25,000	25,000
Chiesi agreement | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	17,300	17,300
Chiesi agreement | Upfront payment
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total collaboration revenue		25,000
Remaining performance obligations	25,000	$ 25,000
Chiesi agreement | Certain Development Regulatory And Commercial Milestone Events
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Amounts included in contract liabilities at the beginning of the period	$ 405,000

Collaboration Agreements - Ch_2

Collaboration Agreements - Chiesi Agreement Total Transaction Price to the Identified Performance Obligations (Details) $ in Thousands	Dec. 31, 2020USD ($)
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations	$ 87,225
Chiesi agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations	42,496
Chiesi agreement | Upfront payment
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations	25,000
Chiesi agreement | Research and development
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations	17,496
Chiesi agreement | Chiesi Agreement transaction price
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations	42,496
Chiesi agreement | Remaining unsatisfied performance obligation
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Remaining performance obligations	$ 42,293

Financial Instruments and Fai_3

Financial Instruments and Fair Value Measurements - Summary of Cash and Available-for-Sale Securities by Significant Investment Category (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 2,618,345	$ 1,024,106
Level 2
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	5,242,194	1,259,980
Unrealized Gains	4,413	3,047
Unrealized Losses	(151)	(40)
Fair Value	5,246,456	1,262,987
Level 2 | Cash and Cash Equivalents
Debt Securities, Available-for-sale [Line Items]
Fair Value	2,623,850	235,876
Level 2 | Current Marketable Securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	1,983,758	867,124
Level 2 | Non- Current Marketable Securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	638,848	159,987
Cash and Cash Equivalents | Level 1
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	2,623,849	225,874
Unrealized Gains	1	0
Unrealized Losses	0	0
Fair Value	2,623,850	225,874
Cash and Cash Equivalents | Level 1 | Cash and Cash Equivalents
Debt Securities, Available-for-sale [Line Items]
Fair Value	2,623,850	225,874
Cash and Cash Equivalents | Level 1 | Current Marketable Securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	0	0
Cash and Cash Equivalents | Level 1 | Non- Current Marketable Securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	0	0
Certificates of deposit | Level 2
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	238,774	82,028
Unrealized Gains	49	79
Unrealized Losses	(4)	(6)
Fair Value	238,819	82,101
Certificates of deposit | Level 2 | Cash and Cash Equivalents
Debt Securities, Available-for-sale [Line Items]
Fair Value	0	10,002
Certificates of deposit | Level 2 | Current Marketable Securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	215,389	69,197
Certificates of deposit | Level 2 | Non- Current Marketable Securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	23,430	2,902
U.S. treasury securities | Level 2
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	491,549	117,891
Unrealized Gains	69	260
Unrealized Losses	0	(2)
Fair Value	491,618	118,149
U.S. treasury securities | Level 2 | Cash and Cash Equivalents
Debt Securities, Available-for-sale [Line Items]
Fair Value	0	0
U.S. treasury securities | Level 2 | Current Marketable Securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	491,618	110,186
U.S. treasury securities | Level 2 | Non- Current Marketable Securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	0	7,963
Debt securities of U.S. government agencies and corporate entities | Level 2
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,888,022	834,187
Unrealized Gains	4,294	2,708
Unrealized Losses	(147)	(32)
Fair Value	1,892,169	836,863
Debt securities of U.S. government agencies and corporate entities | Level 2 | Cash and Cash Equivalents
Debt Securities, Available-for-sale [Line Items]
Fair Value	0	0
Debt securities of U.S. government agencies and corporate entities | Level 2 | Current Marketable Securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	1,276,751	687,741
Debt securities of U.S. government agencies and corporate entities | Level 2 | Non- Current Marketable Securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	$ 615,418	$ 149,122

Financial Instruments and Fai_4

Financial Instruments and Fair Value Measurements - Amortized Cost and Estimated Fair Value of Marketable Securities, by Contractual Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Amortized Cost
Due in one year or less	$ 1,980,963	$ 864,958
Due after one year through five years	637,382	159,148
Amortized Cost	2,618,345	1,024,106
Estimated Fair Value
Due in one year or less	1,983,758	867,124
Due after one year through five years	638,848	159,987
Total	$ 2,622,606	$ 1,027,111

Financial Instruments and Fai_5

Financial Instruments and Fair Value Measurements - Unrealized Loss Position (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Losses, Less than 12 months	$ (152)	$ (40)
Estimated Fair Value, Less than 12 months	588,540	85,161
Gross Unrealized Losses, 12 months or more	0	0
Estimated Fair Value, 12 months or more	0	0
Gross Unrealized Losses, Total	(152)	(40)
Estimated Fair Value, Total	588,540	85,161
Certificates of deposit
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Losses, Less than 12 months	(4)	(6)
Estimated Fair Value, Less than 12 months	81,524	12,822
Gross Unrealized Losses, 12 months or more	0	0
Estimated Fair Value, 12 months or more	0	0
Gross Unrealized Losses, Total	(4)	(6)
Estimated Fair Value, Total	81,524	12,822
U.S. treasury securities
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Losses, Less than 12 months		(2)
Estimated Fair Value, Less than 12 months		9,979
Gross Unrealized Losses, 12 months or more		0
Estimated Fair Value, 12 months or more		0
Gross Unrealized Losses, Total		(2)
Estimated Fair Value, Total		9,979
Debt securities of U.S. government agencies and corporate entities
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Losses, Less than 12 months	(148)	(32)
Estimated Fair Value, Less than 12 months	507,016	62,360
Gross Unrealized Losses, 12 months or more	0	0
Estimated Fair Value, 12 months or more	0	0
Gross Unrealized Losses, Total	(148)	(32)
Estimated Fair Value, Total	$ 507,016	$ 62,360

Financial Instruments and Fai_6

Financial Instruments and Fair Value Measurements - Narrative (Details)	12 Months Ended
	Dec. 31, 2020USD ($)security	Dec. 31, 2019USD ($)security	Dec. 31, 2018USD ($)
Investments, Debt and Equity Securities [Abstract]
Impairment charges related to marketable securities | $	$ 0	$ 0	$ 0
Number of AFS securities | security	108	19

Financial Instruments and Fai_7

Financial Instruments and Fair Value Measurements - Financial Assets Measured At Fair Value On a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Level 2
Debt Securities, Available-for-sale [Line Items]
AFS	$ 5,246,456	$ 1,262,987
Certificates of deposit | Level 2
Debt Securities, Available-for-sale [Line Items]
AFS	238,819	82,101
U.S. treasury securities | Level 2
Debt Securities, Available-for-sale [Line Items]
AFS	491,618	118,149
Debt securities of U.S. government agencies and corporate entities | Level 2
Debt Securities, Available-for-sale [Line Items]
AFS	1,892,169	836,863
Fair value recurring
Debt Securities, Available-for-sale [Line Items]
Derivative instruments	293
Assets, Fair Value Disclosure	3,243,846	1,037,113
Fair value recurring | Level 1
Debt Securities, Available-for-sale [Line Items]
Derivative instruments	0
Assets, Fair Value Disclosure	620,947	0
Fair value recurring | Level 2
Debt Securities, Available-for-sale [Line Items]
Derivative instruments	293
Assets, Fair Value Disclosure	2,622,899	1,037,113
Fair value recurring | Money market funds
Debt Securities, Available-for-sale [Line Items]
AFS	620,947
Fair value recurring | Money market funds | Level 1
Debt Securities, Available-for-sale [Line Items]
AFS	620,947
Fair value recurring | Money market funds | Level 2
Debt Securities, Available-for-sale [Line Items]
AFS	0
Fair value recurring | Certificates of deposit
Debt Securities, Available-for-sale [Line Items]
AFS	238,819	82,101
Fair value recurring | Certificates of deposit | Level 1
Debt Securities, Available-for-sale [Line Items]
AFS	0	0
Fair value recurring | Certificates of deposit | Level 2
Debt Securities, Available-for-sale [Line Items]
AFS	238,819	82,101
Fair value recurring | U.S. treasury securities
Debt Securities, Available-for-sale [Line Items]
AFS	491,618	118,149
Fair value recurring | U.S. treasury securities | Level 1
Debt Securities, Available-for-sale [Line Items]
AFS	0	0
Fair value recurring | U.S. treasury securities | Level 2
Debt Securities, Available-for-sale [Line Items]
AFS	491,618	118,149
Fair value recurring | Debt securities of U.S. government agencies and corporate entities
Debt Securities, Available-for-sale [Line Items]
AFS	1,892,169	836,863
Fair value recurring | Debt securities of U.S. government agencies and corporate entities | Level 1
Debt Securities, Available-for-sale [Line Items]
AFS	0	0
Fair value recurring | Debt securities of U.S. government agencies and corporate entities | Level 2
Debt Securities, Available-for-sale [Line Items]
AFS	$ 1,892,169	$ 836,863

Derivative Financial Instrume_3

Derivative Financial Instruments - Balance Sheet Hedges (Details) - Not Designated as Hedging Instrument $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	$ 368,448
Fair value, asset	293
Fair value, liability	0
Foreign currency forward contracts	293
Foreign currency forward contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	368,448
Fair value, asset	293
Fair value, liability	0
Foreign currency forward contracts | Other (expense) income, net
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Foreign currency forward contracts	$ 293

Inventory (Details)

Inventory (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Raw materials	$ 36,222,000
Work in progress	9,015,000
Finished goods	1,290,000
Inventory	$ 46,527,000	$ 0

Property and Equipment (Details

Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 416,550	$ 296,079
Less: Accumulated depreciation	(119,661)	(94,584)
Property and equipment, net	296,889	201,495
Depreciation and amortization	31,251	31,021	$ 24,862
Laboratory equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	120,714	108,257
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	179,901	152,426
Furniture, fixtures and other
Property, Plant and Equipment [Line Items]
Property and equipment, gross	4,662	3,316
Computer equipment and software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	13,398	11,985
Internally developed software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	7,020	7,020
Right-of-use asset, financing
Property, Plant and Equipment [Line Items]
Property and equipment, gross	56,348	9,853
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 34,507	$ 3,222

Other Balance Sheet Component_2

Other Balance Sheet Components - Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Down payments to manufacturing vendors	$ 216,538	$ 0
Prepaid expenses	15,647	8,475
Tenant incentives receivables	10,242	4,093
Interest receivable on marketable securities	9,725	6,835
Prepaid expenses and other current assets	$ 252,152	$ 19,403

Other Balance Sheet Component_3

Other Balance Sheet Components - Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Clinical trials	$ 97,249	$ 6,291
Compensation-related	95,247	27,428
Raw materials	78,085	0
Manufacturing	53,412	5,872
Development operations	29,253	2,567
Property and equipment	17,576	4,029
Commercial	6,922	0
Other external goods and services	91,847	21,465
Accrued liabilities	$ 469,591	$ 67,652

Other Balance Sheet Component_4

Other Balance Sheet Components - Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Lease liabilities - financing	$ 24,328	$ 0
Lease liabilities - operating	5,972	3,583
Other	3,365	1,480
Other current liabilities	$ 33,665	$ 5,063

Other Balance Sheet Component_5

Other Balance Sheet Components - Deferred Revenue (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)
Change In Contract With Customer, Liability [Roll Forward]
Beginning balance	$ 202,305
Additions	4,009,960
Deductions	(167,653)
Ending balance	4,044,612
Product sales
Change In Contract With Customer, Liability [Roll Forward]
Beginning balance	0
Additions	3,881,303
Deductions	(82,134)
Ending balance	3,799,169
Grant revenue
Change In Contract With Customer, Liability [Roll Forward]
Beginning balance	2,777
Additions	6,775
Deductions	(4,291)
Ending balance	5,261
Collaboration revenue
Change In Contract With Customer, Liability [Roll Forward]
Beginning balance	199,528
Additions	121,882
Deductions	(81,228)
Ending balance	$ 240,182

Leases - Narrative (Details)

Leases - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)ft²campus	Dec. 31, 2018USD ($)	Jun. 01, 2020ft²	Dec. 31, 2019USD ($)	Aug. 31, 2019ft²	Feb. 28, 2019ft²extension_period	Aug. 31, 2016ft²extension_period
Lessee, Lease, Description [Line Items]
Number of campuses | campus	2
Lease liabilities	$ 103,393
Right-of-use assets, operating leases	90,201			$ 86,414
Rent expense		$ 19,100
Amounts representing interest or imputed interest, operating lease	70,354
Amounts representing interest or imputed interest, finance lease	379,110
Embedded Leases
Lessee, Lease, Description [Line Items]
Lease liabilities	24,300
Right-of-use assets, operating leases	$ 62,300
Cambridge Leases
Lessee, Lease, Description [Line Items]
Area of office space (in sqft) | ft²	175,000
Cambridge Leases | 200 Technology Square
Lessee, Lease, Description [Line Items]
Area of office space (in sqft) | ft²					50,000
Extension term					2 years
Cambridge Leases | 500 Technology Square
Lessee, Lease, Description [Line Items]
Area of office space (in sqft) | ft²					60,000
Norwood Leases
Lessee, Lease, Description [Line Items]
Area of office space (in sqft) | ft²						200,000
Extension term						5 years	10 years
Number of extension periods | extension_period						4	2
Percentage subleased						64.00%
Tenant improvements	$ 22,200
Norwood Leases | Office, laboratory, and light manufacturing space
Lessee, Lease, Description [Line Items]
Area of office space (in sqft) | ft²							200,000
Amounts representing interest or imputed interest, finance lease	$ 338,900
Norwood Leases | MTC North [Member]
Lessee, Lease, Description [Line Items]
Percentage subleased			12.00%
Additional space (in sqft) | ft²			28,000
Incremental borrowing rate	8.20%
Norwood Leases | MTC South
Lessee, Lease, Description [Line Items]
Imputed interest rate	17.20%

Leases - Balance Sheet Informat

Leases - Balance Sheet Information (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Right-of-use assets, operating, net	$ 90,201	$ 86,414
Right-of-use assets, financing, net	55,045	9,544
Total	145,246	95,958
Operating lease liabilities	5,972	3,583
Financing lease liabilities	24,328	0
Total current liabilities	30,300	3,583
Operating lease liabilities, non-current	97,421	93,675
Financing lease liabilities, non-current	109,874	38,689
Total non-current lease liabilities	207,295	132,364
Total	$ 237,595	$ 135,947
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesCurrent	us-gaap:OtherLiabilitiesCurrent
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesCurrent	us-gaap:OtherLiabilitiesCurrent
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization	us-gaap:PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization

Leases - Lease Costs (Details)

Leases - Lease Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease costs	$ 16,939	$ 17,015
Amortization of right-of-use assets, financing leases	1,011	309
Interest expense for financing lease liabilities	9,891	6,557
Total financing lease costs	10,902	6,866
Short term lease costs	13,322	0
Variable lease costs	5,229	4,399
Operating cash flows used in operating leases	(15,089)	(16,121)
Operating cash flows used in financing leases	(8,523)	(5,585)
Financing cash flows used in financing leases	(7,519)	0
Right-of-use assets reduced through lease modifications and reassessments	6,755	2,717
Right-of-use assets obtained in exchange for operating lease liabilities	17,107	34,014
Right-of-use assets obtained through lease modifications and reassessments	46,495	0
Charge to financing lease obligation	$ 1,304	$ 971
Operating leases, remaining lease term	11 years
Finance leases, remaining lease term	25 years
Operating leases, discount rate	10.30%
Finance leases, discount rate	13.10%

Leases - Minimum Lease Payments

Leases - Minimum Lease Payments (Details) $ in Thousands	Dec. 31, 2020USD ($)
Operating Leases
2021	$ 15,492
2022	15,913
2023	16,008
2024	16,168
2025	16,567
Thereafter	93,599
Total minimum lease payments	173,747
Less amounts representing interest or imputed interest	(70,354)
Present value of lease liabilities	103,393
Financing Leases
2021	36,579
2022	11,848
2023	12,054
2024	12,279
2025	12,493
Thereafter	428,059
Total minimum lease payments	513,312
Less amounts representing interest or imputed interest	(379,110)
Present value of lease liabilities	$ 134,202

Commitments and Contingencies -

Commitments and Contingencies - Strategic Collaborations (Details) - PCV Agreement - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Apr. 30, 2018	Jun. 30, 2017
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Budgeted amount				$ 250
PCV products
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Budgeted amount	$ 243	$ 243	$ 243

Commitments and Contingencies_2

Commitments and Contingencies - Indemnification Obligations (Details) - Indemnifications	12 Months Ended
	Dec. 31, 2020USD ($)claim	Dec. 31, 2019USD ($)claim
Loss Contingencies [Line Items]
Losses related to indemnification obligations	$ 0	$ 0
Number of claims outstanding | claim	0	0
Reserves established	$ 0	$ 0

Commitments and Contingencies_3

Commitments and Contingencies - Purchase Commitments and Purchase Orders (Details) $ in Millions	Dec. 31, 2020USD ($)
Supply and manufacturing agreements
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Contractual commitment to pay	$ 659,500
Clinical services
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Contractual commitment to pay	27
Clinical operations and support commitments
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Contractual commitment to pay	$ 896.9

Commitments and Contingencies_4

Commitments and Contingencies - Licenses to Patented Technology (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2018	Jun. 26, 2017
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Commercial milestone payments			$ 24
Consideration paid	$ 6.9
Sublicense agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Expenses associated with license agreements		$ 22
Therapeutic and prophylactic products
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Development and regulatory milestone payments			1.5
Diagnostic products
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Development and regulatory milestone payments			$ 0.5

Redeemable Convertible Prefer_2

Redeemable Convertible Preferred Stock and Common Stock - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	May 21, 2020	Feb. 14, 2020	Dec. 11, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	May 07, 2018	Feb. 28, 2018
Subsidiary, Sale of Stock [Line Items]
Common stock, shares authorized (in shares)			1,600,000,000	1,600,000,000	1,600,000,000			775,000,000
Redeemable convertible preferred stock, shares authorized							509,352,795
Common stock, par value (usd per share)			$ 0.0001	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)			162,000,000	162,000,000	162,000,000
Preferred stock, par value (usd per share)			$ 0.0001	$ 0.0001	$ 0.0001
Shares of common stock issued (in shares)	17,600,000	30,263,158
Price per share (usd per share)	$ 76	$ 19
Offering expenses				$ 2,120		$ 41,322
Redeemable convertible preferred stock, shares issued				0	0
Redeemable convertible preferred stock, shares outstanding				0	0
Proceeds from public offering				$ 1,852,725	$ 0	$ 563,026
IPO
Subsidiary, Sale of Stock [Line Items]
Shares of common stock issued (in shares)			26,275,993
Price per share (usd per share)			$ 23
Underwriting discounts			$ 33,200
Offering expenses			8,100
Proceeds from public offering			$ 563,000
IPO | Common Stock
Subsidiary, Sale of Stock [Line Items]
Preferred stock converted into common stock (in shares)			236,012,913
Public Equity Offering
Subsidiary, Sale of Stock [Line Items]
Shares of common stock issued (in shares)	17,600,000	26,315,790
Price per share (usd per share)	$ 76	$ 19
Proceeds from public offering	$ 1,300,000	$ 477,700
Underwriting Option
Subsidiary, Sale of Stock [Line Items]
Shares of common stock issued (in shares)		3,947,368
Proceeds from public offering		$ 71,800

Stock-Based Compensation - Narr

Stock-Based Compensation - Narrative (Details) $ / shares in Units, $ in Thousands	Dec. 05, 2018USD ($)purchase_periodofferingshares	Nov. 30, 2018shares	Dec. 31, 2020USD ($)installment$ / sharesshares	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate number of shares authorized for issuance (in shares) | shares			64,200,000
Total intrinsic value of options exercised (less than for the year ended December 31, 2017)			$ 785,700	$ 75,600	$ 5,300
Consideration for options exercised			179,600
Restricted stock unit			5,000	5,500	0
Compensation costs			93,021	81,122	72,565
Total unrecognized compensation cost related to non-vested stock-based compensation			$ 226,800
Weighted-average period of cost expected to be recognized			2 years 10 months 24 days
Service-based awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			4 years
Service-based awards | Twelve months of continued employment or service
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			12 months
Vesting percentage			25.00%
Service-based awards | Following twelve quarters
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			36 months
Number of installments | installment			12
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate number of shares authorized for issuance (in shares) | shares			36,300,000
Compensation costs			$ 77,748	74,780	63,288
Employee stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation costs			2,872	1,217	0
Performance-based awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation costs			$ 9,600	$ 9,800	$ 10,600
2018 Equity Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate number of shares authorized for issuance (in shares) | shares		13,000,000
Annual percentage increase of shares reserved and available for issuance		4.00%
Shares available for future grant (in shares) | shares			27,900,000
2016 Equity Plan | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period			10 years
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share available for future issuance (in shares) | shares			3,600,000
ESPP | Employee stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate number of shares authorized for issuance (in shares) | shares	810,000
Offering period | offering	1
Purchase period | purchase_period	1
Purchase price at which shares are sold, percent	85.00%
Minimum percentage of compensation through payroll deductions	1.00%
Maximum percentage of compensation through payroll deductions	50.00%
Maximum shares to be purchased during purchase period (in shares) | shares	3,000
Maximum value of shares to be purchased during purchase period	$ 25,000
Purchase of common stock under employee stock purchase plan (in shares) | shares			251,752
Weighted average fair value per share (usd per share) | $ / shares			$ 27.97
Share-Based Compensation Arrangement By Share-Based Payment Award, Purchase Period	6 months
Share-Based Compensation Arrangement By Share-Based Payment Award, Consecutive Offering Period	6 months

Stock-Based Compensation - Opti

Stock-Based Compensation - Options Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Number of Options
Outstanding at beginning of period (in shares)	45,536,915
Granted (in shares)	5,036,520
Exercised (in shares)	(13,888,434)
Cancelled/forfeited (in shares)	(2,627,468)
Outstanding at end of period (in shares)	34,057,533	45,536,915
Weighted Average Exercise Price per Share
Outstanding at beginning of period (usd per share)	$ 13.82
Granted (usd per share)	36.04
Exercised (usd per share)	12.93
Cancelled/forfeited (usd per share)	18.14
Outstanding at end of period (usd per share)	17.14	$ 13.82
Weighted Average Grant Date Fair Value per Share
Outstanding at beginning of period (usd per share)	7.35
Granted (usd per share)	19.30
Exercised (usd per share)	6.68
Cancelled/forfeited (usd per share)	10.56
Outstanding at end of period (usd per share)	$ 9.12	$ 7.35
Outstanding and Exercisable
Number of Options, Exercisable (in shares)	17,461,374
Weighted- Average Exercise Price per Share, Exercisable (usd per share)	$ 10.99
Weighted- Average Grant Date Fair Value per Share, Exercisable (usd per share)	$ 5.67
Weighted- Average Remaining Contractual Term, Outstanding	6 years 8 months 12 days	7 years 2 months 12 days
Weighted- Average Remaining Contractual Term, Exercisable	5 years 4 months 24 days
Aggregate Intrinsic Value, Outstanding	$ 2,976,235	$ 286,310
Aggregate Intrinsic Value, Exercisable	$ 1,632,365
Vested and expected to vest
Number of Options (in shares)	16,596,159
Weighted- Average Exercise Price per Share (usd per share)	$ 23.61
Weighted- Average Grant Date Fair Value per Share	$ 12.75
Weighted- Average Remaining Contractual Term	8 years 2 months 12 days
Aggregate Intrinsic Value	$ 1,343,870

Stock-Based Compensation - Rest

Stock-Based Compensation - Restricted Common Stock and Common Stock Units Activity (Details) - Restricted Common Stock Units	12 Months Ended
	Dec. 31, 2020$ / sharesshares
Number of Shares/Units
Outstanding, non-vested at beginning of period (in shares) | shares	1,177,249
Issued (in shares) | shares	1,478,093
Vested (in shares) | shares	(247,349)
Cancelled/forfeited (in shares) | shares	(215,033)
Outstanding, non-vested at end of period (in shares) | shares	2,192,960
Weighted-Average Grant Date per Share/Unit
Outstanding, non-vested at beginning of period (usd per share) | $ / shares	$ 19.01
Issued (usd per share) | $ / shares	37.37
Vested (usd per share) | $ / shares	20.28
Cancelled/forfeited (usd per share) | $ / shares	23.64
Outstanding, non-vested at end of period (usd per share) | $ / shares	$ 30.85

Stock-Based Compensation - Weig

Stock-Based Compensation - Weighted-Average Assumptions Used to Estimate the Fair Value of Options Granted (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	0.83%	2.29%	2.76%
Expected term	6 years 1 month 9 days	6 years 25 days	6 years 3 months 7 days
Expected volatility	58.00%	61.00%	63.00%
Expected dividends	0.00%	0.00%	0.00%
Options | Weighted Average
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average fair value per share (usd per share)	$ 19.30	$ 11.35	$ 9.33
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	0.14%	1.95%
Expected term	6 months	6 months
Expected volatility	54.00%	53.00%
Expected dividends	0.00%	0.00%
ESPP | Weighted Average
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average fair value per share (usd per share)	$ 32.18	$ 5.98

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 93,021	$ 81,122	$ 72,565
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	56,155	48,259	37,659
Selling, general and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	36,866	32,863	34,906
Options
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	77,748	74,780	63,288
Restricted common stock and units
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	12,401	5,125	9,277
Employee stock purchase plan
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 2,872	$ 1,217	$ 0

Employee Benefit Plan (Details)

Employee Benefit Plan (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Retirement Benefits [Abstract]
Percent of match	50.00%
Percent contributed by participant	6.00%
Total matching contributions	$ 5	$ 4.2	$ 2.1

Income Taxes - Loss Before Prov

Income Taxes - Loss Before Provision For (Benefit From) Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
United States	$ (745,445)	$ (508,595)	$ (380,473)
Foreign	932	(6,121)	(3,935)
Loss before provision for (benefit from) income taxes	$ (744,513)	$ (514,716)	$ (384,408)

Income Taxes - Provision For (B

Income Taxes - Provision For (Benefit From) Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current:
Federal	$ 0	$ 0	$ (26)
State	32	505	352
Foreign	2,519	0	0
Total current	2,551	505	326
Deferred:
Federal	0	(1,200)	0
Total deferred	0	(1,200)	0
Total provision for (benefit from) income taxes	$ 2,551	$ (695)	$ 326

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of U.S. Statutory Income Tax Rate to Effective Tax Rate (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Tax effected at statutory rate	21.00%	21.00%	21.00%
State taxes, net of federal benefit	3.60%	7.90%	6.30%
Non-deductible items	(0.80%)	1.60%	0.00%
Change in valuation allowance	(47.40%)	(33.00%)	(28.50%)
Federal research and development credits	3.80%	2.50%	1.50%
Foreign tax rate differential	0.00%	(0.20%)	(0.20%)
Stock compensation windfall	19.80%	0.00%	0.00%
Other	(0.30%)	0.20%	(0.20%)
Effective tax rate	(0.30%)	(0.00%)	(0.10%)

Income Taxes - Significant Comp

Income Taxes - Significant Components of Deferred Tax Assets and Tax Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Net operating loss carry-forwards	$ 587,211	$ 268,173
Stock-based compensation	33,089	43,978
Capitalized licenses, research and development and start-up costs	13,985	19,891
Tax credit carry-forwards	99,024	77,222
Accrued expenses	26,962	7,377
Deferred revenue	29,785	53,475
Operating lease liabilities	22,313	26,571
Lease financing obligation	23,718	10,570
Capitalized inventory	38,058	0
Other	0	11
Total gross deferred tax assets	874,145	507,268
Less: valuation allowance	(823,468)	(470,753)
Total deferred tax assets, net of valuation allowance	50,677	36,515
Deferred tax liabilities:
Financing right-of-use assets	(11,539)	(2,612)
Operating right-of-use assets	(20,349)	(24,944)
Fixed assets	(18,276)	(8,959)
Other	(513)	0
Total deferred tax liabilities	(50,677)	(36,515)
Net deferred tax assets	$ 0	$ 0

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Increase in valuation allowance	$ 352,700
Operating Loss Carryforwards [Line Items]
Increase in valuation allowance	352,700
Deferred tax assets	874,145	$ 507,268
Federal
Operating Loss Carryforwards [Line Items]
Net operating losses	2,260,000
Net operating losses that begin to expire in 2030	380,100
Net operating losses that will carry-forward indefinitely	1,880,000
Federal | Research and development
Operating Loss Carryforwards [Line Items]
Tax credit carry-forwards	73,300
State
Operating Loss Carryforwards [Line Items]
Net operating losses	1,700,000
Net operating losses that begin to expire in 2030	1,700,000
State | Research and development
Operating Loss Carryforwards [Line Items]
Tax credit carry-forwards	26,100
State | Federal Orphan Drug
Operating Loss Carryforwards [Line Items]
Tax credit carry-forwards	2,000
State | Investment tax credit
Operating Loss Carryforwards [Line Items]
Tax credit carry-forwards	$ 3,900

Income Taxes - Reconciliation_2

Income Taxes - Reconciliation of the Beginning and Ending Amounts of Unrecognized Tax Benefits Roll Forward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance as of beginning of period	$ 141	$ 141
Decrease due to prior positions	0	0
Increase due to current year tax positions	0	0
Balance as of end of period	$ 141	$ 141

Net Loss per Share - Basic and

Net Loss per Share - Basic and Diluted Net Loss per Share Attributable to Common Stockholders (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Numerator:
Net loss	$ (747,064)	$ (514,021)	$ (384,734)
Premium paid on repurchase of preferred stock	0	0	(4,127)
Cumulative dividends on redeemable convertible preferred stock	0	0	(12,996)
Net loss attributable to common stockholders	$ (747,064)	$ (514,021)	$ (401,857)
Denominator:
Weighted average common shares used in net loss per share attributable to common stockholders, basic and diluted (in shares)	381,333,059	330,802,136	81,114,183
Net loss per share attributable to common stockholders, basic and diluted (usd per share)	$ (1.96)	$ (1.55)	$ (4.95)

Net Loss per Share - Common Sto

Net Loss per Share - Common Stock Equivalents Excluded from Calculation of Diluted Net Loss Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	36,250,493	46,714,164	51,478,444
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	34,057,533	45,536,915	50,821,132
Restricted common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	0	0	198,597
Restricted common stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	2,192,960	1,177,249	458,715

Geographic Information (Details

Geographic Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)segment	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Revenue from Contract with Customer [Abstract]
Number of operating segments | segment	1
Disaggregation of Revenue [Line Items]
Revenues	$ 803,395	$ 60,209	$ 135,068
United States
Disaggregation of Revenue [Line Items]
Revenues	764,529	54,976	89,075
Rest of world
Disaggregation of Revenue [Line Items]
Revenues	$ 38,866	$ 5,233	$ 45,993

Subsequent Events (Details)

Subsequent Events (Details) - Subsequent Event dose in Millions, $ in Millions	Feb. 18, 2021numberOfDose	Feb. 26, 2021USD ($)dose
Subsequent Event [Line Items]
Number of doses of vaccine candidate | dose		125.1
Supply commitment		$ 125.4
Number of vaccine doses | numberOfDose	150,000,000
Contractual commitment to pay		$ 314.8