Summary of Significant Accounting Policies - Additional Information (Details)			1 Months Ended		12 Months Ended
	Oct. 01, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jul. 31, 2020 USD ($)	Sep. 30, 2015 USD ($)	Dec. 31, 2020 USD ($) segment $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 shares
Summary of Significant Accounting Policies [Line Items]
Restricted cash current		$ 2,947,000			$ 93,880,000	$ 2,947,000
Purchase price held in escrow		1,500,000				1,500,000
Revenue from contract with customer				$ 89,100,000
Accounts receivable		7,500,000			262,012,000	7,500,000
Deferred revenue		1,678,000			273,228,000	$ 1,678,000
Remaining performance obligation to be satisfied					$ 1,800,000,000
Number of reporting units | segment					1
Impairment to goodwill	$ 0	0
Number of shares excluded from the computation of net loss per share (in shares) | shares					6,679,629,000	4,992,792,000	2,975,481,000
Foreign currency translation adjustment		(12,500,000)			$ 7,000,000.0	$ (12,500,000)
Number of operating segments | segment					1
Government contracts
Summary of Significant Accounting Policies [Line Items]
Revenue from contract with customer					$ 1,800,000,000
Maximum
Summary of Significant Accounting Policies [Line Items]
Intangible assets useful life					20 years
Vesting period					4 years
Minimum
Summary of Significant Accounting Policies [Line Items]
Property and equipment useful life					3 years
Intangible assets useful life					7 years
Vesting period					1 year
Coalition for Epidemic Preparedness Innovations ("CEPI")
Summary of Significant Accounting Policies [Line Items]
Contract to perform for others funding					$ 399,500,000
Contract to perform for others grant					257,000,000.0
Contract to perform for others forgivable no interest term loans					142,500,000
Project Agreement | Government contracts
Summary of Significant Accounting Policies [Line Items]
Revenue from contract with customer			$ 1,700,000,000
Remaining performance obligation to be satisfied					$ 1,500,000,000
Convertible Debt Securities
Summary of Significant Accounting Policies [Line Items]
Number of shares excluded from the computation of net loss per share (in shares) | shares					2,385,800	2,385,800
Convertible notes initial conversion price (in usd per share) | $ / shares					$ 136.20	$ 136.20
Security Deposit
Summary of Significant Accounting Policies [Line Items]
Restricted cash current		400,000			$ 1,500,000	$ 400,000
Bill Melinda Gates Foundation
Summary of Significant Accounting Policies [Line Items]
Restricted cash current and non current		$ 1,400,000			1,500,000	$ 1,400,000
Coalition for Epidemic Preparedness Innovations ("CEPI")
Summary of Significant Accounting Policies [Line Items]
Restricted cash current					$ 92,400,000