Commitments and Contingencies (Details Textual) $ in Millions				1 Months Ended		3 Months Ended		9 Months Ended
	Oct. 02, 2020 USD ($) Installment	Jul. 13, 2019 USD ($)	Jul. 12, 2019 USD ($)	Feb. 29, 2020	Oct. 31, 2017 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Oct. 02, 2020 SGD ($)	Mar. 04, 2020 USD ($)	Mar. 04, 2020 SGD ($)
Commitment And Contingencies [Line Items]
Operating lease extended additional term				13 months
Operating lease, remaining lease term						4 years 3 months 18 days		4 years 3 months 18 days
Lessee, operating lease, term of contract				1 month
Lessee, operating leases, option to extend				The lease may be extended for one twelve-month period, and in November 2020 the Company deemed the extension option reasonably certain to be exercised and will include the option in the lease terms beginning in October 2020.
Operating lease costs						$ 500,000	$ 300,000	$ 1,300,000	$ 900,000
COVID-19 Vaccine Development [Member]
Commitment And Contingencies [Line Items]
Contra research and development expense recognized						3,700,000		7,900,000
Contra expense remaining amount included in accrued expenses						2,100,000		2,100,000
COVID-19 Vaccine Development [Member] | Subsequent Event [Member]
Commitment And Contingencies [Line Items]
Grant, number of installments | Installment	2
Underlying Agreement [Member] | Cystic Fibrosis Foundation [Member]
Commitment And Contingencies [Line Items]
Contra expense remaining amount included in accrued expenses						4,200,000		4,200,000
Payments for matching funds for remaining budgeted costs		$ 5,000,000
Disbursed amount upon execution of amendment		4,000,000
Final payment of disbursement amount		3,000,000
Disbursement payment upon achievement of required manufacturing practices and IND application		2,300,000
Contra expense included in research and development expense						$ 700,000	$ 700,000	$ 3,700,000	$ 700,000
Underlying Agreement [Member] | Cystic Fibrosis Foundation [Member] | Disbursement Due January 2020 [Member]
Commitment And Contingencies [Line Items]
Disbursement amount payable upon achievement of project goal		2,000,000
Underlying Agreement [Member] | Cystic Fibrosis Foundation [Member] | Disbursement Due April 2020 [Member]
Commitment And Contingencies [Line Items]
Disbursement amount payable upon achievement of project goal		2,000,000
Underlying Agreement [Member] | Cystic Fibrosis Foundation [Member] | Disbursement Due July 2020 [Member]
Commitment And Contingencies [Line Items]
Disbursement amount payable upon achievement of project goal		2,000,000
Underlying Agreement [Member] | Cystic Fibrosis Foundation [Member] | Disbursement Due October 2020 [Member]
Commitment And Contingencies [Line Items]
Disbursement amount payable upon achievement of project goal		2,000,000
Underlying Agreement [Member] | LUNAR-CF [Member] | Cystic Fibrosis Foundation [Member]
Commitment And Contingencies [Line Items]
Payments for advance		$ 15,000,000	$ 3,200,000
October 2017 Lease Amendment [Member]
Commitment And Contingencies [Line Items]
Operating lease extended additional term					84 months
Lessee, operating lease, term of contract					4 months
Tenant improvement allowance					$ 74,000
Lessee, operating leases, option to extend					The lease may be extended for one five-year period at the then current market rate with annual escalations;
Security deposit					$ 96,000
Singapore Economic Development Board [Member] | Maximum [Member]
Commitment And Contingencies [Line Items]
Grant awarded											$ 10,100,000	$ 14.0
Singapore Economic Development Board [Member] | Maximum [Member] | Subsequent Event [Member]
Commitment And Contingencies [Line Items]
Grant awarded	$ 6,700,000									$ 9.3
Singapore Economic Development Board [Member] | Maximum [Member] | COVID-19 Vaccine Development [Member]
Commitment And Contingencies [Line Items]
Grant awarded											$ 10,100,000	$ 14.0
Singapore Economic Development Board [Member] | Maximum [Member] | COVID-19 Vaccine Development [Member] | Subsequent Event [Member]
Commitment And Contingencies [Line Items]
Grant awarded	$ 6,700,000									$ 9.3