Description of the Business and Liquidity (Details) $ in Thousands, € in Millions				1 Months Ended		3 Months Ended
	Jul. 30, 2021 USD ($)	Jul. 30, 2021 EUR (€)	May 11, 2021 USD ($) tranche	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Mar. 31, 2022 USD ($) shares	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($) shares
Liquidity
Net loss						$ 19,361	$ 27,141
Accumulated deficit						430,066		$ 410,705
Proceeds from Lines of Credit						$ 75,000
Common stock, shares authorized | shares						150,000,000		150,000,000
Oaktree Capital Management LP Credit Agreement
Liquidity
Term of loan facility			5 years
Maximum borrowing capacity available under the credit agreement			$ 125,000
Number of tranches | tranche			5
Proceeds from Lines of Credit			$ 15,000	$ 30,000		$ 30,000
Additional borrowing capacity available, subject to certain milestone events			$ 50,000
Oaktree Capital Management LP Credit Agreement | Funding of the tranche A- 2 term loans until the funding of the tranche B term loans
Liquidity
Minimum liquidity to be maintained						15,000
BARDA Contract
Liquidity
Maximum amount to be awarded under the contract					$ 51,000
Contract base period					2 years
Amount of funding to be provided during contract base period					$ 21,000
Amount of additional funding to be provided following successful completion of clinical trial and preclinical studies in base period					30,000
Cost sharing, amount					33,000
Cost sharing, BARDA amount					$ 51,000
Contract period-of-performance					5 years
Collaboration Agreement with Orion
Liquidity
Upfront fee received	$ 29,600	€ 25.0
R&D reimbursement and cash milestone payments to be received | €		€ 97.0
Number of days from receipt of the final report, in which the collaboration agreement may be terminated	90 days	90 days
Percentage of upfront fee which must be refunded in the event of termination		75.00%
Term Loan Tranche B | Oaktree Capital Management LP Credit Agreement
Liquidity
Proceeds from Lines of Credit						$ 30,000
Common Stock
Liquidity
Issuance of common stock (in shares) | shares						123,255