Commitments and Contingencies - Additional Information (Detail) $ in Thousands		1 Months Ended	3 Months Ended
	Aug. 20, 2019 USD ($)	Jul. 31, 2019 agreement	Mar. 31, 2022 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)
Other Commitments [Line Items]
Research and development expense			$ 21,273	$ 19,131
Lease term			1 year 9 months 18 days	2 years 9 months 18 days
Operating lease liabilities			$ 3,250
Operating lease right-of-use assets			2,629		$ 2,973
Enteris Biopharma, Inc. [Member]
Other Commitments [Line Items]
Payment of milestone payment			0	$ 0
Payments for Royalties			0	0
Stamford Operating Lease and New Stamford Lease [Member]
Other Commitments [Line Items]
Operating lease cost			406	406
Stamford Operating Lease and New Stamford Lease [Member] | Research and Development [Member]
Other Commitments [Line Items]
Operating lease cost			284	284
Stamford Operating Lease and New Stamford Lease [Member] | General and Administrative [Member]
Other Commitments [Line Items]
Operating lease cost			$ 122	$ 122
Non-Exclusive License Agreement | Enteris Biopharma, Inc. [Member]
Other Commitments [Line Items]
Upfront fee	$ 8,000
Upfront fee payment, cash	4,000
Upfront fee payment, stock	$ 4,000
MSA [Member] | Patheon and Patheon Manufacturing Services LLC [Member]
Other Commitments [Line Items]
Number of related product agreements | agreement		2
API Commercial Supply Agreement - PPL [Member]
Other Commitments [Line Items]
Agreement renewal term			5 years