Leases - Additional Information (Detail)	1 Months Ended	3 Months Ended		9 Months Ended
	Jun. 30, 2018 ft²	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) ft² Tranche	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Disclosure Of Leases [Line Items]
Loan facility term				5 years
Operating lease weighted average remaining lease term		4 years 6 months		4 years 6 months
Operating lease weighted average discount rate		12.50%		12.50%
Operating lease expense		$ 213,000	$ 213,000	$ 640,000	$ 640,000
Variable lease cost		9,000	9,000	27,000	27,000
Operating lease payments		216,000	$ 210,000	646,000	$ 593,000
Finance lease, amortization expense of ROU asset		13,000		39,000
Interest expense on finance lease liability		2,000		7,000
Finance lease, operating cash flows		2,000		7,000
Finance lease, financing cash flows		15,000		35,000
Finance lease		$ 64,000		$ 64,000		$ 0
Finance lease, weighted average Remaining term		1 year 2 months 12 days		1 year 2 months 12 days
Finance lease, weighted average discount rate, percent		12.50%		12.50%
Caladrius [Member]
Disclosure Of Leases [Line Items]
Additional subleased property office area | ft²	1,381
Basking Ridge Office Space [Member]
Disclosure Of Leases [Line Items]
Number of renewal options | Tranche				2
Laboratory Equipment [Member]
Disclosure Of Leases [Line Items]
Lease term expiration date				Dec. 18, 2021
Massachusetts [Member] | Maximum [Member]
Disclosure Of Leases [Line Items]
Construction allowance		$ 670,750		$ 670,750
Massachusetts [Member] | Original Lease [Member]
Disclosure Of Leases [Line Items]
Area of leased office and laboratory space | ft²				13,650
Original lease term		5 years		5 years
Lease term expiration date				Apr. 30, 2019
Massachusetts [Member] | Second Amendment Lease [Member]
Disclosure Of Leases [Line Items]
Lease term expiration date				May 31, 2025
Lease commencement date				Sep. 10, 2018
Additional lease renewal option period		5 years		5 years
Additional Space leased | ft²				6,590
Irrevocable standby letter of credit		$ 150,000		$ 150,000
NEW JERSEY | Basking Ridge Office Space [Member]
Disclosure Of Leases [Line Items]
Lease term expiration date				Jun. 30, 2022
Lease commencement date				Jul. 31, 2017
Additional lease renewal option period		5 years		5 years
Area of leased office space | ft²				3,000
Lease renewal rate at 95% of market rent at time of renewal				95.00%