Leases - Additional Information (Detail)	1 Months Ended	3 Months Ended	6 Months Ended
	Jun. 30, 2018 ft²	Jun. 30, 2019 USD ($)	Jun. 30, 2019 USD ($) ft² Tranche
Disclosure of Leases [Line Items]
Loan facility term			5 years
Operating lease weighted average remaining lease term		5 years 8 months 12 days	5 years 8 months 12 days
Operating lease weighted average discount rate		12.50%	12.50%
Operating lease expense		$ 213,000	$ 427,000
Variable lease cost		9,000	18,000
Operating lease payments		205,000	$ 383,000
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
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%