Commitments and Contingencies - Additional Information (Detail)	1 Months Ended
	Jan. 31, 2020 USD ($) item	Sep. 30, 2019 USD ($) item	Jun. 30, 2019 USD ($) item	Mar. 31, 2019 USD ($) item	Dec. 31, 2013 USD ($)	Mar. 31, 2020 USD ($)	Feb. 29, 2020 USD ($)	Dec. 31, 2019 USD ($)	May 31, 2019 USD ($)	Mar. 31, 2018 USD ($)
Commitments and Contingencies [Line Items]
Contractual obligation						$ 5,597,000
Facility Lease Incremental Borrowing Rate						5.75%
Prepaid Clinical Trial Deposits						$ 348,000		$ 946,000
Prepaid consulting services deposits						182,000		$ 182,000
Newly Leased Office Space and Manufacturing Facility [Member]
Commitments and Contingencies [Line Items]
Non-cancellable operating lease period					125 months
Lease initial base rent per month					$ 23,000
Total base rent over the term of the lease					$ 3,300,000
Key Clinical Research Trial Obligations
Commitments and Contingencies [Line Items]
Contractual obligation						2,193,000
CRO
Commitments and Contingencies [Line Items]
Contract amount	$ 10,300,000			$ 6,200,000		10,255,000
Amount Incurred Against Contract Obligation						8,314,000
Contractual obligation						1,941,000
Number Of Patients | item	1,034			724
Increase in existing contract	$ 4,100,000
Patient recruitment services company
Commitments and Contingencies [Line Items]
Contract amount		$ 377,000	$ 264,000			718,000	$ 698,000
Amount Incurred Against Contract Obligation						20,000
Contractual obligation						0
Cumulative costs						718,000
Number Of Patients | item		1,034	724
Clinical staff outsourcing firm
Commitments and Contingencies [Line Items]
Contract amount						463,000
Amount Incurred Against Contract Obligation						211,000
Contractual obligation						252,000
BLA consulting services
Commitments and Contingencies [Line Items]
Contract amount						1,100,000				$ 1,200,000
Amount Incurred Against Contract Obligation						69,000
Contractual deposit Commitment										364,000
Prepaid consulting services deposits										$ 182,000
Statistical analysis and programming consulting services
Commitments and Contingencies [Line Items]
Contract amount									$ 578,000
Amount Incurred Against Contract Obligation						228,000
Contractual obligation						$ 350,000