Leases - Additional Information (Detail) $ in Millions		6 Months Ended	9 Months Ended
	Jan. 23, 2023 ft² Tranche	Jun. 30, 2024 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)
Disclosure Of Leases [Line Items]
Operating lease weighted average remaining lease term			12 years 4 months 24 days
Operating lease weighted average discount rate			11.60%
Operating lease payments			$ 0.5	$ 0.6
Massachusetts [Member]
Disclosure Of Leases [Line Items]
Lease description	The lease term, under ASC 842, commenced during the second quarter of 2024. The Company entered into an amendment to the Northbridge Lease, effective September 30, 2024. Pursuant to the amendment, the Company's obligation to pay base rent will begin March 1, 2025.
Increase in lease liabilities		$ 17.7
Increase in right-of-use assets		$ 17.9
Massachusetts [Member] | New Premises [Member]
Disclosure Of Leases [Line Items]
Original lease term	15 years 4 months
Lease existence of option to extend	true
Lease option to extend	The lease includes a non-cancellable lease term of fifteen years and four months, with two options to extend the lease term for two additional terms of either five years or ten years at 95% of the then-prevailing fair market rent.
Number of renewal options | Tranche	2
Lease renewal rate at 95% of market rent at time of renewal	95.00%
Area of property covered | ft²	41,141
Massachusetts [Member] | Minimum [Member] | New Premises [Member]
Disclosure Of Leases [Line Items]
Additional lease renewal option period	5 years
Massachusetts [Member] | Maximum [Member] | New Premises [Member]
Disclosure Of Leases [Line Items]
Additional lease renewal option period	10 years