Commitments and Contingencies - Summary of Reconciliation of Company’s Undiscounted Payments for Facility Lease and Carrying Amount of Lease Liability (Detail) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Operating Lease Liabilities, Payments Due [Abstract]
2019	$ 82,000
2020	335,000
2021	345,000
2022	355,000
2023	364,000
Thereafter	280,000
Remaining Facility Lease Payments	1,761,000
Less: Discount Adjustment	(231,000)
Total lease liability	1,530,000
Lease liability - current portion	253,079	$ 59,579
Long-term lease liability	$ 1,276,685	$ 476,753