Commitments and Contingencies - Summary of Reconciliation of Company’s Undiscounted Payments for Facility Lease and Carrying Amount of Lease Liability (Detail) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Operating Lease Liabilities, Payments Due [Abstract]
Remaining Facility Lease Payments	$ 1,925,000
Less: Discount Adjustment	(277,000)
Total lease liability	1,648,000
Lease liability - current portion	241,144	$ 59,579
Long-term lease liability	$ 1,407,054	$ 476,753