Income Taxes - Summary of Gross Unrecognized Tax Benefits (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Reconciliation Of Unrecognized Tax Benefits Excluding Amounts Pertaining To Examined Tax Returns [Abstract]
Balance at January 1,	$ 1,738,815	$ 1,738,815
Current Year Uncertain Tax Positions:
Gross Increases	0	0
Balance at December 31,	$ 1,738,815	$ 1,738,815