Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Loss Carryforwards [Line Items]
Percentage of Net Operating Losses Limited upon Tax Reform Enactment		80.00%
Deferred tax asset related to state net operating loss carry-forwards		$ 1,586,000	$ 893,000
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		35.00%	35.00%
Federal
Operating Loss Carryforwards [Line Items]
Federal net operating losses for income tax			$ 14,000,000
State
Operating Loss Carryforwards [Line Items]
Federal net operating losses for income tax		$ 34,200,000	$ 19,600,000
Federal tax reform [Member]
Operating Loss Carryforwards [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%