Significant Accounting Policies - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2019 USD ($)
Significant Accounting Policies [Line Items]
Right-of-use asset	$ 2,133,000
Lease liability	2,133,000
ASU 2016-02 [Member]
Significant Accounting Policies [Line Items]
Change in accounting principle for adoption of ASU 2016-01	0
Other Assets [Member]
Significant Accounting Policies [Line Items]
Right-of-use asset	2,210,000
Accrued Expenses {Member]
Significant Accounting Policies [Line Items]
Lease liability	$ 2,210,000