Basis of Presentation and Significant Accounting Policies - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Accounting Policies [Line Items]
Available-for-sale securities, allowance for credit losses	$ 0	$ 0
Realized gains or losses on the sale of available-for-sale securities	$ 0
ASU 2016-13 [Member]
Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adopted	true
Change in accounting principle, accounting standards update, adoption date	Jan. 01, 2020
Change in accounting principle, accounting standards update, immaterial effect	true
ASU 2018-13 [Member]
Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adopted	true
Change in accounting principle, accounting standards update, adoption date	Jan. 01, 2020
Change in accounting principle, accounting standards update, immaterial effect	true