Summary of Significant Accounting Policies- Summary of net unrealized gains and losses for the period that relate to marketable securities (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Marketable Securities, Gain (Loss) [Abstract]
Net losses recognized during the period on equity securities	$ (3,749)	$ (92)	$ (9,774)	$ (106)
Less: Net gains and losses recognized during the period on equity securities sold during the period	0	42	0	1
Unrealized losses recognized during the period on equity securities held	$ (3,749)	$ (134)	$ (9,774)	$ (107)