Stockholders' Equity - Additional Information (Detail) - Common Stock Class Two [Member] - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Class Of Stock [Line Items]
Common stock issued, Shares	6,254,980
Proceeds from issuance of common stock, gross	$ 159,213,000	$ 27,579,000
Transaction costs recorded net against allocated gross proceeds in additional paid-in-capital	3,184,000
Maximum allowed aggregate gross proceeds from share issuance under ATM program	20,000,000
Maximum amount of share issuance allowed per quarter	$ 6,000,000