Restricted Cash - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	May 31, 2019
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash balance	$ 408	$ 408
Stamford Lease [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Letter of credit, remaining amount	$ 408		$ 769
Letter of credit, remaining amount date	2019-05
Operating lease, expiration date	Dec. 31, 2023
Restricted cash balance	$ 408	$ 408