Restricted Cash - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	May 31, 2019	Dec. 31, 2018
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash in current assets			$ 361
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	Nov. 30, 2023
Restricted cash in current assets			361
Restricted cash balance	$ 408		$ 408