Leases - Schedule of Components of Lease Expense and Related Cash Flows (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Leases [Abstract]
Operating lease cost	$ 91	$ 51	$ 209	$ 152
Short-term lease cost	7	7	20	36
Total Lease Cost	98	58	229	188
Operating cash flows used for operating leases	$ 60	$ 53	$ 175	$ 157