Commitments and Contingencies - Schedule of Future Minimum Lease Payments under Non-cancellable Operating Leases, Reconciliation of Undiscounted Cash Flows to the Operating Lease Liability (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Operating Lease Liabilities, Payments Due [Abstract]
2021 (Excluding the six months ended June 30, 2021)	$ 967
2022	1,957
2023	1,992
Total future minimum lease payments, undiscounted	4,916
Less imputed interest	(421)
Operating lease liabilities	4,495
Operating lease liabilities reported as of December 31, 2020:
Operating lease liabilities - current	1,677	$ 1,602
Operating lease liabilities - non-current	2,818	$ 3,673
Total	$ 4,495