Commitments and Contingencies - Information related to Right-of-use Assets and Liabilities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Cash paid for operating lease liabilities	$ 489	$ 797
Right-of-use assets obtained in exchange for new operating lease obligations	$ 1,976	$ 803
Weighted-average remaining lease term	4 years 9 months 18 days	7 months 6 days
Weighted-average discount rate	12.30%	12.80%