Leases - Schedule of Components of Lease Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Leases [Abstract]
Fixed operating lease cost	$ 413	$ 225	$ 847	$ 610
Short-term lease costs	40	38	116	84
Total lease expense	453	263	963	694
Right-of-use asset obtained in exchange for operating lease liabilities	4,646
Operating cash flows from operating leases	479	268	963	737
Sublease income	$ 49	$ 0	$ 146	$ 0
Weighted-average remaining lease term-operating leases (in years)	5 years 9 months 18 days		5 years 9 months 18 days
Weighted-average discount rate-operating leases	11.20%		11.20%