Leases - Components of Lease Cost (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Leases [Abstract]
Operating lease costs	$ 538	$ 673
Short-term lease costs	77	71
Variable lease costs	2	19
Amortization of finance lease assets	59	78
Interest on finance lease liabilities	6	6
Total lease cost	$ 682	$ 847