Commitments and Contingencies - Summary of Restructuring Activity (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Aug. 07, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Restructuring Cost And Reserve [Line Items]
Beginning balance				$ 45
Restructuring expenses	$ 600	$ 25	$ 295	124	$ 295
Payments made				(242)
Payments received				77
Ending balance		4		4
Severance [Member]
Restructuring Cost And Reserve [Line Items]
Beginning balance				12
Restructuring expenses				124
Payments made				(136)
Payments received				0
Ending balance		0		0
Lease Termination [Member]
Restructuring Cost And Reserve [Line Items]
Beginning balance				33
Restructuring expenses				0
Payments made				(106)
Payments received				77
Ending balance		$ 4		$ 4