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Restructuring - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	Feb. 28, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Restructuring Cost And Reserve [Line Items]
Percent of reduction in headcount of employees	30.00%
Restructuring Charges		$ 0		$ 0	$ 1,492,000
Cash payments			$ 206,000		1,101,000
Remaining unpaid liabilities related to restructuring charges		$ 0		$ 0
Severance And Other Termination Benefits [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring Charges					$ 1,492,000