Restructuring Activities - Additional Information (Detail) - USD ($)	3 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Restructuring Cost And Reserve [Line Items]
Accrued restructuring expenses		$ 46,000	$ 209,000	$ 66,000	$ 921,000
Restructuring expenses		0	347,000
Payments for restructuring		20,000	1,059,000
Maximum [Member]
Restructuring Cost And Reserve [Line Items]
Payments for restructuring		$ 100,000
Scenario Forecast [Member] | Maximum [Member]
Restructuring Cost And Reserve [Line Items]
Payments for restructuring	$ 100,000
One-time Termination Benefits [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring expenses			300,000
One-time Termination Benefits [Member] | Research and Development Expense [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring expenses			200,000
One-time Termination Benefits [Member] | General and Administrative Expense [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring expenses			$ 100,000
November 2018 Corporate Restructuring [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring activity, announcement date		Nov. 07, 2018