Contractual Payment Obligation - Additional Information (Detail) - USD ($)		3 Months Ended		9 Months Ended
	Apr. 13, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Related Party Transaction [Line Items]
Interest accreted on payment obligation		$ 28,000	$ 33,000	$ 115,000	$ 115,000
Settlement Agreement
Related Party Transaction [Line Items]
Amended installment payment, contractual payment period	Oct. 31, 2021
Increase in contractual payment obligation	$ 90,000
Settlement Agreement | Maximum
Related Party Transaction [Line Items]
Installment payment, contractual payment year				2021