Revenues and Accounts Receivable - Schedule of Accounts Receivable, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues And Accounts Receivable [Abstract]
Accounts receivable, invoiced	$ 57,228	$ 46,643
Accounts receivable, other	1,139	611
Allowance for doubtful accounts	(4,265)	(1,327)	$ (453)
Accounts receivable—net	$ 54,102	$ 45,927