Financial Instruments - Carrying Value and Estimated Fair Value of Financial Instruments (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Carrying Amount
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 65,075	$ 63,255
Accounts receivable, net	12,277	11,870
Accounts payable	2,693	2,514
Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash and cash equivalents	65,075	63,255
Accounts receivable, net	12,277	11,870
Accounts payable	$ 2,693	$ 2,514