Revenues - Summary of Changes in Certain Contract Assets and Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Accounts receivable	$ 48,502	$ 38,115
Short-term deferred revenue and customer prepayments	(7,817)	(5,507)
Long-term deferred revenue	(894)	(1,054)
Deferred expenses	1,552	1,897
Sales allowances	(867)	$ (741)
Accounting Standards Update 2014-09 [Member]
Disaggregation of Revenue [Line Items]
Accounts receivable	10,387
Short-term deferred revenue and customer prepayments	(2,310)
Long-term deferred revenue	160
Deferred expenses	(345)
Sales allowances	$ (126)