Revenue Recognition and Reserve for Sales Returns and Allowances - Additional Information (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Significant Accounting Policies [Line Items]
Reserve for sales returns and allowances	$ 38,109	$ 29,403
Minimum
Significant Accounting Policies [Line Items]
Discount on invoiced amount of products	1.00%
Maximum
Significant Accounting Policies [Line Items]
Discount on invoiced amount of products	20.00%