Accounts Receivable - Schedule of Accounts Receivable (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Receivables [Abstract]
Accounts receivable	$ 86,167	$ 63,116
Notes receivable	7,425	281
Allowances for doubtful accounts	(94)	(83)	$ (236)	$ (263)
Sales return reserves	(628)	(1,107)	(1,481)	(787)
Low yield compensation reserve	(844)	(432)	$ (480)	$ (1,100)
Accounts receivable, net	$ 92,026	$ 61,775