Significant Accounting Policies - Summary of Cumulative Effect of Adoption on Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounts receivable, net	$ 43,673
Inventories, net	47,370		$ 36,499
Total assets	221,068		165,724	$ 154,067
Income taxes payable	710		300
Deferred revenue	5,069		5,791
Sales allowances	548
Total liabilities	36,978		29,305
Retained earnings	129,000		93,605
Total equity	184,090		136,419	$ 131,017	$ 136,085
Total liabilities and equity	221,068		$ 165,724
Accounting Standards Update 2014-09 [Member]
Sales allowances	(548)
Accounting Standards Update 2014-09 [Member] | Adjustments [Member]
Accounts receivable, net	(72)
Inventories, net	(110)
Total assets	(182)
Income taxes payable	(59)
Deferred revenue	5,768
Sales allowances	(483)
Total liabilities	5,226
Retained earnings	(5,408)	$ 3,670
Total equity	(5,408)
Total liabilities and equity	(182)
Accounting Standards Update 2014-09 [Member] | Balances without adoption of Topic 606 [Member]
Accounts receivable, net	43,601
Inventories, net	47,260
Total assets	220,886
Income taxes payable	651
Deferred revenue	10,837
Sales allowances	65
Total liabilities	42,204
Retained earnings	123,592
Total equity	178,682
Total liabilities and equity	$ 220,886