Income Taxes - Schedule of Significant Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Deferred tax assets, Accounts receivable	$ 380	$ 535
Deferred tax assets, Inventories	73	194
Deferred tax assets, Deferred revenue	230	279
Deferred tax assets, Accrued expenses and reserves	5,942	2,642
Deferred tax assets, Stock-based compensation	1,061	1,034
Deferred tax assets, Tax credits and loss carryforwards	3,763	4,053
Deferred tax assets, Other	16	6
Total gross deferred tax assets	11,465	8,743
Less: Valuation allowance	(2,981)	(2,274)
Total deferred tax assets	8,484	6,469
Deferred tax liabilities, Property and equipment	(5,192)	(4,154)
Deferred tax liabilities, Intangibles	(2,582)	(1,659)
Deferred tax liabilities, Foreign employment tax subsidy		(517)
Deferred tax liabilities, Prepaid expenses	(648)	(944)
Deferred tax liabilities, Other	(474)	(538)
Total deferred tax liabilities	(8,896)	(7,812)
Net deferred tax liabilities	$ (412)	$ (1,343)