Components of Net Deferred Income Tax Asset and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Net deferred income tax asset-Current
Warranty cost	$ 657	$ 404
Bad debt reserve	21	30
Inventory reserve	774	512
Unearned service revenue	4,319	3,474
Other, net	2,021	1,516
Net deferred income tax asset-Current	7,792	5,936
Net deferred income tax asset-Non-current
Depreciation	(5,658)	(3,195)
Goodwill amortization	(2,076)	(2,007)
Employee stock options	3,664	2,756
Unearned service revenue	2,337	1,649
Loss carryforwards	6,568	9,240
Deferred income tax asset-Non-current	4,835	8,443
Valuation Allowance	(785)	(1,819)
Net deferred income tax asset-Non-current	4,050	$ 6,624
Net deferred income tax liability-Non-current
Intangible assets	$ (686)