Segments and Geographic Information - Schedule of Other Information by Segment (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Revenues
Product revenues	$ 6,325	$ 5,585
Service revenues	3,253	2,460
Royalties	899	991
Total revenues	10,477	9,036
Cost of product revenues	4,027	3,112
Cost of service revenues	2,323	1,766
Total cost of revenues	6,350	4,878
Gross profit	4,127	4,158
Total operating expenses	5,865	4,279
Total non-operating income	99	144
(Loss) income before income taxes	(1,639)	23
Product [Member]
Revenues
Product revenues	6,325	5,585
Royalties	899	991
Total revenues	7,224	6,576
Cost of product revenues	4,027	3,112
Total cost of revenues	4,027	3,112
Gross profit	3,197	3,464
Service [Member]
Revenues
Service revenues	3,253	2,460
Total revenues	3,253	2,460
Cost of service revenues	2,323	1,766
Total cost of revenues	2,323	1,766
Gross profit	$ 930	$ 694