Consolidated Statements of Income and Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Product revenue	$ 74,970	$ 74,617
Service revenue	9,489	0
Total revenue	84,459	74,617
Product cost of goods sold	34,832	29,738
Service cost of goods sold	3,409	0
Cost of goods sold	38,241
Gross profit	46,218	44,879
Operating expenses:
Selling expenses	21,940	24,804
General and administrative expenses	22,441	19,363
Operating expenses	44,381	44,167
Operating income	1,837	712
Interest expense (benefit)	(240)	(94)
Other income, net	287	225
Income before income taxes	1,884	843
Income tax expense (benefit)	$ 648	$ (14)
Income per share of common stock:
Basic income per share of common stock	$ 0.14	$ 0.10
Diluted income per share of common stock	$ 0.13	$ 0.09
Weighted average shares outstanding:
Basic weighted average shares outstanding	8,888	8,834
Effect of dilutive securities outstanding	297	255
Diluted weighted average shares outstanding	9,185	9,089
Comprehensive income:
Net income	$ 1,236	$ 857
Adjustment for foreign currency translation	(1,483)	73
Net comprehensive income (loss)	$ (247)	$ 930