Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Revenues	$ 56,150	$ 49,284	$ 162,366	$ 142,234
Cost of revenues	18,645	16,171	54,166	47,024
Gross profit	37,505	33,113	108,200	95,210
Operating expenses
Sales and marketing	18,239	16,526	54,059	49,092
Research and development	6,549	5,574	17,023	16,185
General and administrative	8,744	7,149	24,709	21,516
Amortization of intangible assets	1,128	1,194	3,460	3,553
Total operating expenses	34,660	30,443	99,251	90,346
Income from operations	2,845	2,670	8,949	4,864
Other income (expense)
Interest income, net	272	112	704	408
Other income (expense), net	(195)	947	(356)	866
Total other income (expense), net	77	1,059	348	1,274
Income before income taxes	2,922	3,729	9,297	6,138
Income tax expense	(1,058)	(1,220)	(2,636)	(2,233)
Net income	$ 1,864	$ 2,509	$ 6,661	$ 3,905
Net income per share
Basic	$ 0.11	$ 0.15	$ 0.39	$ 0.23
Diluted	$ 0.11	$ 0.14	$ 0.38	$ 0.23
Weighted average common shares used to compute net income per share
Basic	17,223	17,001	17,192	16,916
Diluted	17,410	17,341	17,394	17,185
Other comprehensive income (loss)
Foreign currency translation adjustments	$ 1,779	$ 443	$ 4,291	$ 2,408
Unrealized gain (loss) on investments (net of tax of $10, ($50), $0, $12)	17	(80)		20
Reclassification of unrealized gain on investments into earnings (net of tax of $44, $14, $29, $13)	72	22	48	21
Comprehensive income	$ 3,732	$ 2,894	$ 11,000	$ 6,354