Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Revenues	$ 29,262	$ 30,440	$ 34,046	$ 34,804	$ 32,051	$ 33,728	$ 36,792	$ 39,145	$ 128,552	$ 141,716	$ 153,240
Cost of revenues	3,331	3,361	3,612	4,009	4,328	4,742	5,208	4,546	14,313	18,824	19,174
Gross profit	25,931	27,079	30,434	30,795	27,723	28,986	31,584	34,599	114,239	122,892	134,066
Operating expenses:
Sales and marketing	15,751	17,184	19,135	18,959	17,161	19,089	20,715	22,077	71,029	79,042	83,511
Product development	2,164	2,317	2,089	2,875	3,316	2,917	3,206	3,089	9,445	12,528	11,326
General and administrative	6,077	5,373	5,434	5,813	6,270	6,120	5,335	6,451	22,697	24,176	29,002
Unexchanged promotional shares									0	0	(7,583)
Total operating expenses	23,992	24,874	26,658	27,647	26,747	28,126	29,256	31,617	103,171	115,746	116,256
Income from operations	1,939	2,205	3,776	3,148	976	860	2,328	2,982	11,068	7,146	17,810
Other income (loss), net	(480)	251	(91)	133	(376)	(202)	(218)	(446)	(187)	(1,242)	91
Income before income tax	1,459	2,456	3,685	3,281	600	658	2,110	2,536	10,881	5,904	17,901
Income tax expense (benefit)	516	837	1,665	1,232	165	(8,199)	1,268	1,806	4,250	(4,960)	4,839
Net income	$ 943	$ 1,619	$ 2,020	$ 2,049	$ 435	$ 8,857	$ 842	$ 730	$ 6,631	$ 10,864	$ 13,062
Basic net income per share (in dollars per share)	$ 0.07	$ 0.12	$ 0.14	$ 0.14	$ 0.03	$ 0.60	$ 0.06	$ 0.05	$ 0.47	$ 0.74	$ 0.88
Diluted net income per share (in dollars per share)	$ 0.07	$ 0.12	$ 0.14	$ 0.14	$ 0.03	$ 0.60	$ 0.06	$ 0.05	$ 0.47	$ 0.74	$ 0.88
Shares used in computing basic net income per share (in shares)									13,997	14,722	14,768
Shares used in computing diluted net income per share (in shares)									13,997	14,722	14,809