Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Revenue	$ 13,478	$ 12,715	$ 35,509	$ 28,788
Cost of revenue	1,868	764	4,032	2,445
Gross profit	11,610	11,951	31,477	26,343
Operating expenses:
Technology and development	2,432	2,116	7,044	6,650
Sales and marketing	5,840	7,461	18,778	21,687
General and administrative	4,306	5,343	14,670	14,990
Restructuring costs	32	0	149	0
Depreciation and amortization	523	984	3,198	2,995
Mark-to-market	0	0	0	148
Total operating expenses	13,133	15,904	43,839	46,470
Loss from continuing operations	(1,523)	(3,953)	(12,362)	(20,127)
Interest and other income (expense), net:
Interest expense	(27)	(11)	(74)	(78)
Other income, net	72	662	1,917	624
Total interest and other income, net	45	651	1,843	546
Loss from continuing operations before income taxes	(1,478)	(3,302)	(10,519)	(19,581)
Provision (benefit) for income taxes	103	(29)	146	56
Loss from continuing operations, net of income taxes	(1,581)	(3,273)	(10,665)	(19,637)
Gain (loss) on sale of discontinued operations, net of income taxes	0	14,924	(136)	14,924
Income from discontinued operations, net of income taxes	0	643	0	7,847
Total income (loss) from discontinued operations, net of income taxes	0	15,567	(136)	22,771
Net income (loss)	$ (1,581)	$ 12,294	$ (10,801)	$ 3,134
Net income (loss) per share — basic and diluted:
Loss from continuing operations, net of income taxes (usd per share)	$ (0.03)	$ (0.06)	$ (0.21)	$ (0.39)
Income from discontinued operations, net of income taxes (usd per share)	0.00	0.30	0.00	0.45
Net income (loss) (usd per share)	$ (0.03)	$ 0.24	$ (0.21)	$ 0.06
Weighted-average number of shares of common stock outstanding:
Basic and diluted (shares)	52,716,626	50,642,344	52,265,228	50,280,849