Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Statement [Abstract]
Revenue	$ 12,430	$ 9,934	$ 22,031	$ 16,073
Cost of revenue	1,136	917	2,164	1,681
Gross profit	11,294	9,017	19,867	14,392
Operating expenses:
Technology and development	2,305	2,109	4,613	4,534
Sales and marketing	6,646	7,700	12,938	14,226
General and administrative	5,365	4,774	10,363	9,647
Restructuring costs	117	0	117	0
Depreciation and amortization	874	990	2,675	2,011
Mark-to-market	0	93	0	148
Total operating expenses	15,307	15,666	30,706	30,566
Loss from continuing operations	(4,013)	(6,649)	(10,839)	(16,174)
Interest and other income (expense), net:
Interest expense	(45)	(33)	(48)	(67)
Other income (expense), net	1,127	(45)	1,844	(38)
Total interest and other income (expense), net	1,082	(78)	1,796	(105)
Loss from continuing operations before income taxes	(2,931)	(6,727)	(9,043)	(16,279)
Provision for income taxes	29	89	43	79
Loss from continuing operations, net of income taxes	(2,960)	(6,816)	(9,086)	(16,358)
Loss on sale of discontinued operations, net of income taxes	(161)	0	(136)	0
Income from discontinued operations, net of income taxes	0	4,516	0	7,198
Total income (loss) from discontinued operations, net of income taxes	(161)	4,516	(136)	7,198
Net loss	$ (3,121)	$ (2,300)	$ (9,222)	$ (9,160)
Net income (loss) per share — basic and diluted:
Loss from continuing operations, net of income taxes (usd per share)	$ (0.06)	$ (0.14)	$ (0.18)	$ (0.32)
Income from discontinued operations, net of income taxes (usd per share)	0.00	0.09	0.00	0.14
Net loss (usd per share)	$ (0.06)	$ (0.05)	$ (0.18)	$ (0.18)
Weighted-average number of shares of common stock outstanding:
Basic and diluted (shares)	52,241,605	50,205,913	52,035,788	50,102,803