Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Revenue	$ 18,216	$ 12,430	$ 31,838	$ 22,031
Cost of revenue	3,468	1,136	5,919	2,164
Gross profit	14,748	11,294	25,919	19,867
Operating expenses:
Technology and development	2,739	2,305	5,594	4,613
Sales and marketing	6,756	6,646	13,103	12,938
General and administrative	7,528	5,365	14,365	10,363
Restructuring costs	0	117	0	117
Depreciation and amortization	370	874	809	2,675
Total operating expenses	17,393	15,307	33,871	30,706
Loss from continuing operations	(2,645)	(4,013)	(7,952)	(10,839)
Interest and other income (expense), net:
Interest income (expense)	2	(45)	(1)	(48)
Other income, net	1,203	1,127	2,187	1,844
Total interest income (expense) and other income, net	1,205	1,082	2,186	1,796
Loss from continuing operations before income taxes	(1,440)	(2,931)	(5,766)	(9,043)
Provision for income taxes	44	29	51	43
Loss from continuing operations, net of income taxes	(1,484)	(2,960)	(5,817)	(9,086)
Loss on sale of discontinued operations, net of income taxes	0	(161)	0	(136)
Net loss	$ (1,484)	$ (3,121)	$ (5,817)	$ (9,222)
Net loss per share — basic and diluted:
Loss from continuing operations, net of income taxes (usd per share)	$ (0.03)	$ (0.06)	$ (0.13)	$ (0.18)
Loss from discontinued operations, net of income taxes (usd per share)	0.00	0.00	0.00	0.00
Net loss (usd per share)	$ (0.03)	$ (0.06)	$ (0.13)	$ (0.18)
Weighted-average number of shares of common stock outstanding:
Basic and diluted (shares)	45,702,810	52,241,605	45,283,647	52,035,788