Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Statement [Abstract]
Revenue	$ 72,951	$ 68,975	$ 143,674	$ 135,281
Cost of revenue	19,733	19,332	39,606	37,885
Gross profit	53,218	49,643	104,068	97,396
Operating expenses:
Sales and marketing	32,986	32,198	63,339	62,170
General and administrative	17,253	18,605	35,181	36,754
Product development	7,380	6,215	13,970	12,248
Total operating expenses	57,619	57,018	112,490	111,172
Loss from operations	(4,401)	(7,375)	(8,422)	(13,776)
Interest expense	1,133	1,069	2,250	2,199
Amortization of debt issuance costs	143	143	286	286
Other expense (income), net	1,655	(658)	1,112	838
Net loss before income tax	(7,332)	(7,929)	(12,070)	(17,099)
Income tax expense	639	562	774	744
Net loss before income tax	$ (7,971)	$ (8,491)	$ (12,844)	$ (17,843)
Net loss per common share:
Basic (in dollars per share)	$ (0.14)	$ (0.15)	$ (0.22)	$ (0.31)
Diluted (in dollars per share)	$ (0.14)	$ (0.15)	$ (0.22)	$ (0.31)
Weighted average number of shares:
Basic (in shares)	57,141,105	56,862,896	57,499,081	56,728,439
Diluted (in shares)	57,141,105	56,862,896	57,499,081	56,728,439