Discontinued Operations - Results from Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2016	[1]	Sep. 30, 2016	[1]	Jun. 30, 2016	[1]	Mar. 31, 2016	[1]	Dec. 31, 2015	[1]	Sep. 30, 2015	[1]	Jun. 30, 2015	[1]	Mar. 31, 2015	[1]	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Other income (expense):
Income tax provision																	$ 6,500
Loss from discontinued operations, net of applicable taxes	$ 5,727		$ (3,658)		$ (3,324)		$ (2,369)		$ (3,440)		$ (3,267)		$ 243		$ (963)		(3,624)	$ (7,423)	$ (12,784)
International operations | Discontinued operations, disposed of by sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues																	40,130	50,891	52,355
Cost of revenues																	19,381	17,376	16,826
Amortization of acquired intangible assets																	1,291	1,453	1,787
Gross profit																	19,458	32,062	33,742
Operating (income) expenses:
Research and development																	51	152	206
Sales and marketing																	12,980	19,055	21,397
General and administrative																	4,846	6,741	11,075
Amortization of intangible assets																	622	1,200	0
Goodwill and intangible impairment																	0	908	0
Restructuring expenses																	794	591	706
Net gain on sale of business																	(7,935)	0	0
Total operating expenses																	11,358	28,647	33,384
Operating income																	8,100	3,415	358
Other income (expense):
Interest income																	45	42	0
Interest expense																	(7,004)	(8,588)	(10,594)
Other income (expense), net																	1,883	(466)	(1,869)
Total other income (expense)																	(5,076)	(9,012)	(12,463)
Income (loss) from discontinued operations before taxes																	3,024	(5,597)	(12,105)
Income tax provision																	6,648	1,826	679
Loss from discontinued operations, net of applicable taxes																	$ (3,624)	$ (7,423)	$ (12,784)

[1] Selected quarterly financial data for periods prior to the nine months ended September 30, 2016 have been recast to reflect discontinued operations.