Business Segments - Financial Performance by Segment and Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Revenue:
Total revenue	$ 28,565	$ 24,435	$ 55,803	$ 51,404
Segment Operating Expenses:
Consolidated operating expenses	32,517	30,728	64,460	62,927
Segment operating contribution and Reconciliation to consolidated pre-tax income (loss):
Adjusted EBITDA	(3,933)	(5,171)	(8,358)	(10,226)
Add (deduct)
Interest income (expense), net	38	23	79	25
Other (expense) income, net	(6)	38,182	(3)	39,162
Depreciation and amortization	(2,799)	(4,857)	(6,066)	(10,588)
Stock-based compensation expense	(2,166)	(2,519)	(4,244)	(4,438)
Acquisition, disposition and realignment costs	(19)	(1,122)	(299)	(1,297)
(Loss) income before income taxes	(8,885)	24,536	(18,891)	12,638
Corporate
Segment Operating Expenses:
Consolidated operating expenses	6,607	6,832	13,522	14,264
Segment operating contribution and Reconciliation to consolidated pre-tax income (loss):
Adjusted EBITDA	(6,607)	(6,832)	(13,522)	(14,264)
Acquisition, disposition and realignment costs
Segment operating contribution and Reconciliation to consolidated pre-tax income (loss):
Adjusted EBITDA	19	1,122	299	1,297
Marketplaces
Segment Revenue:
Total revenue	17,691	13,409	33,568	26,871
Marketplaces | Operating Segments
Segment Operating Expenses:
Consolidated operating expenses	19,434	13,611	36,716	26,934
Segment operating contribution and Reconciliation to consolidated pre-tax income (loss):
Adjusted EBITDA	(1,743)	(202)	(3,148)	(63)
Media
Segment Revenue:
Total revenue	10,874	11,026	22,235	24,533
Media | Operating Segments
Segment Operating Expenses:
Consolidated operating expenses	6,476	10,285	14,222	21,729
Segment operating contribution and Reconciliation to consolidated pre-tax income (loss):
Adjusted EBITDA	$ 4,398	$ 741	$ 8,013	$ 2,804