Business Segments - Financial Performance by Segment and Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Revenue:
Total revenue	$ 128,990	$ 113,452	$ 125,969
Segment Operating Expenses:
Consolidated operating expenses	139,963	129,868	135,294
Segment operating contribution and Reconciliation to consolidated pre-tax income (loss):
Adjusted EBITDA	(10,674)	(15,020)	(6,837)
Add (deduct)
Interest income (expense), net	190	92	218
Other (expense) income, net	(19)	40,172	3,107
Depreciation and amortization	(11,803)	(18,090)	(29,884)
Stock-based compensation expense	(8,565)	(7,779)	(7,562)
Acquisition, disposition and realignment costs	(299)	(1,396)	(2,488)
Loss before income taxes	(31,170)	(2,021)	(43,446)
Corporate
Segment Operating Expenses:
Consolidated operating expenses	26,691	27,845	31,424
Segment operating contribution and Reconciliation to consolidated pre-tax income (loss):
Adjusted EBITDA	(26,691)	(27,845)	(31,424)
Acquisition, disposition and realignment costs
Segment operating contribution and Reconciliation to consolidated pre-tax income (loss):
Adjusted EBITDA	299	1,396	2,488
Marketplaces
Segment Revenue:
Total revenue	84,126	66,139	52,155
Marketplaces | Operating Segments
Segment Operating Expenses:
Consolidated operating expenses	86,656	65,513	50,294
Segment operating contribution and Reconciliation to consolidated pre-tax income (loss):
Adjusted EBITDA	(2,530)	626	1,861
Media
Segment Revenue:
Total revenue	44,864	47,313	73,814
Media | Operating Segments
Segment Operating Expenses:
Consolidated operating expenses	26,616	36,510	53,576
Segment operating contribution and Reconciliation to consolidated pre-tax income (loss):
Adjusted EBITDA	$ 18,248	$ 10,803	$ 20,238