CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenue	$ 84,837	$ 59,201	$ 26,640
Operating expenses
Cost of Revenue	24,420	17,757	9,459
Sales and marketing	39,710	28,129	12,355
General and administrative	51,731	30,960	28,408
Research and development	15,408	9,032	8,807
Amortization of intangibles assets	10,532	8,470	4,837
Impairment related and other	1,187	4,292	1,130
Total operating expenses	142,988	98,640	64,996
Operating loss	(58,151)	(39,439)	(38,356)
Other income (loss), net	5,300	(4,210)	57,820
Interest income	463	227	439
Interest expense	(1,613)	(1,484)	(25)
Income (loss) before income taxes, equity loss and noncontrolling interest	(54,001)	(44,906)	19,878
Income tax benefit (expense)	12,931	17,571	(1,336)
Equity loss	(776)	(2,963)	(8,672)
Income (loss) from continuing operations	(41,846)	(30,298)	11,098
Income from discontinued operations, including gain on sale, net of tax	14,026	232,339	12,483
Net income (loss)	(27,820)	202,041	23,581
Less: Net income (loss) attributable to the noncontrolling interest	(4,264)	(7,018)	592
Net income (loss) attributable to Actua Corporation	(23,556)	209,059	22,989
Amounts attributable to Actua Corporation:
Net income (loss) from continuing operations	(37,582)	(25,669)	12,703
Net income from discontinued operations	14,026	234,728	10,286
Net income (loss) attributable to Actua Corporation	(23,556)	209,059	22,989
Basic income (loss) per share attributable to Actua Corporation:
Income (loss) from continuing operations	$ (1.01)	$ (0.70)	$ 0.35
Income from discontinued operations	$ 0.38	$ 6.42	$ 0.29
Net income (loss)	$ (0.63)	$ 5.72	$ 0.64
Shares used in computation of basic income (loss) per share	37,130	36,536	35,890
Diluted income (loss) per share attributable to Actua Corporation:
Income (loss) from continuing operations	$ (1.01)	$ (0.70)	$ 0.35
Income from discontinued operations	$ 0.38	$ 6.42	$ 0.28
Net income (loss)	$ (0.63)	$ 5.72	$ 0.63
Shares used in computation of diluted income (loss) per share	37,130	36,536	36,543
Net income (loss)	(27,820)	202,041	23,581
Other comprehensive income
Unrealized holding gain in marketable securities		24	1,552
Reclassified adjustments/realized net (gains) loss on marketable securities	(269)	(23)	(1,552)
Other accumulated other comprehensive loss		(1)	(34)
Comprehensive income (loss)	(27,820)	202,041	23,547
Less: Comprehensive income (loss) attributable to noncontrolling interests	(4,264)	(7,018)	558
Comprehensive income (loss) attributable to Actua Corporation	(23,556)	209,059	22,989
Continuing Operations
Operating expenses
Income tax benefit (expense)			$ (108)