CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Income Statement [Abstract]
Revenue	$ 34,610	$ 30,592
Operating expenses
Cost of revenue	10,192	9,732
Sales and marketing	13,159	11,236
General and administrative	14,496	15,436
Research and development	7,550	7,093
Amortization of intangibles assets	4,064	4,016
Impairment related and other	231	346
Total operating expenses	49,692	47,859
Operating loss	(15,082)	(17,267)
Other (loss) income, net	(156)	1,537
Interest income	48	19
Interest expense	(46)	(37)
Loss before income taxes and noncontrolling interest	(15,236)	(15,748)
Income tax expense	(147)	(177)
Net loss	(15,383)	(15,925)
Less: Net loss attributable to the noncontrolling interest	(1,052)	(1,160)
Net loss attributable to Actua Corporation	$ (14,331)	$ (14,765)
Basic and diluted net loss per share attributable to Actua Corporation: (in dollars per share)	$ (0.38)	$ (0.40)
Shares used in computation of basic and diluted loss per share (in shares)	37,293	36,842
Net loss	$ (15,383)	$ (15,925)
Other comprehensive loss:
Foreign currency translation adjustment	(74)	0
Comprehensive loss	(15,457)	(15,925)
Less: Comprehensive loss attributable to the noncontrolling interest	(1,052)	(1,160)
Comprehensive loss attributable to Actua Corporation	$ (14,405)	$ (14,765)