Ownership Interests and Cost Method Companies - Additional Information (Detail) (USD $)	3 Months Ended				6 Months Ended							3 Months Ended		6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012		Dec. 31, 2012	Dec. 31, 2012 Marketable securities	Dec. 31, 2012 Prepaid Expenses and Other Current Assets	Jun. 30, 2013 Active	Jun. 30, 2012 Active	Jun. 30, 2013 Active	Jun. 30, 2012 Active	Jun. 30, 2013 Anthem	Jun. 30, 2012 Bolt	Dec. 31, 2011 Bolt
Schedule Of Equity Method Investments [Line Items]
Net asset of equity method	$ 17,300,000				$ 17,300,000				$ 15,300,000
Net asset allocated of equity method goodwill	15,100,000				15,100,000				12,000,000
Allocated of equity method intangible	2,200,000				2,200,000				3,300,000
Amortized period					5 years		5 years
Amortization of intangible assets	(48,000)	[1]	(327,000)	[2]	(69,000)	[3]	(592,000)	[2]
Acquired preferred stock																	9,000,000
Equity method investment, ownership percentage																9.00%	38.00%	26.00%
Fair value of active common stock remaining									700,000	300,000	400,000
Sale of common stock, shares												150,233	447,057	150,233	447,057
Common stock price per share												$ 5.10	$ 16.88	$ 5.10	$ 16.88
Proceeds from sales of marketable securities					760,000		7,526,000					800,000	7,500,000
Gain on sale of securities												100,000	100,000	1,400,000	1,400,000
Carrying value of holdings in cost method companies	$ 15,000,000				$ 15,000,000				$ 13,000,000

[1] Includes Acquirgy, CIML, Freeborders and WhiteFence.

[2] Includes Acquirgy, Bolt, CIML, Freeborders, GoIndustry-DoveBid plc (“GoIndustry”) and WhiteFence.

[3] Includes Acquirgy, CIML (from February 20, 2013, the date of deconsolidation), Freeborders and WhiteFence.