Income Taxes - Additional Information (Detail) (USD $)					12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 eProsper	Dec. 31, 2010 eProsper	Dec. 31, 2011 Internal Revenue Service (IRS)	Dec. 31, 2011 State and Local Jurisdiction	Dec. 31, 2011 Federal
Income Taxes [Line Items]
Tax years open to examination					Our U.S. federal tax returns for 2006 and subsequent years remain open to examination.	Our California and Massachusetts tax returns for the years 2006 and 2007, respectively, and subsequent years remain open to examination.
Tax years under examination					The Company is currently under audit examination by the IRS for the 2008 and 2009 tax years, which began in July 2011.
Current taxes receivable	$ 1,000,000	$ 200,000
Federal net operating loss carryforwards	15,800,000	10,400,000
State net operating loss carryforward	7,800,000	5,200,000
Federal and state net operating loss carryforwards subject to limitations						2,200,000	7,200,000
Valuation allowance related to operating loss carryforward and research and development credits			6,500,000	4,200,000
Unrecognized tax benefit	780,000	430,000
Reduction in income tax expense resulting from recognition of unrecognized tax benefit	$ 600,000