Condensed Consolidated Statements of Cash Flows (unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Cash flows from operating activities:
Net loss	$ (6,611)	$ (10,532)
Depreciation and amortization of property and equipment	2,166	1,912
Amortization of acquired intangible assets	2,508	898
Stock-based compensation expense	2,709	1,087
Loss on asset disposition		174
Accounts receivable	52	(567)
Prepaid expenses and other current assets	570	(231)
Accounts payable	(2)	(155)
Accrued compensation and benefits	723	711
Accrued expenses and other current liabilities	(1,043)	(268)
Deferred rent	(230)	(184)
Deferred revenue	12	329
Net cash provided by(used in) operating activities	854	(6,826)
Cash flows from investing activities:
Purchases of short-term investments	(18,102)	(20,329)
Maturities of short-term investments	17,958	26,404
Purchases of property and equipment	(2,846)	(1,875)
Net cash used in investing activities	(2,990)	(6,456)
Cash flows from financing activities:
Value of equity awards withheld for tax liability and award exercises	(428)	(235)
Proceeds from exercises of stock options	1,687	14
Net cash provided by (used in) financing activities	1,259	(221)
Net decrease in cash and cash equivalents	(877)	(13,503)
Cash and cash equivalents at beginning of period	7,958	16,687
Cash and cash equivalents at end of period	7,081	3,184
RealEstate.com [Member]
Cash flows from investing activities:
Cash paid for acquisition		(8,250)
SharperAgent [Member]
Cash flows from investing activities:
Cash paid for acquisition		(1,656)
kwkly [Member]
Cash flows from investing activities:
Cash paid for acquisition		$ (750)