Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
OPERATING ACTIVITIES:
Net (loss) income	$ (3,499)	$ 6,355	$ 12,038
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Stock-based compensation expense	12,508	10,715	6,771
Depreciation	8,090	7,329	6,563
Amortization of purchased intangibles	2,643	580	1,029
Provision for doubtful accounts, net	457	20	290
Deferred income taxes	(4,877)	(2,871)	229
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable	(4,630)	(664)	(4,798)
Prepaid expenses and other current assets	768	(1,086)	665
Other assets	167	(164)	522
Accounts payable	(2,660)	2,920	1,451
Accrued expenses	6,822	3,654	211
Deferred revenue	1,413	1,258	447
Other liabilities	(244)	(37)	(344)
Net cash provided by operating activities	16,958	28,009	25,074
INVESTING ACTIVITIES:
Purchases of property and equipment, including capitalized software	(8,044)	(11,221)	(7,268)
Acquisition of domains	(51)	0	0
Acquisition of Proficient	0	(77)	(75)
Acquisition of Engage, net of cash acquired	(79)	(8,465)	0
Acquisition of Amadesa technology assets	0	(10,798)	0
Acquisition of LookIO, net of cash acquired	0	(900)	0
Net cash used in investing activities	(8,174)	(31,461)	(7,343)
FINANCING ACTIVITIES:
Repurchase of common stock	(26,715)	0	0
Excess tax benefit from the exercise of employee stock options	193	4,104	4,001
Proceeds from issuance of common stock in connection with the exercise of options	6,313	9,406	10,280
Net cash (used in) provided by financing activities	(20,209)	13,510	14,281
EFFECT OF FOREIGN EXCHNAGE RATE CHANGES ON CASH AND CASH EQUIVALENTS	(8)	3	(70)
CHANGE IN CASH AND CASH EQUIVALENTS	(11,433)	10,061	31,942
CASH AND CASH EQUIVALENTS - Beginning of the year	103,339	93,278
CASH AND CASH EQUIVALENTS - End of the year	91,906	103,339	93,278
SUPPLEMENTAL DISCLOSURE OF OTHER CASH FLOW INFORMATION:
Cash paid for income taxes	1,163	1,556	2,579
SUPPLEMENTAL DISCLOSURE OF NON CASH INVESTING AND FINANCING ACTIVITIES:
Purchase of property and equipment recorded in accounts payable	800	745	1,631
Issuance of 109,517 shares of common stock in connection with the acquisition of LookIO on June 13, 2012	0	1,984	0
Contingent earn-out in connection with the acquisition of Engage paid in common stock recorded in accrued expenses	$ 0	$ 1,660	$ 0