CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
OPERATING ACTIVITIES:
Net (loss) income	$ (2,791)	$ 4,863
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Stock-based compensation expense	9,749	7,646
Depreciation	6,050	5,170
Amortization of purchased intangibles	1,575	294
Deferred income taxes	(1,700)	(1,325)
Provision for doubtful accounts, net	0	20
Changes in operating assets and liabilities:
Accounts receivable	(7,395)	(1,846)
Prepaid expenses and other current assets	(1,523)	(1,617)
Other assets	79	(81)
Accounts payable	(3,523)	1,129
Accrued expenses	2,978	2,121
Deferred revenue	261	1,373
Other liabilities	(112)	(81)
Net cash provided by operating activities	3,648	17,666
INVESTING ACTIVITIES:
Purchases of property and equipment, including capitalized software	(6,638)	(6,919)
Acquisition of LookIO, net of cash acquired	0	(900)
Acquisition of Amadesa technology assets	0	(10,798)
Acquisition of Proficient	0	(77)
Acquisition of domains	(50)	0
Acquisition costs - Engage, net of cash	(79)	0
Net cash used in investing activities	(6,767)	(18,694)
FINANCING ACTIVITIES:
Excess tax benefit from the exercise of employee stock options	135	2,607
Proceeds from issuance of common stock in connection with the exercise of options	3,737	8,557
Repurchase of common stock	(26,716)	0
Net cash (used in) provided by financing activities	(22,844)	11,164
EFFECT OF FOREIGN EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS	3	(130)
CHANGE IN CASH AND CASH EQUIVALENTS	(25,960)	10,006
CASH AND CASH EQUIVALENTS - Beginning of the period	103,339	93,278
CASH AND CASH EQUIVALENTS - End of the period	77,379	103,284
SUPPLEMENTAL DISCLOSURE OF OTHER CASH FLOW INFORMATION:
Cash paid for income taxes	151	1,556
SUPPLEMENTAL DISCLOSURE OF NON-CASH INVESTING AND FINANCING ACTIVITIES:
Purchase of property and equipment recorded in accounts payable	720	1,952
Issuance of 109,517 shares of common stock in connection with the acquisition of LookIO on June 13, 2012	$ 0	$ 1,984