Consolidated Statements Of Stockholders' Equity (USD $)	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]	Total
Balance at Dec. 31, 2009	$ 49,000	$ 190,692,000	$ (109,432,000)	$ (172,000)	$ 81,137,000
Balance (in shares) at Dec. 31, 2009	49,435,682
Repurchase of common stock	(534,496)	(3,649,000)			(3,649,000)
Common stock issued upon exercise of stock options (in shares)	2,843,547				2,843,547
Common stock issued upon exercise of stock options	3,000	11,407,000			11,410,000
Stock-based compensation		5,142,000			5,142,000
Common stock issued under Employee Stock Purchase Plan (in shares)	9,109
Common stock issued under Employee Stock Purchase Plan		74,000			74,000
Tax benefit from exercise of employee stock options		1,397,000			1,397,000
Net income			9,259,000		9,259,000
Other comprehensive loss				(127,000)	(127,000)
Balance at Dec. 31, 2010	52,000	205,063,000	(100,173,000)	(299,000)	104,643,000
Balance (in shares) at Dec. 31, 2010	51,753,842
Common stock issued upon exercise of stock options (in shares)	2,278,451				2,278,451
Common stock issued upon exercise of stock options	2,000	9,706,000			9,708,000
Stock-based compensation		6,771,000			6,771,000
Common stock issued under Employee Stock Purchase Plan (in shares)	58,051
Common stock issued under Employee Stock Purchase Plan		572,000			572,000
Tax benefit from exercise of employee stock options		4,001,000			4,001,000
Net income			12,038,000		12,038,000
Other comprehensive loss				(35,000)	(35,000)
Balance at Dec. 31, 2011	54,000	226,113,000	(88,135,000)	(334,000)	137,698,000
Balance (in shares) at Dec. 31, 2011	54,090,344
Common stock issued upon exercise of stock options (in shares)	1,634,658				1,634,658
Issuance of common stock in connection with LookIO acquisition, (in shares)	139,939				1,127,985
Issuance of common stock in connection with LookIO acquisition		1,984,000			1,984,000
Common stock issued upon exercise of stock options	2,000	8,316,000			8,318,000
Stock-based compensation		10,715,000			10,715,000
Common stock issued under Employee Stock Purchase Plan (in shares)	83,983
Common stock issued under Employee Stock Purchase Plan		1,088,000			1,088,000
Tax benefit from exercise of employee stock options		4,104,000			4,104,000
Net income			6,355,000		6,355,000
Other comprehensive loss				(19,000)	(19,000)
Balance at Dec. 31, 2012	$ 56,000	$ 252,320,000	$ (81,780,000)	$ (353,000)	$ 170,243,000
Balance (in shares) at Dec. 31, 2012	55,948,924