Condensed Consolidated Statements Of Redeemable Convertible Preferred Stock And Stockholders' Equity (Deficit) (USD $) In Thousands, except Share data	Redeemable Convertible Preferred Stock [Member]	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Notes Receivable From Stockholders [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Deficit [Member]	Total
Balance at Dec. 31, 2010	$ 128,313		$ 12	$ 4,393	$ (1,597)	$ (40)	$ (52,835)	$ (50,067)
Balance, Shares at Dec. 31, 2010	34,534,125		12,067,090
Issuance of common stock to consultant for services rendered				16				16
Issuance of common stock to consultant for services rendered, shares			2,000
Issuance of common stock upon exercise of stock options			1	408				409
Issuance of common stock upon exercise of stock options, shares			567,763
Restricted stock issued to nonemployees related to services performed				423				423
Restricted stock issued to nonemployees related to services performed, shares			32,708
Stock-based compensation related to employees				3,976				3,976
Stock-based compensation related to nonemployees				3,176				3,176
Interest earned on stockholder promissory notes					(4)			(4)
Accretion of redeemable convertible preferred stock	60						(60)	(60)
Payments received on notes receivable from stockholders					1,601			1,601
Shares issued for initial public offering, net of offering costs			12	197,016				197,028
Shares issued for initial public offering, net of offering costs, shares			12,021,250
Conversion of redeemable convertible preferred stock at initial public offering	(128,373)		35	128,339				128,374
Conversion of redeemable convertible preferred stock at initial public offering, shares	(34,534,125)		34,534,125
Conversion of preferred stock warrant to redeemable convertible preferred stock at initial public offering, shares	303,855
Conversion of redeemable convertible preferred stock to common stock at initial public offering, shares	(303,855)		303,855
Exercise of preferred stock warrant				25				25
Exercise of preferred stock warrant, shares			64,103
Conversion of convertible preferred stock warrants to common stock and common stock warrants				6,598				6,598
Exercise of common stock warrants				12				12
Exercise of common stock warrants, shares			5,000
Components of comprehensive loss
Change in unrealized loss on available-for-sale securities						(343)		(343)
Foreign currency translation adjustment						(383)		(383)
Net loss							(38,320)	(38,320)
Comprehensive loss								(39,046)
Balance at Sep. 30, 2011			$ 60	$ 344,382		$ (766)	$ (91,215)	$ 252,461
Balance, shares at Sep. 30, 2011			59,597,894