CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (loss)	Accumulated Deficit
Beginning balances at Dec. 31, 2009	$ 11,693	$ 3	$ 188,078	$ 931	$ (177,319)
Beginning balances (in shares) at Dec. 31, 2009		30,360
Net loss	(13,423)				(13,423)
Stock-based compensation expense	1,568		1,568
Vesting of early exercised options	2		2
Issuance of common stock upon exercise of stock options (in shares)		330
Issuance of common stock upon exercise of stock options	287		287
Issuance of common stock upon Private Placement, net of issuance costs (shares)		13,495
Issuance of common stock upon exercise of warrants, shares		0
Issuance of common stock upon Private Placement, net of issuance costs	13,219	1	13,218
Issuance of common stock pursuant to Employee Stock Purchase Plan (in shares)		400
Issuance of common stock pursuant to Employee Stock Purchase Plan	311		311
Foreign currency translation adjustment	228			228
Ending balances at Dec. 31, 2010	13,885	4	203,464	1,159	(190,742)
Ending balances (in shares) at Dec. 31, 2010		44,585
Net loss	(21,101)				(21,101)
Stock-based compensation expense	2,559		2,559
Issuance of other common stock (in shares)		51
Issuance of other common stock	200		200
Issuance of common stock upon exercise of stock options (in shares)		859
Issuance of common stock upon exercise of stock options	1,633		1,633
Issuance of common stock upon exercise of warrants, shares		2,475
Issuance of common stock upon exercise of warrants	3,711		3,711
Issuance of common stock as consideration for acquisition (in shares)		7,106
Issuance of common stock as consideration for acquisition	33,158	1	33,157
Issuance of common stock upon Secondary Offering, net of issuance costs (in shares)		8,415
Issuance of common stock upon Secondary Offering, net of issuance costs	15,661	1	15,660
Issuance of common stock pursuant to Employee Stock Purchase Plan (in shares)		258
Issuance of common stock pursuant to Employee Stock Purchase Plan	360		360
Foreign currency translation adjustment	(893)			(893)
Ending balances at Dec. 31, 2011	49,173	6	260,744	266	(211,843)
Ending balances (in shares) at Dec. 31, 2011		63,749
Net loss	(20,459)				(20,459)
Stock-based compensation expense	4,271		4,271
Issuance of common stock upon exercise of stock options (in shares)		806
Issuance of common stock upon exercise of stock options	1,357		1,357
Issuance of common stock upon exercise of warrants, shares		413
Issuance of common stock upon exercise of warrants	619		619
Issuance of common stock as consideration for acquisition (in shares)		600
Issuance of common stock as consideration for acquisition	2,796		2,796
Issuance of common stock pursuant to Employee Stock Purchase Plan (in shares)		454
Issuance of common stock pursuant to Employee Stock Purchase Plan	1,229		1,229
Foreign currency translation adjustment	(99)			(99)
Ending balances at Dec. 31, 2012	$ 38,887	$ 6	$ 271,016	$ 167	$ (232,302)
Ending balances (in shares) at Dec. 31, 2012		66,022