Consolidated Statements Stockholders' Equity (USD $) In Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]
Beginning balance at Dec. 31, 2010	$ 107,361	$ 4	$ 275,540	$ (34)	$ (168,149)
Beginning balance (shares) at Dec. 31, 2010		34,829
Exercise of stock options	2,579		2,579
Exercise of stock options (shares)		1,167
Employee stock-based compensation	9,286		9,286
Non-employee stock-based compensation	387		387
Total comprehensive loss	(16,923)			(373)	(16,550)
Ending balance at Dec. 31, 2011	102,690	4	287,792	(407)	(184,699)
Ending balance (shares) at Dec. 31, 2011		35,996
Exercise of common warrants (shares)	0	3
Exercise of stock options	1,257		1,257
Exercise of stock options (shares)		708
Cancellation of shares	(65)		(65)
Cancellation of shares (shares)		(17)
Release of stock awards (shares)		982
Employee stock-based compensation	5,040		5,040
Non-employee stock-based compensation	104		104
Non-employee stock-based compensation (shares)		20
Total comprehensive loss	(30,586)			271	(30,857)
Ending balance at Dec. 31, 2012	78,440	4	294,128	(136)	(215,556)
Ending balance (shares) at Dec. 31, 2012		37,692
Exercise of stock options	318		318
Exercise of stock options (shares)		326
Cancellation of shares	(465)		(465)
Cancellation of shares (shares)		(75)
Release of stock awards (shares)		408
Employee stock-based compensation	4,366		4,366
Non-employee stock-based compensation	23		23
Total comprehensive loss	(41,199)			104	(41,303)
Ending balance at Dec. 31, 2013	$ 41,483	$ 4	$ 298,370	$ (32)	$ (256,859)
Ending balance (shares) at Dec. 31, 2013		38,351