Stock-Based Compensation (Details) - Status Of Unvested Share-based Payment Awards (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Status Of Unvested Share-based Payment Awards [Abstract]
Shares underlying awards unvested at December 31, 2013	4,711,899
Shares underlying awards unvested at December 31, 2013	$ 1.03
Shares underlying options granted	45,958	410,000
Shares underlying options granted	$ 0.41	$ 0.58
Shares underlying restricted stock units granted	470,853	338,000
Shares underlying restricted stock units granted	$ 2.23
Shares underlying options vested	(332,057)
Shares underlying options vested	$ 0.55
Shares underlying restricted stock units vested	(262,091)	(514,000)
Shares underlying restricted stock units vested	$ 1.78
Shares underlying options cancelled	(1,722)
Shares underlying options cancelled	$ 0.54
Shares underlying restricted stock units cancelled	0
Shares underlying restricted stock units cancelled
Shares underlying awards unvested at March 31, 2014	4,632,840
Shares underlying awards unvested at March 31, 2014	$ 1.14