Stockholders' Equity (Schedule of Warrants) (Details)				9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Sep. 30, 2013 Warrant Tranche One [Member]		Sep. 30, 2013 Warrant Tranche Two [Member]		Sep. 30, 2013 Warrant Tranche Three [Member]		Sep. 30, 2013 Warrant Tranche Four [Member]		Sep. 30, 2013 Warrant Tranche Five [Member]		Sep. 30, 2013 Warrant Tranche Six [Member]		Sep. 30, 2013 Warrant Tranche Seven [Member]
Class of Warrant or Right [Line Items]
Number of Common Shares Underlying Warrants	5,620,128	5,620,128	5,620,128	100,778	[1]	705,354	[2]	2,572,775	[1]	500,000	[2]	1,323,214	[2]	371,423	[2]	46,584	[1]
Issue Date				Mar. 01, 2007		Mar. 01, 2009		Jul. 01, 2009		Apr. 01, 2010		Jul. 01, 2010		Jun. 01, 2011		Mar. 01, 2012
Exercisable Date				Mar. 01, 2007		Sep. 01, 2009		Jan. 01, 2010		Oct. 01, 2010		Jan. 01, 2011		Jun. 01, 2011		Mar. 01, 2012
Exercise Price				3.97		3.00		2.50		1.89		1.63		3.50		1.61
Expiration Date				Mar. 31, 2017		Sep. 30, 2014		Jan. 31, 2015		Oct. 31, 2015		Jan. 31, 2017		Jun. 30, 2016		Mar. 31, 2022

[1] These warrants to purchase common stock are classified as equity.

[2] Because of the presence of net settlement provisions, these warrants to purchase common stock are classified as derivative liabilities. The fair value of these liabilities (see Note 4) is remeasured at the end of every reporting period and the change in fair value is reported in the unaudited condensed consolidated statements of operations as other income (expense).