Stockholders' Equity (Details) (USD $)	12 Months Ended						12 Months Ended		48 Months Ended	1 Months Ended	3 Months Ended				1 Months Ended							1 Months Ended		12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Feb. 28, 2013	May 31, 2012	Dec. 31, 2012 Issued on 2009 [Member]	Dec. 31, 2009 Issued on 2009 [Member] Kingsbridge Capital [Member]	Dec. 31, 2009 Issued on 2009 [Member] Warrants [Member]	Nov. 30, 2009 Committed Equity Financing Facility [Member]	Jun. 30, 2012 Committed Equity Financing Facility [Member]	Dec. 31, 2012 Committed Equity Financing Facility [Member]	May 25, 2012 Committed Equity Financing Facility [Member]	Nov. 07, 2009 Committed Equity Financing Facility [Member]	Feb. 28, 2013 Shelf Registration Statement [Member]	Dec. 31, 2011 Shelf Registration Statement [Member]	Feb. 15, 2013 Shelf Registration Statement [Member]	Feb. 12, 2013 Shelf Registration Statement [Member]	Dec. 15, 2011 Shelf Registration Statement [Member]	Jun. 30, 2010 Shelf Registration Statement [Member]	Jun. 01, 2010 Shelf Registration Statement [Member]	Feb. 28, 2013 ATM Program [Member]	Jun. 30, 2012 ATM Program [Member]	Dec. 31, 2012 ATM Program [Member]	Jun. 15, 2012 ATM Program [Member]
Stockholders' Equity (Textual) [Abstract]
Common stock shares, purchase by Kingsbridge													$ 45,000,000												$ 20,000,000
Common stock purchase by Kingsbridge													3,327,000
Contractual term of warrant										5 years
Common Stock shares issued for warrants exercisable					775,000									200,000
Aggregate initial offering price on self registration statement																					75,000,000
Deferred financing costs, comprised of legal, accounting, and other costs associated with CEFF agreement											62,000
Public offering of common stock shares under underwriting agreement																		6,100,000	5,000,000	2,200,000
Initial public offering price per share																		$ 1.30	$ 3.25	$ 7.50
Gross proceeds from sale of common stock															7,900,000	16,300,000							20,000,000	5,600,000
Net proceeds from sale of common stock																		7,300,000	15,000,000					5,400,000
Amount available under shelf registration statement																	19,900,000							22,200,000
Previously allocated amount under shelf registration statement	5,201,896	15,024,662	15,233,671																			5,600,000
Common stock, shares issued	32,204,720	30,307,538																						1,863,830
Remaining Available common stock under the ATM Program																								14,400,000
Company issued warrants								200,000				200,000
Warrants Issued									1,200,000
Common Stock shares issued for warrants, Exercise Price							11.35							11.35
Expiry date for warrants outstanding							May 01, 2014
Stockholders' Equity (Additional Textual) [Abstract]
Common stock shares sold under the CEFF agreement			406,744	1,824,941
Common stock shares unsold on termination of CEFF						1,095,315
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, par value	$ 0.10	$ 0.10
Preferred stock, shares issued
Preferred stock, shares outstanding
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	45,000,000	45,000,000
Common stock, shares outstanding	32,204,720	30,307,538
Warrants exercised or expired	1,000,000
Warrant outstanding	200,000
Venture capital loan					$ 10,000,000