Stockholders' Equity, Committed Equity Financing Facility (Details) (USD $)					0 Months Ended						13 Months Ended
	Dec. 31, 2012	Jun. 11, 2010 June 2010 Warrant [Member]	Dec. 31, 2008 December 2008 Warrant [Member]	Dec. 31, 2008 May 2008 Warrant [Member]	Nov. 08, 2011 June 2010 CEFF [Member]	Oct. 24, 2011 June 2010 CEFF [Member]	Oct. 10, 2011 June 2010 CEFF [Member]	Jan. 24, 2011 June 2010 CEFF [Member]	Nov. 04, 2010 June 2010 CEFF [Member]	Oct. 04, 2010 June 2010 CEFF [Member]	Nov. 08, 2011 June 2010 CEFF [Member]	Dec. 31, 2012 June 2010 CEFF [Member]	Dec. 31, 2011 June 2010 CEFF [Member]	Jun. 11, 2010 June 2010 CEFF [Member]	Jun. 11, 2010 June 2010 CEFF [Member] Range 1 [Member]	Jun. 11, 2010 June 2010 CEFF [Member] Range 2 [Member]	Jun. 11, 2010 June 2010 CEFF [Member] Range 3 [Member]	Jun. 11, 2010 June 2010 CEFF [Member] Range 4 [Member]	Jun. 11, 2010 June 2010 CEFF [Member] Range 5 [Member]	Jun. 11, 2010 June 2010 CEFF [Member] Range 6 [Member]	Jun. 11, 2010 June 2010 CEFF [Member] Range 7 [Member]	Jun. 11, 2010 June 2010 CEFF [Member] Range 8 [Member]	Jun. 11, 2010 June 2010 CEFF [Member] Range 9 [Member]	Jun. 11, 2010 June 2010 CEFF [Member] Range 10 [Member]
Stockholders' Equity [Line Items]
Common stock available for issuance (in shares)	40,300,000											1,074,114	1,074,114	2,100,000
Maximum value of potential common stock available for issue													$ 32,300,000	$ 35,000,000
Equity draw down provisions														Each draw down extends for an eight-day trading period. To initiate a draw down, the closing price of our common stock on the trading day immediately preceding the first trading day must be at least equal to $0.20 per share. If on any trading day during the trading period, if the daily volume-weighted average price of our common stock (VWAP) is less than the Threshold Price (defined below), Kingsbridge has the right to purchase shares at the Threshold Price; otherwise no shares are purchased on that trading day and the aggregate amount that we originally designated for the overall draw down is reduced for each such day by 1/8th. The Threshold Price is either (i) 90% of the closing market price of our common stock on the trading day immediately preceding the first trading day of the draw down period or (ii) a price that we specify at our sole discretion; but not less than $0.20 per share. Unless Kingsbridge and we agree otherwise, a minimum of three trading days must elapse between the expiration of any draw-down period and the beginning of the next draw-down period.With respect to each draw down, Kingsbridge is obligated to purchase ("Obligated Amount") the amount determined under one of two methodologies that we choose at our discretion, subject to a maximum of the lesser of 3.5% of the closing market value of the outstanding shares of our common stock at the time of the draw down or $15 million.
Draw down trading period														8 days
Common stock closing price, minimum (in dollars per share)														$ 0.20
Percentage closing market price of common stock (in hundredths)														90.00%
Period between expiration of old draw down period and beginning of new draw down														3 days
Percentage of closing market value of outstanding shares of common stock at draw down (in hundredths)														3.50%
Maximum obligated amount under second option														15,000,000
Period of average daily trading volume														40 days
Period of highest trading volume														5 days
Period of lowest trading volume														5 days
Threshold price under Methodology 2 (in dollars per share)														$ 0.1985
CEFF Threshold Price Range, Greater than or equal to (in dollars per share)															$ 90.00	$ 75.00	$ 60.00	$ 45.00	$ 30.00	$ 18.75	$ 11.25	$ 7.50	$ 3.75	$ 3.00
CEFF Threshold Price Range, Less than (in dollars per share)																$ 90.00	$ 75.00	$ 60.00	$ 45.00	$ 30.00	$ 18.75	$ 11.25	$ 7.50	$ 3.75
Obligated Amount Methodology 1															7,250,000	6,500,000	4,250,000	3,500,000	2,750,000	2,000,000	1,350,000	1,000,000	500,000	350,000
Obligated Amount Methodology 2														Under this method, the Obligated Amount is equal to: 8 (the trading days in the draw down period) multiplied by the adjusted average trading volume of our common stock (calculated as the average daily trading volume of the prior 40 trading days excluding the 5 trading days with the highest trading volume and the 5 trading days with the lowest trading volume) multiplied by the Threshold Price multiplied by 0.1985.
Supplemental Amount of Drawdown														In addition, the 2010 CEFF provides that in connection with any draw down notice we may, in our sole discretion, include a request that Kingsbridge purchase an additional amount over the calculated Obligated Amount (a supplemental amount). Kingsbridge may in its sole discretion choose to purchase all or a portion of any supplemental amount that we designate. If we designate a supplemental amount, we may also designate a separate threshold price for that supplemental amount, provided that the supplemental amount, when aggregated with all other amounts drawn under the 2010 CEFF, may not exceed the total commitment amount available under the 2010 CEFF. If Kingsbridge elects to purchase any of the supplemental amount, we will sell to Kingsbridge the corresponding number of shares at a price equal to the greater of (i) the daily VWAP of our common stock on the applicable trading day, or (ii) the supplemental amount threshold price designated by us, in either case less the applicable discount determined in the same manner as for the Obligated Amount.
VWAP Range, Greater than or equal to (in dollars per share)															$ 6.00	$ 5.00	$ 4.00	$ 3.00	$ 2.00	$ 1.25	$ 0.75	$ 0.50	$ 0.25	$ 0.20
VWAP Range, Less than (in dollars per share)																$ 6.00	$ 5.00	$ 4.00	$ 3.00	$ 2.00	$ 1.25	$ 0.75	$ 0.50	$ 0.25
Purchase Price Percent of VWAP (in hundredths)															95.62%	95.25%	94.75%	94.25%	94.00%	92.50%	91.50%	90.50%	85.00%	82.50%
Applicable Discount Percent of VWAP (in hundredths)															4.38%	4.75%	5.25%	5.75%	6.00%	7.50%	8.50%	9.50%	15.00%	17.50%
Period of adverse event affecting business continuity														10 days
Number of shares callable by warrants (in shares)		83,333	45,000	55,000
Exercise price of warrants (in dollars per share)		$ 6.69	$ 22.70	$ 37.59
Shares Issued (in shares)					129,000	37,000	35,000	314,000	166,000	351,000	1,032,000
Gross proceeds					$ 218,000	$ 63,000	$ 69,000	$ 991,000	$ 432,000	$ 973,000	$ 2,746,000
Discounted Average Price Per Share (in dollars per share)					$ 1.69	$ 1.71	$ 1.97	$ 3.16	$ 2.60	$ 2.77