Fair Value Measurements (Details) (USD $)											3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended
Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2012 Fair Value, Measurements, Recurring [Member]	Dec. 31, 2011 Fair Value, Measurements, Recurring [Member]	Jun. 30, 2012 Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 1 [Member]	Dec. 31, 2011 Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 1 [Member]	Jun. 30, 2012 Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 2 [Member]	Dec. 31, 2011 Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 2 [Member]	Jun. 30, 2012 Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2011 Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 3 [Member]	Jun. 30, 2012 Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 3 [Member] Put Option [Member]	Jun. 30, 2011 Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 3 [Member] Put Option [Member]	Jun. 30, 2012 Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 3 [Member] Put Option [Member]	Jun. 30, 2011 Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 3 [Member] Put Option [Member]	Jun. 30, 2012 Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 3 [Member] Warrants [Member]	Jun. 30, 2011 Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 3 [Member] Warrants [Member]	Jun. 30, 2012 Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 3 [Member] Warrants [Member]	Jun. 30, 2011 Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 3 [Member] Warrants [Member]
Assets:
Cash equivalents			$ 22,645,000	$ 30,646,000	$ 22,645,000	$ 30,646,000	$ 0	$ 0	$ 0	$ 0
Liabilities:
Put option liability	(2,100,000)	(1,910,000)	(2,100,000)	(1,910,000)	0	0	0	0	(2,100,000)	(1,910,000)	(2,100,000)	(1,280,000)	(2,100,000)	(1,280,000)
Warrant liability			(1,008,000)	(627,000)	0	0	0	0	(1,008,000)	(627,000)					(1,008,000)	(2,809,000)	(1,008,000)	(2,809,000)
Change in Level 3 put option liability [Roll Forward]
Beginning balance	(2,100,000)	(1,910,000)	(2,100,000)	(1,910,000)	0	0	0	0	(2,100,000)	(1,910,000)	(1,640,000)	(880,000)	(1,910,000)	(1,170,000)
Decrease (increase) in fair value recognized in operating expenses											(460,000)	(400,000)	(190,000)	(110,000)	(251,000)	5,649,000	(381,000)	2,178,000
Ending balance	(2,100,000)	(1,910,000)	(2,100,000)	(1,910,000)	0	0	0	0	(2,100,000)	(1,910,000)	(2,100,000)	(1,280,000)	(2,100,000)	(1,280,000)
Change in Level 3 warrant liability [Roll Forward]
Beginning balance			(1,008,000)	(627,000)	0	0	0	0	(1,008,000)	(627,000)					(757,000)	(8,458,000)	(627,000)	(4,987,000)
Decrease (increase) in fair value recognized in operating expenses											(460,000)	(400,000)	(190,000)	(110,000)	(251,000)	5,649,000	(381,000)	2,178,000
Ending balance			$ (1,008,000)	$ (627,000)	$ 0	$ 0	$ 0	$ 0	$ (1,008,000)	$ (627,000)					$ (1,008,000)	$ (2,809,000)	$ (1,008,000)	$ (2,809,000)

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Company may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months.

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Amount of increase (decrease) of liabilities measured at fair value on a recurring basis using unobservable inputs (level 3) which have taken place during the period. Such increase (decrease) may be comprised of changes in fair value (gains or losses) whether realized or unrealized that have been included in earnings, changed net asset value, or other comprehensive income (a separate component of shareholders' equity); purchases, sales, issues, or settlements of assets; and net transfers in to or out of this category within the fair value hierarchy.

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- Definition

Value of outstanding derivative securities that permit the holder the right to purchase securities (usually equity) from the issuer at a specified price.

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