Liquidity Risks and Management's Plans (Details) (USD $)						0 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2014 Deerfield Management Company [Member]	Feb. 22, 2011 Issued February 22, 2011 [Member]	Jun. 30, 2014 Issued February 22, 2011 [Member]	Jun. 30, 2014 ATM Program [Member]
Liquidity Risks and Management's Plans [Abstract]
Cash and cash equivalents	$ 65,557,000	$ 86,283,000	$ 31,253,000	$ 26,892,000
Long-Term Debt	30,000,000
Long-term debt, carrying amount	19,264,000	18,354,000
Stockholders' Equity [Line Items]
Maximum value of potential common stock available for issue								$ 23,000,000
Class of Warrant or Right [Line Items]
Number of warrant shares outstanding (in shares)	14,000,000				7,000,000
Exercise price of warrants (in dollars per share)					$ 2.81	$ 1.50	$ 1.50
Exercisable period of warrants						5 years
Number of warrant shares issuable (in shares)						4,552,600	4,600,000
Common stock, shares authorized (in shares)	250,000,000	150,000,000
Common stock available for future issuance (in shares)	137,200,000