Summary of Significant Accounting Policies (Details) (USD $) Share data in Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Summary of Significant Accounting Policies [Abstract]
Reverse stock split conversation ratio	1-for-7 reverse stock split
Sub lease revenue	$ 100,000	$ 100,000	$ 100,000
Maximum maturity of highly liquid debt instrument	90 days
Maximum maturity to be considered as available for sale	12 months
Fair value measurements by level for assets and liabilities measured at fair value on a recurring basis
Cash equivalents	13,188,000	17,073,000
Short-term investments	24,000,000	18,058,000
Warrant liabilites	3,972,000	6,739,000
Antidilutive securities excluded from computation of earning per share amount (in shares)	11.0	8.2	2.2
Shares reserved for future issuance (in shares)	2.7
Insurance coverage reverted amount per depositor	250,000
Uninsured interest bearing deposits	12,000,000
Level I [Member]
Fair value measurements by level for assets and liabilities measured at fair value on a recurring basis
Cash equivalents	13,188,000	17,073,000
Short-term investments	24,000,000	18,058,000
Warrant liabilites	0	0
Level II [Member]
Fair value measurements by level for assets and liabilities measured at fair value on a recurring basis
Cash equivalents	0	0
Short-term investments	0	0
Warrant liabilites	0	0
Level III [Member]
Fair value measurements by level for assets and liabilities measured at fair value on a recurring basis
Cash equivalents	0	0
Short-term investments	0	0
Warrant liabilites	$ 3,972,000	$ 6,739,000
Minimum [Member]
Property, Plant and Equipment [Line Items]
Useful life	3 years
Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful life	5 years