Fair Value Measurements (Details) (USD $)	Dec. 31, 2012	Dec. 31, 2011
Assets
Cash	$ 18,653,000	$ 25,128,000
Liabilities
Warrant liability	830,000	450,000
Level 3
Liabilities
Warrant liability	800,000
Other liability	24,400,000
Stock liability	200,000
Recurring basis | Level 1
Assets
Cash	1,134,000	5,003,000
Money Market Funds	16,020,000	20,125,000
Assets fair value	17,154,000	25,128,000
Recurring basis | Level 2
Assets
Assets fair value	5,499,000	31,580,000
Recurring basis | Level 2 | Domestic corporate debt securities
Assets
Marketable securities		10,254,000
Recurring basis | Level 2 | Domestic corporate commercial paper
Assets
Money Market Funds	1,499,000
Marketable securities	4,000,000	18,998,000
Recurring basis | Level 2 | U.S Government Securities
Assets
Marketable securities		2,328,000
Recurring basis | Level 3
Assets
Stock asset	407,000	3,379,000
Assets fair value	407,000	3,379,000
Liabilities
Warrant liability	830,000	450,000
Other liability	24,387,000	10,470,000
Stock liability	245,000
Total liabilities carried at fair value	25,462,000	10,920,000
Recurring basis | Estimated Fair Value
Assets
Cash	1,134,000	5,003,000
Money Market Funds	16,020,000	20,125,000
Stock asset	407,000	3,379,000
Assets fair value	23,060,000	60,087,000
Liabilities
Warrant liability	830,000	450,000
Other liability	24,387,000	10,470,000
Stock liability	245,000
Total liabilities carried at fair value	25,462,000	10,920,000
Recurring basis | Estimated Fair Value | Domestic corporate debt securities
Assets
Marketable securities		10,254,000
Recurring basis | Estimated Fair Value | Domestic corporate commercial paper
Assets
Money Market Funds	1,499,000
Marketable securities	4,000,000	18,998,000
Recurring basis | Estimated Fair Value | U.S Government Securities
Assets
Marketable securities		$ 2,328,000