Share-based Compensation (Details 4) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Number of Shares
Balance at beginning of year (in shares)	3,383,554	3,341,575	2,936,392
Granted (in shares)	1,488,300	950,222	732,081
Forfeited (in shares)	(593,476)	(495,396)	(123,875)
Expired (in shares)	(933,496)	(399,864)	(180,223)
Exercised (in shares)	0	(12,983)	(22,800)
Balance at end of year (in shares)	3,344,882	3,383,554	3,341,575
Exercisable at end of year (in shares)	1,833,719	2,304,154	2,129,510
Additional shares available for grant at end of year	2,190,092	2,371,405	1,146,683
Weighted Average Exercise Price
Balance at beginning of year (in dollars per share)	$ 7.78	$ 9.51	$ 10.20
Granted (in dollars per share)	$ 1.19	$ 2.69	$ 8.20
Forfeited (in dollars per share)	$ 1.73	$ 7.63	$ 10.88
Expired (in dollars per share)	$ 10.04	$ 10.55	$ 15.20
Exercised (in dollars per share)	$ 0.00	$ 3.24	$ 3.48
Balance at end of year (in dollars per share)	$ 5.20	$ 7.78	$ 9.51
Exercisable at end of year (in dollars per share)	$ 8.04	$ 8.94	$ 8.68
Additional disclosures
Weighted average grant date fair value (in dollars per share)	$ 0.61	$ 1.89	$ 5.72
Weighted average remaining contractual term for options outstanding (in years)	6 years 9 months 18 days
Weighted average remaining contractual term for options exercisable (in years)	4 years 10 months 24 days
Unrecognized stock-based compensation cost	$ 945,000
Weighted average period over which unrecognized stock-based compensation cost is expected to be expensed	1 year 4 months 24 days
Total fair value of shares vested	2,402,000	4,405,000	3,996,000
Intrinsic value of outstanding, vested and currently exercisable share options	$ 0