Share-based compensation (Schedule Of Stock Option Activity) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Share-Based Compensation Schedule Of Stock Option Activity Details
Options, Outstanding as of beginning of period	964,000	1,092,000
Options, Granted	671,000	121,000
Options, Exercised	(16,000)	(5,000)
Options, Forfeited, cancelled or expired	(301,000)	(244,000)
Options, Outstanding as of end of period	1,318,000	964,000
Weighted-Average Exercise Prices, Outstanding as of beginnig of period	$ 24.00	$ 27.20
Weighted-Average Exercise Prices, Granted	$ 1.97	$ 10.00
Weighted-Average Exercise Prices, Exercised	$ 1.80	$ 15.12
Weighted-Average Exercise Prices, Forfeited, cancelled or expired	$ 21.20	$ 31.60
Weighted-Average Exercise Prices, Outstanding as of end of period	$ 13.71	$ 24.00
Options Outstanding, Weighted-Average Remaining Contractual Term (in years)	6.8	5.8	5.9
Options, Outstanding, Aggregate Intrinsic Value	$ 61,871	$ 0	$ 96,309
Options, Vested and expected to vest at end of period	1,285,000
Weighted-Average Exercise Price, Vested and expected to vest	$ 13.97
Weighted-Average Remaining Contractual Term (in years), Vested and expected to vest	6.7
Options, Vested and expected to vest, Aggregate Intrinsic Value	59,481
Options, Exercisable at end of period	777,000
Weighted-Average Exercise Price, Exercisable	$ 20.34
Weighted-Average Remaining Contractual Term (in years), Exercisable	5.4
Options, Exercisable, Aggregate Intrinsic Value	20,444
Options, Exercises in Period, Intrinsic Value	13,000	12,000
Options, Vested, Aggregate Intrinsic Value	$ 2,500,000	$ 4,100,000