Shareholders' Equity Stock options and warrants (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Stock Options and Warrants [Line Items]
Stock Option Exercise	12,800
Stock Issued During Period, Shares, Other	0	3,913
Warrants Issued During Period, Value	$ 0	$ 14,900
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	1,896,700
Common Stock Warrants, Shares	4,491,028		4,898,266
Weighted Average Exercise Price, Warrants Outstanding	15.39		16.50
Weighted Average Remaining Contractual Term warrant outstanding	2 years 4 months 24 days
Aggregate Intrinsic Value, Warrants Outstanding	1,661,500
Warrants Granted	2,722
Weighted Average Exercise Price, Warrants Granted	$ 12.26
Warrants Exercised	(250,000)
Weighted Average Exercise Price, Warrants Exercised	$ 5.10
Warrants Expired	(100,108)
Weighted Average Exercise Price, Warrants Expired	$ 70.00
Warrants Canceled	(59,852)
Weighted Average Exercise Price, Warrants Canceled	$ 57.76
Proceeds from Stock Options Exercised	100,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value	1,848,900
shares, vested and expected to vest	4,491,028
Weighted Average Exercise Price, Warrants vested & expected to vest	15.39
Aggregate Intrinsic Value, Warrants vested and expected to vest	1,661,500
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value	1,600,900
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	4,473,306
Weighted Average Exercise Price, Warrants Exercisable	15.42
weighted Average Remaining Contractual Term, warrants vested	2 years 3 months 18 days
Aggregate Intrinsic Value, Warrants vested	$ 1,661,500
Warrants
Stock Options and Warrants [Line Items]
Weighted average estimated fair value of shares granted	$ 0.00		$ 3.82
US Equity Plan [Member]
Stock Options and Warrants [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	3,912,697		2,932,191
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 10.22		$ 11.19
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	7 years 4 months 21 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures	1,169,200
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price	$ 7.70
Stock Options Exercised	(12,800)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price	$ 5.58
Stock Options Expired	(109,329)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period, Weighted Average Exercise Price	$ 6.97
Stock Options Forfeited	(66,565)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price	$ 14.77
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number	3,596,457
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price	$ 10.46
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term	7 years 2 months 9 days
Weighted Average Remaining Contractual Term, Warrants Vested and Expect to Vest	2 years 4 months 24 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Number	2,520,755
Weighted average estimated fair value of shares granted	$ 11.50
Options, Vested, weighted Average Remaining Contractual Term	6 years 5 months 27 days
Minimum [Member]
Stock Options and Warrants [Line Items]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit	$ 5.20
Maximum [Member]
Stock Options and Warrants [Line Items]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit	$ 6.20