Shareholders' Equity Stock options and warrants (Details) (USD $)	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Stock Options and Warrants [Line Items]
Stock Issued During Period, Shares, Other	0	20,407
Warrants Issued During Period, Value	$ 0	$ 71,600
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	1,657,400	1,658,100
Common Stock Warrants, Shares	3,623,956		4,898,266
Weighted Average Exercise Price, Warrants Outstanding	13.96		16.50
Weighted Average Remaining Contractual Term warrant outstanding	2 years 7 months 17 days	2 years 7 months 17 days
Aggregate Intrinsic Value, Warrants Outstanding	1,080,200	1,811,000
Warrants Granted	2,722
Weighted Average Exercise Price, Warrants Granted	$ 12.26
Warrants Exercised	(265,250)
Weighted Average Exercise Price, Warrants Exercised	$ 5.18
Warrants Expired	(100,108)
Weighted Average Exercise Price, Warrants Expired	$ 70.00
Warrants Canceled	(911,674)
Weighted Average Exercise Price, Warrants Canceled	$ 23.97
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value	1,592,800
shares, vested and expected to vest	3,623,956
Weighted Average Exercise Price, Warrants vested & expected to vest	13.96
Aggregate Intrinsic Value, Warrants vested and expected to vest	1,080,200
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value	1,123,200
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	3,611,456
Weighted Average Exercise Price, Warrants Exercisable	13.98
weighted Average Remaining Contractual Term, warrants vested	2 years 7 months 13 days
Aggregate Intrinsic Value, Warrants vested	$ 1,080,200
Warrants
Stock Options and Warrants [Line Items]
Weighted average estimated fair value of shares granted	$ 0.00		$ 3.51
US Equity Plan [Member]
Stock Options and Warrants [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	4,204,270		2,932,191
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 9.67		$ 11.19
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	7 years 6 months 26 days	6 years 9 months 22 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures	1,653,325
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price	$ 7.05
Stock Options Exercised	(41,136)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price	$ 5.60
Stock Options Expired	(189,454)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period, Weighted Average Exercise Price	$ 6.34
Stock Options Forfeited	(150,656)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price	$ 15.78
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number	3,891,887
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price	$ 9.86
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term	7 years 4 months 28 days
Weighted Average Remaining Contractual Term, Warrants Vested and Expect to Vest	2 years 7 months 17 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Number	2,533,802
Weighted average estimated fair value of shares granted	$ 11.16
Options, Vested, weighted Average Remaining Contractual Term	6 years 6 months 18 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