Stock-Based Compensation (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Range of Exercise Price 0.09-2.00 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit	$ 0.09	$ 0.09	$ 0.09
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit	$ 2	$ 2	$ 2
Options Outstanding, Options	2,703,280	2,093,196	2,162,362
Options Outstanding, Weighted Average Exercise Price	$ 1.37	$ 1.29	$ 1.78
Options Outstanding, Weighted Average Remaining Contractual Life	4 years 3 months 29 days	4 years 8 months 23 days	5 years 9 months 4 days
Options Exercisable, Options	2,018,074	1,901,737	1,801,187
Options Exercisable, Weighted Average Exercise Price	$ 1.28	$ 1.25	$ 1.14
Options Exercisable, Weighted Average Remaining Contractual Life	3 years 8 months 23 days	4 years 7 months 20 days	5 years 6 months 7 days
Range of Exercise Price 2.01-3.00 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit	$ 2.01	$ 2.01	$ 2.01
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit	$ 3	$ 3	$ 3
Options Outstanding, Options	3,232,002	1,770,560	2,212,227
Options Outstanding, Weighted Average Exercise Price	$ 2.49	$ 2.28	$ 2.26
Options Outstanding, Weighted Average Remaining Contractual Life	7 years 29 days	6 years 7 months 24 days	7 years 1 month 24 days
Options Exercisable, Options	1,829,298	1,205,976	1,011,533
Options Exercisable, Weighted Average Exercise Price	$ 2.40	$ 2.26	$ 2.17
Options Exercisable, Weighted Average Remaining Contractual Life	6 years 8 months 23 days	6 years 3 months	6 years 1 month 20 days
Range of Exercise Price 3.01-6.00 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit	$ 3.01	$ 3.01	$ 3.01
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit	$ 6	$ 6	$ 6
Options Outstanding, Options	45,824	45,824	79,157
Options Outstanding, Weighted Average Exercise Price	$ 5.24	$ 5.24	$ 4.87
Options Outstanding, Weighted Average Remaining Contractual Life	2 years 7 months 13 days	3 years 7 months 13 days	4 years 5 months 26 days
Options Exercisable, Options	45,824	45,824	79,157
Options Exercisable, Weighted Average Exercise Price	$ 5.24	$ 5.24	$ 4.87
Options Exercisable, Weighted Average Remaining Contractual Life	2 years 7 months 13 days	3 years 7 months 13 days	4 years 5 months 26 days
Range of Exercise Price 0.09-6.00 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit	$ 0.09	$ 0.09	$ 0.09
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit	$ 9	$ 9	$ 6
Options Outstanding, Options	5,981,106	3,909,580	4,453,746
Options Outstanding, Weighted Average Exercise Price	$ 2.01	$ 1.78	$ 1.78
Options Outstanding, Weighted Average Remaining Contractual Life	5 years 9 months 18 days	5 years 7 months 2 days	6 years 5 months 5 days
Options Exercisable, Options	3,893,196	3,153,537	2,891,877
Options Exercisable, Weighted Average Exercise Price	$ 1.85	$ 1.69	$ 1.60
Options Exercisable, Weighted Average Remaining Contractual Life	5 years 1 month 13 days	5 years 2 months 26 days	5 years 8 months 16 days