Stock-Based Compensation (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Options Outstanding, Options	4,453,746	2,979,010	2,539,091
Options Outstanding, Weighted Average Exercise Price	$ 1.78	$ 1.34	$ 1.32
Options Outstanding, Weighted Average Remaining Contractual Life	6 years 5 months 5 days	6 years 0 months 4 days	6 years 11 months 19 days
Options Exercisable, options	2,891,877
Options Exercisable, Weighted Average Exercise Price	$ 1.60
Options Exercisable, Weighted Average Remaining Contractual Life	5 years 8 months 16 days
Range Of Exercise Price 0.09-2.00 [Member]
Options Outstanding, Options	2,162,362
Options Outstanding, Weighted Average Exercise Price	$ 1.78
Options Outstanding, Weighted Average Remaining Contractual Life	5 years 9 months 4 days
Options Exercisable, options	1,801,187
Options Exercisable, Weighted Average Exercise Price	$ 1.14
Options Exercisable, Weighted Average Remaining Contractual Life	5 years 6 months 7 days
Range Of Exercise Price 0.09-2.00 [Member] | Maximum [Member]
Range of Exercise Price	$ 2.00
Range Of Exercise Price 0.09-2.00 [Member] | Minimum [Member]
Range of Exercise Price	$ 0.09
Range Of Exercise Price 2.01-3.00 [Member]
Options Outstanding, Options	2,212,227
Options Outstanding, Weighted Average Exercise Price	$ 2.26
Options Outstanding, Weighted Average Remaining Contractual Life	7 years 1 month 24 days
Options Exercisable, options	1,011,533
Options Exercisable, Weighted Average Exercise Price	$ 2.17
Options Exercisable, Weighted Average Remaining Contractual Life	6 years 1 month 20 days
Range Of Exercise Price 2.01-3.00 [Member] | Maximum [Member]
Range of Exercise Price	$ 3.00
Range Of Exercise Price 2.01-3.00 [Member] | Minimum [Member]
Range of Exercise Price	$ 2.01
Range Of Exercise Price 3.01- 6.00 [Member]
Options Outstanding, Options	79,157
Options Outstanding, Weighted Average Exercise Price	$ 4.87
Options Outstanding, Weighted Average Remaining Contractual Life	4 years 5 months 26 days
Options Exercisable, options	79,157
Options Exercisable, Weighted Average Exercise Price	$ 4.87
Options Exercisable, Weighted Average Remaining Contractual Life	4 years 5 months 26 days
Range Of Exercise Price 3.01- 6.00 [Member] | Maximum [Member]
Range of Exercise Price	$ 6.00
Range Of Exercise Price 3.01- 6.00 [Member] | Minimum [Member]
Range of Exercise Price	$ 3.01
Range Of Exercise Price 0.09-6.00 [Member]
Options Outstanding, Options	4,453,746
Options Outstanding, Weighted Average Exercise Price	$ 1.78
Options Outstanding, Weighted Average Remaining Contractual Life	6 years 5 months 5 days
Options Exercisable, options	2,891,877
Options Exercisable, Weighted Average Exercise Price	$ 1.60
Options Exercisable, Weighted Average Remaining Contractual Life	5 years 8 months 16 days
Range Of Exercise Price 0.09-6.00 [Member] | Maximum [Member]
Range of Exercise Price	$ 6.00
Range Of Exercise Price 0.09-6.00 [Member] | Minimum [Member]
Range of Exercise Price	$ 0.09
Range Of Exercise Price 0.09-4.57 [Member]
Options Outstanding, Options		2,889,011
Options Outstanding, Weighted Average Exercise Price		$ 1.20
Options Outstanding, Weighted Average Remaining Contractual Life		6 years 1 month 10 days
Options Exercisable, options		2,364,608
Options Exercisable, Weighted Average Exercise Price		$ 1.29
Options Exercisable, Weighted Average Remaining Contractual Life		5 years 8 months 19 days
Range Of Exercise Price 0.09-4.57 [Member] | Maximum [Member]
Range of Exercise Price		$ 4.57
Range Of Exercise Price 0.09-4.57 [Member] | Minimum [Member]
Range of Exercise Price		$ 0.09
Range Of Exercise Price 4.58-9.05 [Member]
Options Outstanding, Options		89,999
Options Outstanding, Weighted Average Exercise Price		$ 5.93
Options Outstanding, Weighted Average Remaining Contractual Life		2 years 9 months 4 days
Options Exercisable, options		89,999
Options Exercisable, Weighted Average Exercise Price		$ 5.93
Options Exercisable, Weighted Average Remaining Contractual Life		2 years 9 months 4 days
Range Of Exercise Price 4.58-9.05 [Member] | Maximum [Member]
Range of Exercise Price		$ 9.05
Range Of Exercise Price 4.58-9.05 [Member] | Minimum [Member]
Range of Exercise Price		$ 4.58
Range Of Exercise Price 0.09-9.05 [Member]
Options Outstanding, Options		2,979,010
Options Outstanding, Weighted Average Exercise Price		$ 1.34
Options Outstanding, Weighted Average Remaining Contractual Life		6 years 0 months 4 days
Options Exercisable, options		2,454,607
Options Exercisable, Weighted Average Exercise Price		$ 1.46
Options Exercisable, Weighted Average Remaining Contractual Life		5 years 7 months 13 days
Range Of Exercise Price 0.09-9.05 [Member] | Maximum [Member]
Range of Exercise Price		$ 9.05
Range Of Exercise Price 0.09-9.05 [Member] | Minimum [Member]
Range of Exercise Price		$ 0.09