Stock-Based Compensation (Details 1) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Options, Beginning Balance	4,453,746	2,979,010
Options, Granted	117,500	2,075,000
Options, Exercised	(291,666)	(374,851)
Options, Forfeited	(58,333)	(225,413)
Options, Ending Balance	4,221,247	4,453,746	2,979,010
Options, Exercisable	2,791,024
Weighted Average Exercise Price, Beginning Balance	$ 1.78	$ 1.34
Weighted Average Exercise Price, Granted	$ 1.74	$ 2.21
Weighted Average Exercise Price, Exercised	$ 0.79	$ 0.34
Weighted Average Exercise Price, Forfeited	$ 3.48	$ 2.37
Weighted Average Exercise Price, Ending Balance	$ 1.82	$ 1.78	$ 1.34
Weighted Average Exercise Price, Exercisable	$ 1.67
Weighted Average Remaining Contractual Life, Balance outstanding	6 years 1 month 13 days	6 years 5 months 5 days	6 years 4 days
Weighted Average Remaining Contractual Life, Balance Exercisable	5 years 5 months 9 days
Aggregate Intrinsic Value, Beginning Balance	$ 1,308,000	$ 0
Aggregate Intrinsic Value, Ending Balance	953,000	1,308,000	0
Aggregate Intrinsic Value, Exercisable	856,000
Grant date fair value of options granted	$ 185,000	$ 4,468,000
Weighted average grant date fair value	$ 1.57	$ 2.15