Stock-Based Compensation (Details 2) (USD $) In Thousands, except Share data, unless otherwise specified		1 Months Ended	12 Months Ended			1 Months Ended	12 Months Ended		12 Months Ended	1 Months Ended	12 Months Ended
	Dec. 31, 2012	Jul. 31, 2012 Former Chief Executive officer	Dec. 31, 2012 Stock options	Dec. 31, 2011 Stock options	Dec. 31, 2010 Stock options	Jan. 31, 2013 Stock options The 2010 Plan	Dec. 31, 2012 Stock options Directors	Dec. 31, 2012 Performance-based stock options	Dec. 31, 2012 Performance-based stock options Executive officers	Jan. 31, 2013 Restricted stock and restricted stock units The 2010 Plan	Dec. 31, 2012 Restricted stock	Dec. 31, 2011 Restricted stock
Stock-based compensation
Weighted-average fair value of stock options granted (in dollars per share)			$ 2.38	$ 3.26	$ 6.36				$ 237.00
Weighted average assumptions
Expected volatility (as a percent)			84.72%	82.10%	84.10%
Risk-free interest rate (as a percent)			0.90%	1.50%	1.90%
Expected life			6 years	6 years	6 years
Number of Shares
Outstanding at the beginning of the period (in shares)			1,784,285	1,415,106	950,693			110,338
Granted (in shares)			1,531,790	432,590	483,372		122,012		110,338
Exercised (in shares)			(42,482)	(27,534)	(4,878)
Cancelled/forfeited (in shares)			(484,994)	(35,877)	(14,081)	(1,236,837)
Outstanding at the end of the period (in shares)			2,788,599	1,784,285	1,415,106			110,338
Vested and expected to vest at the end of the period (in shares)			2,678,261
Exercisable at the end of the period (in shares)			1,450,461
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)			$ 4.31	$ 4.22	$ 1.81
Granted (in dollars per share)			$ 3.45	$ 4.69	$ 8.87
Exercised (in dollars per share)			$ 1.52	$ 1.85	$ 1.55
Cancelled/forfeited (in dollars per share)			$ 6.07	$ 7.27	$ 1.76
Outstanding at the end of the period (in dollars per share)			$ 3.58	$ 4.31	$ 4.22
Vested and expected to vest at the end of the period (in dollars per share)			$ 3.60
Exercisable at the end of the period (in dollars per share)			$ 3.23
Weighted Average Remaining Contractual Term in Years
Outstanding at the end of the period			7 years 11 months 19 days
Vested and expected to vest at the end of the period			7 years 11 months 1 day
Exercisable at the end of the period			6 years 9 months 29 days
Aggregate Intrinsic Value
Exercised			$ 72
Outstanding at the end of the period (in dollars)			1,677
Vested and expected to vest at the end of the period (in dollars)			1,642
Exercisable at the end of the period (in dollars)			1,478
Stock closing price (in dollars per share)	$ 3.38
Unrecognized compensation expense related to unvested awards			2,694
Remaining vesting period of awards			3 years 1 month 6 days							2 years	3 years 7 months 6 days
Number of in-the-money options outstanding (in shares)			1,548,053
Non-Cash expense related to modification of previously awarded equity-based awards		$ 380
Issued ( in shares)										618,415	583,325	16,000