Earnings Per Share (Details) (USD $)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Outstanding equity awards not included in the calculation of diluted net loss per share:
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period			(31,000)		(27,000)
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount				0
Shares Paid for Tax Withholding for Share Based Compensation			(147,000)		(485,000)
Stock options
Outstanding equity awards not included in the calculation of diluted net loss per share:
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	7,299,887	9,298,263	8,725,951	9,298,263
Range of exercise prices, lower limit	$ 1.26	$ 0.47	$ 1.06	$ 0.47
Range of exercise prices, upper limit	$ 16.36	$ 16.36	$ 16.36	$ 16.36
Unvested restricted stock awards
Outstanding equity awards not included in the calculation of diluted net loss per share:
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	5,550	1,132,568	11,753	1,132,568
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period			(23,000)		(495,000)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross			30,000		844,000
Warrant [Member]
Outstanding equity awards not included in the calculation of diluted net loss per share:
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1,602,489	1,602,489	1,602,489	1,602,489
Warrants, exercise price	2.40	2.40	2.40	2.40
2000ESPP [Member]
Outstanding equity awards not included in the calculation of diluted net loss per share:
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period			458,000		675,000