Share-Based Payment Arrangements (Details) (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013 Plan	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock incentive plans	2
Number of employee stock purchase plans	2
Options, Outstanding [Roll Forward]
Outstanding, Beginning balance (in shares)	5,366
Granted (in shares)	1,018
Exercised (in shares)	(14)
Forfeited	(608)
Expired	(463)
Outstanding, Ending balance (in shares)	5,299	5,366
Exercisable (in shares)	3,875
Weighted Average Exercise Price [Roll Forward]
Outstanding, Beginning balance (in dollars per share)	$ 12.27
Granted (in dollars per share)	$ 5.13
Exercised (in dollars per share)	$ 5.08
Forfeited (in dollars per share)	$ 10.63
Expired (in dollars per share)	$ 14.70
Outstanding, Ending balance (in dollars per share)	$ 10.89	$ 12.27
Exercisable (in dollars per share)	$ 12.45
Weighted Average Remaining Contractual Term [Abstract]
Options Outstanding	5 years 9 months 25 days
Options Exercisable	4 years 10 months 10 days
Aggregate Intrinsic Value [Abstract]
Options Outstanding	$ 304,000
Options Exercisable	118,000
Total compensation expense recognized	3,546,000	6,536,000	6,362,000
Employee stock purchase plan [Abstract]
Cash received from exercises under all share-based payment arrangements	100,000
Employees [Member]
Assumptions used in computing the fair value [Abstract]
Expected term	5 years 4 months 24 days	5 years 3 months 18 days	5 years 3 months 18 days
Former CEO [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	9 years 11 months
Assumptions used in computing the fair value [Abstract]
Expected term			8 years
Aggregate Intrinsic Value [Abstract]
Estimated requisite service periods	9 years 11 months
Non Employees [Member]
Assumptions used in computing the fair value [Abstract]
Expected term	10 years
Directors and Officers [Member]
Assumptions used in computing the fair value [Abstract]
Expected term	7 years 4 months 24 days	7 years 4 months 24 days	7 years 3 months 18 days
Options [Member]
Assumptions used in computing the fair value [Abstract]
Expected volatility, minimum (in hundredths)	73.00%	70.00%	68.00%
Expected volatility, maximum (in hundredths	90.00%	85.00%	78.00%
Expected dividends (in hundredths)	0.00%	0.00%	0.00%
Weighted average expected term (years)	5 years 11 months 16 days	6 years 1 month 10 days	6 years 2 months 1 day
Risk-free rate, minimum (in hundredths)	0.76%	0.57%	0.77%
Risk-free rate, maximum (in hundredths)	2.83%	1.71%	2.97%
Employee stock purchase plan [Abstract]
Total unrecognized compensation	4,400,000
Weighted average periods	2 years 1 month 6 days
Options [Member] | Minimum [Member]
Assumptions used in computing the fair value [Abstract]
Expected term	5 years 3 months 18 days	5 years 3 months 18 days	5 years 3 months 18 days
Options [Member] | Maximum [Member]
Assumptions used in computing the fair value [Abstract]
Expected term	10 years	10 years	10 years
Restricted stock [Member]
Restricted Stock [Roll Forward]
Nonvested, Beginning balance (in shares)	28
Granted (in shares)	0
Vested (in shares)	(27)
Forfeited (in shares)	(1)
Nonvested, Ending balance (in shares)	0		98
Restricted Stock, Weighted Average Grant-Date Fair Value [Roll Forward]
Nonvested, Beginning balance (in dollars per share)	$ 5.35
Granted (in dollars per share)	$ 0
Vested (in dollars per share)	$ 5.35
Forfeited (in dollars per share)	$ 5.35
Nonvested, Ending balance (in dollars per share)	$ 0
Performance-based options [Member]
Aggregate Intrinsic Value [Abstract]
Total compensation expense recognized	100,000	2,000,000	400,000
2006 Award [Member] | Options [Member]
Aggregate Intrinsic Value [Abstract]
Estimated requisite service periods	2 years 6 months
2011 Award [Member] | Options [Member]
Aggregate Intrinsic Value [Abstract]
Estimated requisite service periods	1 year
2012 Award [Member] | Options [Member]
Aggregate Intrinsic Value [Abstract]
Estimated requisite service periods	1 year
1996 Plan and 2005 Plan [Member] | Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration term	10 years
Aggregate Intrinsic Value [Abstract]
Weighted average grant-date fair value of options granted (in dollars per share)	$ 3.74	$ 6.38	$ 5.51
Total Intrinsic Value of options exercised	$ 11,000	$ 174,000	$ 345,000
1996 Plan and 2005 Plan [Member] | Options [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
1996 Plan and 2005 Plan [Member] | Options [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	5 years
1996 Plan and 2005 Plan [Member] | Restricted stock [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
1996 Plan and 2005 Plan [Member] | Restricted stock [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	5 years
1996 Amended Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance of awards (in shares)	5,000
2005 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance of awards (in shares)	8,450
Employee Stock Purchase Plan [Member]
Assumptions used in computing the fair value [Abstract]
Expected volatility, minimum (in hundredths)			43.00%
Expected volatility, maximum (in hundredths			51.00%
Expected dividends (in hundredths)			0.00%
Expected term			6 months
Risk-free rate, minimum (in hundredths)			0.06%
Risk-free rate, maximum (in hundredths)			0.22%
Employee Stock Purchase Plan [Member] | Options [Member]
Assumptions used in computing the fair value [Abstract]
Expected term			6 months
Restricted Stock, Weighted Average Grant-Date Fair Value [Roll Forward]
Percentage of quarterly compensation, grant to all employees (in hundredths)			25.00%
Discounted price as percentage of the fair market value (in hundredths)			85.00%
Qualified Employee Stock Purchase Plan 1998 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance of awards (in shares)	4,400
Employee stock purchase plan [Abstract]
Shares Purchased (in shares)			428
Weighted Average Grant-date Fair value (in dollars per share)			$ 0.88
Qualified Employee Stock Purchase Plan 1998 [Member] | Minimum [Member]
Employee stock purchase plan [Abstract]
Price Range (in dollars per share)			$ 4.62
Qualified Employee Stock Purchase Plan 1998 [Member] | Maximum [Member]
Employee stock purchase plan [Abstract]
Price Range (in dollars per share)			$ 5.65
Qualified Employee Stock Purchase Plan 1998 [Member] | Options [Member]
Restricted Stock, Weighted Average Grant-Date Fair Value [Roll Forward]
Maximum percentage of common stock ownership to be eligible for employee stock purchase plans (in hundredths)			5.00%
Non-Qualified Employee Purchase Plan 1998 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance of awards (in shares)	1,100
Employee stock purchase plan [Abstract]
Shares Purchased (in shares)			162
Weighted Average Grant-date Fair value (in dollars per share)			$ 0.84
Non-Qualified Employee Purchase Plan 1998 [Member] | Minimum [Member]
Employee stock purchase plan [Abstract]
Price Range (in dollars per share)			$ 4.62
Non-Qualified Employee Purchase Plan 1998 [Member] | Maximum [Member]
Employee stock purchase plan [Abstract]
Price Range (in dollars per share)			$ 5.65