Stock Based Compensation (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
Mar. 31, 2016	Mar. 31, 2015
Employees [Member]
Share-based compensation arrangement by share-based payment award, fair value assumptions and methodology [Abstract]
Estimated annualized forfeiture rate	10.00%
Non-Employees [Member]
Share-based compensation arrangement by share-based payment award, fair value assumptions and methodology [Abstract]
Estimated annualized forfeiture rate	0.00%
Employees and Directors [Member]
Share-based compensation arrangement by share-based payment award, fair value assumptions and methodology [Abstract]
Unrecognized compensation expense related to unvested stock options, granted	$ 7.1
Unrecognized compensation cost, recognized as expense over a weighted-average period	1 year 2 months 5 days
Senior Management [Member]
Share-based compensation arrangement by share-based payment award, fair value assumptions and methodology [Abstract]
Estimated annualized forfeiture rate	2.00%
Directors [Member]
Share-based compensation arrangement by share-based payment award, fair value assumptions and methodology [Abstract]
Estimated annualized forfeiture rate		0.00%
Stock Options [Member]
Share-based compensation arrangement by share-based payment award, fair value assumptions and methodology [Abstract]
Contractual term and expected life	10 years
Number of Options (Employees and Non-Employees) [Abstract]
Outstanding at beginning of period (in shares)	14,209,576
Granted (in shares)	425,000	180,000
Exercised, forfeited or expired (in shares)	(312,571)
Outstanding at end of period (in shares)	14,322,005
Exercisable at end of period (in shares)	8,942,921
Weighted-Average Exercise Price Options [Abstract]
Outstanding at beginning of period (in dollars per share)	$ 3.10
Granted (in dollars per share)	2.22
Exercised, forfeited or expired (in dollars per share)	4.10
Outstanding at end of period (in dollars per share)	3.05
Exercisable at end of period (in dollars per share)	$ 3.36
Stock Options [Member] \| Employees [Member]
Number of Options (Employees and Non-Employees) [Abstract]
Outstanding at beginning of period (in shares)	13,573,862
Granted (in shares)	425,000
Exercised, forfeited or expired (in shares)	(312,571)
Outstanding at end of period (in shares)	13,686,291
Exercisable at end of period (in shares)	8,307,207
Stock Options [Member] \| Non-Employees [Member]
Number of Options (Employees and Non-Employees) [Abstract]
Outstanding at beginning of period (in shares)	635,714
Granted (in shares)	0
Exercised, forfeited or expired (in shares)	0
Outstanding at end of period (in shares)	635,714
Exercisable at end of period (in shares)	635,714
Stock Options and Warrants [Member]
Share-based compensation arrangement by share-based payment award, fair value assumptions and methodology [Abstract]
Risk-free interest rate	1.47%	2.20%
Expected volatility	76.30%	84.30%
Expected lives		10 years
Expected dividend yield	0.00%	0.00%
Stock Options and Warrants [Member] \| Minimum [Member]
Share-based compensation arrangement by share-based payment award, fair value assumptions and methodology [Abstract]
Expected lives	5 years
Stock Options and Warrants [Member] \| Maximum [Member]
Share-based compensation arrangement by share-based payment award, fair value assumptions and methodology [Abstract]
Expected lives	10 years
Warrants [Member]
Weighted-Average Exercise Price Options [Abstract]
Number of warrants issued (in shares)	500,000
Exercise price of warrants (in dollars per share)	$ 1.74
2000 Long-Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, shares subject to stock options (in shares)	600,000
Expiration date	Aug. 06, 2010
Share-based compensation, shares available for future grant (in shares)	0
2008 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, shares subject to stock options (in shares)	13,700,000
Share-based compensation, shares available for future grant (in shares)	6,300,000

The estimated an annualized forfeiture rate for options granted to employees.

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- Definition

Contractual term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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- Definition

Refers to share-based compensation arrangements by share-based payment award, options, exercised, forfeitures, expired in period.

+ References

No definition available.

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- Definition

Refers to share-based compensation arrangements by share-based payment award, options, exercised, forfeitures, expired in period, weighted average exercise price.

+ References

No definition available.

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- Definition

Exercise price per share or per unit of warrants or rights outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(i)(4))
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Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
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Aggregate number of common shares reserved for future issuance.

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-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Unrecognized cost of unvested share-based compensation awards.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Date the equity-based award expires, in CCYY-MM-DD format.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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- References

No definition available.

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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(iii)
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- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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- Definition

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Net number of share options (or share units) granted during the period.

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- Definition

Number of options outstanding, including both vested and non-vested options.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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No definition available.

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- Definition

Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Name Staff Accounting Bulletin (SAB)
-Number Topic 14
-Section D
-Subsection 2

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