Income Taxes (Schedule Of Reconciliation Of Statutory Federal Income Tax Rate) (Detail)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Taxes [Line Items]
Federal tax provision at statutory rate	35.00%	35.00%	35.00%
State taxes (net of Federal benefit)	10.81%	2.27%	(4.17%)
Change in tax reserve	(0.06%)	(0.94%)	(1.84%)
Orphan drug credit	0.25%	(0.70%)	(1.06%)
Stock-based compensation	1.50%	0.06%	(2.03%)
Non-deductible stock-based compensation	(1.86%)	0.20%	(0.98%)
Change in valuation allowance	(45.48%)	(29.94%)	(39.65%)
Research and development credits		7.05%	9.72%
Net proceeds from stockholder securities law settlement		(2.43%)
Other	(0.19%)	(0.53%)	0.17%
Benefit (provision) for taxes	(0.03%)	10.04%	(4.84%)

Effective Income Tax Rate Reconciliation Net Proceeds From Shareholder Securities Law Settlement

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- Definition

Effective Income Tax Rate Reconciliation Nondeductible Expense Share Based Compensation Cost Limitation

+ References

No definition available.

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- Definition

A ratio calculated by dividing the reported amount of income tax expense attributable to continuing operations for the period by GAAP-basis pretax income from continuing operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 08

-Paragraph h

-Subparagraph 2

-Article 4

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 109

-Paragraph 47

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 12

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32687-109319

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-Name Accounting Standards Codification

-Topic 740

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(h)(2))

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- Definition

The domestic federal statutory tax rate applicable under enacted tax laws to the Company's pretax income from continuing operations for the period. The "statutory" tax rate is the regular tax rate if there are alternative tax systems.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 109

-Paragraph 47

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 12

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32687-109319

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

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-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32698-109319

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 6.I)

-URI http://asc.fasb.org/extlink&oid=6889476&loc=d3e330036-122817

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- Definition

The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate attributable to changes in the valuation allowance for deferred tax assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 12

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32687-109319

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-Publisher FASB

-Name Accounting Standards Codification

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

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-Paragraph 1

-Subparagraph (SAB TOPIC 6.I)

-URI http://asc.fasb.org/extlink&oid=6889476&loc=d3e330036-122817

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- Definition

The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate attributable to nondeductible expenses under enacted tax laws, or differences in the methodologies used to determine expense amounts for financial statements prepared in accordance with generally accepted accounting principles, not otherwise listed in the existing taxonomy.

+ References

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- Definition

The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate attributable to differences in the deductibility or nondeductibility of incentive stock options and other equity-based compensation costs in accordance with generally accepted accounting principles and enacted tax laws.

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- Definition

The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate that can be explained by the state and local income tax expense or benefit, net of the federal tax benefit (expense) thereon, recorded during the period.

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- Definition

The sum of the differences between the effective income tax rate and domestic federal statutory income tax rate attributable to changes in all income tax contingencies, whether recorded or adjusted, during the period.

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The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate that can be explained by tax credits, not otherwise listed in the existing taxonomy, generated or utilized under enacted tax laws during the period.

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The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate that can be explained by research tax credits generated or utilized under enacted tax laws during the period.

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