Activity under Stock Based Compensation Plans (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	6 Months Ended
Jun. 30, 2012
Options and Awards Available for Grant
Beginning balance	11,524
Options granted	(3,612)
Awards granted	(1,815)
Options exercised	824
Awards vested	40
Options forfeited (unvested)	310
Options expired (vested)	4
Awards cancelled (unvested)	40
Ending balance	6,411
Number of share outstanding beginning balance	11,101
Options granted	3,612
Awards granted	1,815
Options exercised	(824)
Awards vested	(40)
Options forfeited (unvested)	(310)
Options expired (vested)	(4)
Awards cancelled (unvested)	(40)
Number of share outstanding ending balance	15,310
Weighted-Average Price Per Share
Beginning balance	$ 3.09
Options granted	$ 3.66
Awards granted	$ 4.23
Options exercised	$ 1.70
Awards vested	$ 4.22
Options forfeited (unvested)	$ 3.24
Options expired (vested)	$ 4.55
Awards cancelled (unvested)	$ 4.22
Ending balance	$ 3.42

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Share Based Compensation Arrangement by Share Based Payment Award Options and Equity Instruments Other Than Options Nonvested Weighted Average Price

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- Definition

Share Based Compensation Arrangement by Share Based Payment Award, Options and Nonvested Options, Outstanding, Number

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No definition available.

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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- Definition

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

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-Subparagraph (c)(2)(iii)(1)

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-Paragraph A240

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- Definition

The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

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-Publisher FASB

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-Paragraph A240

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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- Definition

For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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

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- Definition

Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options of the plan that expired.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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Weighted average price at which grantees can acquire the shares reserved for issuance on stock options awarded.

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Number of share options (or share units) exercised during the current period.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

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