Stock Option Activity (Detail) (USD $)	12 Months Ended
Dec. 31, 2014
Number of Shares
Options outstanding, January 1, 2014	10,379,668
Granted	1,983,420
Forfeited	(1,529,855)
Exercised	(685,146)
Options outstanding, December 31, 2014	10,148,087
Weighted Average Exercise Price Per Share
Options outstanding, January 1, 2014	$ 10.83
Granted	$ 6.94
Forfeited	$ 13.54
Exercised	$ 4.44
Options outstanding, December 31, 2014	$ 10.09

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.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iv)(3)

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

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

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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- Definition

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

+ References

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-Publisher FASB

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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 that were terminated.

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

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

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