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Stock Based Compensation - Stock Option Activity (Detail) (USD $) In Millions, except Share data in Thousands, unless otherwise specified | 12 Months Ended
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Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2011
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Shares Underlying Options, Outstanding at beginning of period | 4,065 |  |
Number of Shares Underlying Options, Granted | 1,836 | 1,024 | 1,169
Number of Shares Underlying Options, Exercised | (877) | (759) | (302)
Number of Shares Underlying Options, Forfeited | (97) |  |
Number of Shares Underlying Options, Outstanding at end of period | 4,927 | 4,065 |
Number of Shares Underlying Options, Vested - end of period | 3,459 |  |
Number of Shares Underlying Options, Vested and expected to vest - end of period | 4,854 |  |
Weighted Average Exercise Price Per Share, Outstanding at beginning of period | $ 6.12 |  |
Weighted Average Exercise Price Per Share, Granted | $ 7.55 |  |
Weighted Average Exercise Price Per Share, Exercised | $ 4.25 | $ 4.62 | $ 4.12
Weighted Average Exercise Price Per Share, Forfeited | $ 7.51 |  |
Weighted Average Exercise Price Per Share, Outstanding at end of period | $ 6.95 | $ 6.12 |
Weighted Average Exercise Price Per Share, Vested - end of period | $ 6.58 |  |
Weighted Average Exercise Price Per Share, Vested and expected to vest - end of period | $ 6.95 |  |
Weighted Average Remaining Contractual Term, Outstanding balance | 2 years 10 months 6 days | 2 years 7 months 24 days |
Weighted Average Remaining Contractual Term, Granted | 4 years 29 days |  |
Weighted Average Remaining Contractual Term, Exercised | 0 years |  |
Weighted Average Remaining Contractual Term, Forfeited | 3 years 6 months 26 days |  |
Weighted Average Remaining Contractual Term, Exercisable at end of period | 2 years 10 months 6 days | 2 years 7 months 24 days |
Weighted Average Remaining Contractual Term, Vested - end of period | 2 years 5 months 9 days |  |
Weighted Average Remaining Contractual Term, Vested and expected to vest - end of period | 2 years 10 months 6 days |  |
Aggregate Intrinsic Value, Outstanding at end of period | $ 2.81 |  |
Aggregate Intrinsic Value, Vested - end of period | 2.66 |  |
Aggregate Intrinsic Value, Vested and expected to vest - end of the period | $ 2.81 |  |

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- Definition 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. + 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 (c)(1)(iv)(3) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding. + References 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 + Details
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- Definition 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 -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(i)-(ii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Weighted average remaining contractual term for option awards outstanding, 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 -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (e)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of fully vested and expected to vest options that are exercisable. + 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 (e)(2) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The number of exercisable share options (fully vested and expected to vest) that may be converted as of the balance sheet date. + 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 (e)(2) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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