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           Description of Stock Plans - Additional Information (Detail) 
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        6 Months Ended | 1 Months Ended | ||||||
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           Sep. 30, 2013 
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           Sep. 10, 2012
 
          Before Amendment 
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           Sep. 10, 2012
 
          After Amendment 
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           Feb. 12, 2008
 
          2007 Employee, Director and Consultant Stock Plan equity compensation plan 
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           Mar. 07, 2008
 
          2007 Employee, Director and Consultant Stock Plan equity compensation plan
 
          Any fiscal year 
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           Sep. 27, 2007
 
          2007 Employee, Director and Consultant Stock Plan equity compensation plan
 
          Maximum 
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           Sep. 30, 2013
 
          Stock Option Plan 2011 
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           May 23, 2012
 
          Stock Option Plan 2011 
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||||||
| Individual grant limits | 500,000 | |||||||
| Number of shares authorized under stock compensation plan | 4,000,000 | 20,000,000 | ||||||
| Shares reserved for future issuance | 20,000,000 | |||||||
| Number of shares available for issuance | 7,000,000 | 1,100 | 3,000,000 | 18,658,333 | ||||
| Option plan, term | 10 years | |||||||
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- Definition 
          Number Of Shares Granted Against Share Limits No definition available. 
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- Definition 
          Aggregate number of common shares reserved for future issuance. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Details 
          
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- Definition 
          The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested). Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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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. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Weighted average remaining contractual term for fully vested and expected to vest options that are exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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