| Assets and Liabilities that are Required to be Presented on Balance Sheet at Fair Value (Detail) (Warrant, USD $) In Thousands, unless otherwise specified | Sep. 30, 2012 | May 31, 2012 | Mar. 31, 2012 | 
|---|---|---|---|
| Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | |||
| Warrant derivative liabilities | $ 0 | $ 473 | $ 452 | 
| Fair Value, Inputs, Level 2 | |||
| Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | |||
| Warrant derivative liabilities | $ 452 | 
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- Definition Derivative instrument obligations meeting the definition of a liability which the Company is a party to as of the balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Details 
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