| Long Term Debt (Parenthetical) (Detail) (USD $) In Thousands, unless otherwise specified | Sep. 30, 2012 | Mar. 31, 2012 | 
|---|---|---|
| Long Term Debt Maturities Repayments Of Principal [Line Items] | ||
| Long term debt, discount | $ 242 | $ 0 | 
| Senior Secured Convertible Notes due June 21, 2013 | ||
| Long Term Debt Maturities Repayments Of Principal [Line Items] | ||
| Long term debt, discount | 0 | 1,648 | 
| Convertible Note | ||
| Long Term Debt Maturities Repayments Of Principal [Line Items] | ||
| Long term debt, discount | $ 832 | $ 0 | 
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- Definition The amount of debt discount that was originally recognized at the issuance of the instrument that has yet to be amortized. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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