Changes in Warrant Liabilities (Detail) (USD $)
|
1 Months Ended | 3 Months Ended | 12 Months Ended |
---|---|---|---|
May 21, 2008
|
Jun. 30, 2008
|
Dec. 31, 2011
|
|
Warranty Liability [Line Items] | |||
Beginning Balance | $ 861,000 | ||
Change in fair value of warrant liabilities | 100,000 | 356,000 | 524,000 |
Intrinsic value of liability warrants exercised | $ (1,385) |