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Income Taxes - Additional Information (Detail) (USD $) | 12 Months Ended
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Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2011
Income Taxes Disclosure [Line Items] |  |  |
Provision for federal or state income taxes | $ 0 | $ 0 | $ 0
Net operating loss carryforwards expiration start year | 2023 |  |
Net operating loss carryforwards expiration ending year | 2033 |  |
Federal Tax credit expiration start year | 2020 |  |
Federal Tax credit expiration ending year | 2033 |  |
Net operating loss | 8,500,000 |  |
Net operating losses limited for year minimum | 2014 |  |
Net operating losses limited for year maximum | 2027 |  |
Remaining portion of net operating losses | 96,300,000 |  |
Net operating losses, recognized as a benefit through additional-paid-in-capital | 1,800,000 |  |
Gross unrecognized tax benefits | 0 | 1,100,000 |
Unrecognized interest or penalties | 0 | 0 | 0
Income tax examination year subject to examination, Range start | 2001 |  |
Income tax examination year subject to examination, Range End | 2012 |  |
Minimum [Member] |  |  |
Income Taxes Disclosure [Line Items] |  |  |
Net operating losses limited for use utilized on an annual basis | 200,000 |  |
Maximum [Member] |  |  |
Income Taxes Disclosure [Line Items] |  |  |
Net operating losses limited for use utilized on an annual basis | 1,400,000 |  |
U.S. Federal Government [Member] |  |  |
Income Taxes Disclosure [Line Items] |  |  |
Net operating loss carryforwards | 104,800,000 |  |
US Federal Tax credits carry forward | 23,700,000 |  |
State and Local Jurisdiction [Member] |  |  |
Income Taxes Disclosure [Line Items] |  |  |
Net operating loss carryforwards | $ 60,300,000 |  |

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