Description of Business - Additional Information (Details) - USD ($) $ in Thousands |
Dec. 31, 2015 |
Dec. 31, 2014 |
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| Description Of Business [Abstract] | ||
| Accumulated deficit | $ (1,140,083) | $ (1,119,477) |
| Cash, cash equivalents and marketable securities | $ 66,300 |
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- Definition The cumulative amount of the reporting entity's undistributed earnings or deficit. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Cash and cash equivalents and marketable securities. No definition available.
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- Definition Description Of Business [Abstract] No definition available.
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