Assets and Liabilities Measured at Fair Value (Details) (USD $)
Share data in Millions, unless otherwise specified |
3 Months Ended | 6 Months Ended | 12 Months Ended | 137 Months Ended | |||
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Jun. 30, 2013
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Jun. 30, 2012
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Jun. 30, 2013
item
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Jun. 30, 2012
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Dec. 31, 2012
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Jun. 30, 2013
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Dec. 31, 2011
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Assets and Liabilities Measured at Fair Value | |||||||
Transfer of assets from Level 1 to Level 2 | $ 0 | $ 0 | $ 0 | ||||
Transfer of assets from Level 2 to Level 1 | 0 | 0 | 0 | ||||
Proceeds from issuance of warrants | 3,300,000 | ||||||
Number of inputs used in fair value classification | 6 | ||||||
Warrants exercised (in shares) | 0.5 | ||||||
Change in fair value of warrant liability | (619,000) | 118,000 | (357,000) | 2,494,000 | (1,910,000) | ||
Weighted average assumptions used in the Black-Scholes valuation model for the warrants | |||||||
Expected stock price volatility (as a percent) | 111.44% | 73.27% | |||||
Risk free interest rate (as a percent) | 0.11% | 0.29% | |||||
Expected life of warrants | 8 months 1 day | 1 year 8 months 1 day | |||||
Expected annual dividend per share (as a percent) | 0.00% | 0.00% | |||||
Assets: | |||||||
Cash/Money market fund | 23,476,000 | 28,858,000 | 23,476,000 | 28,858,000 | 33,971,000 | 23,476,000 | 25,668,000 |
Level 1
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Assets: | |||||||
Cash/Money market fund | 23,476,000 | 23,476,000 | 33,971,000 | 23,476,000 | |||
Fair value of assets | 23,476,000 | 23,476,000 | 33,971,000 | 23,476,000 | |||
Level 2
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Assets: | |||||||
Fair value of assets | 50,700,000 | 50,700,000 | 65,151,000 | 50,700,000 | |||
Liabilities: | |||||||
Secured debt | 498,000 | 498,000 | 697,000 | 498,000 | |||
Fair value of liabilities | 498,000 | 498,000 | 697,000 | 498,000 | |||
Level 2 | Corporate debt securities
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Assets: | |||||||
Fair value of assets | 29,604,000 | 29,604,000 | 42,497,000 | 29,604,000 | |||
Level 2 | Commercial paper
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Assets: | |||||||
Fair value of assets | 20,746,000 | 20,746,000 | 19,744,000 | 20,746,000 | |||
Level 2 | Certificate of deposit
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Assets: | |||||||
Fair value of assets | 350,000 | 350,000 | 2,910,000 | 350,000 | |||
Level 3
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Liabilities: | |||||||
Warrant liability | 551,000 | 551,000 | 908,000 | 551,000 | |||
Fair value of liabilities | 551,000 | 551,000 | 908,000 | 551,000 | |||
Increase/(Decrease) in fair value | (600,000) | (100,000) | (400,000) | (2,500,000) | |||
Total
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Assets: | |||||||
Cash/Money market fund | 23,476,000 | 23,476,000 | 33,971,000 | 23,476,000 | |||
Fair value of assets | 74,176,000 | 74,176,000 | 99,122,000 | 74,176,000 | |||
Liabilities: | |||||||
Secured debt | 498,000 | 498,000 | 697,000 | 498,000 | |||
Warrant liability | 551,000 | 551,000 | 908,000 | 551,000 | |||
Fair value of liabilities | 1,049,000 | 1,049,000 | 1,605,000 | 1,049,000 | |||
Total | Corporate debt securities
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Assets: | |||||||
Fair value of assets | 29,604,000 | 29,604,000 | 42,497,000 | 29,604,000 | |||
Total | Commercial paper
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Assets: | |||||||
Fair value of assets | 20,746,000 | 20,746,000 | 19,744,000 | 20,746,000 | |||
Total | Certificate of deposit
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Assets: | |||||||
Fair value of assets | $ 350,000 | $ 350,000 | $ 2,910,000 | $ 350,000 |