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Warrants | 6 Months Ended
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Jun. 30, 2019
Debt Disclosure [Abstract] |
Warrants | Warrants We issued 992 thousand warrants in connection with a private placement of our common stock in April 2012. Each warrant gives the holder thereof the right to purchase one share of common stock at an exercise price equal to $10.00. The warrants were issued with an aggregate fair value of $5.1 million. During the six months ended June 30, 2019, 260 thousand warrants were exercised resulting in the issuance of 168 thousand common shares. Upon exercise, we reclassified approximately $4.8 million of warrant fair value from warrant liability to additional paid-in capital, of which $2.3 million related to changes in fair value during the six months ended June 30, 2019. During the six months ended June 30, 2018, 63 thousand warrants were exercised resulting in the issuance of 29 thousand common shares. Upon exercise, we reclassified approximately $0.6 million of warrant fair value from warrant liability to additional paid-in capital, of which $42 thousand related to changes in fair value during the six months ended June 30, 2018. We account for these warrants to purchase our common shares in accordance with ASC 470-20, Debt with Conversion and Other Options and ASC 815-40, Derivatives and Hedging - Contracts in Entity's Own Equity.

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