Basis of Presentation (Details) $ in Thousands		3 Months Ended
Feb. 08, 2019	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)
Basis of Presentation
Cash, cash equivalents and marketable securities		$ 85,100
Net loss		(17,239)	$ (118,132)
Net cash used in operations		$ 13,233	$ 28,022
Reverse stock split	0.067

Sum of investments and unrestricted cash as of the balance sheet date.

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Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities; of income (loss) available to common shareholders.

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Ratio applied to the conversion of stock split, for example but not limited to, one share converted to two or two shares converted to one.

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