Condensed Consolidated Balance Sheets (unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Property and equipment, accumulated depreciation (in dollars)	$ 2,020	$ 1,919
Debt discount (in dollars)	$ 18,003	$ 18,003
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (shares)	5,000,000	5,000,000
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (shares)	150,000,000	150,000,000
Common stock, shares issued (shares)	28,356,351	25,940,247
Common stock, shares outstanding (shares)	28,356,351	25,940,247
Series A Convertible Preferred Stock
Preferred stock, shares authorized (shares)	8,000	8,000
Preferred stock, shares issued (shares)	8,000	8,000
Preferred stock, shares outstanding (shares)	8,000	8,000
Preferred stock, liquidation preference	$ 8,346