Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Common stock, par value (usd per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	27,093,026	26,259,254
Common stock, shares outstanding (in shares)	27,093,026	26,259,254
Series C-1 Convertible Preferred Stock [Member]
Preferred stock, par value (usd per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	11,000	11,000
Preferred stock, shares issued (in shares)	3,906	3,906
Preferred stock, shares outstanding (in shares)	3,906	3,906
Preferred stock, liquidation	$ 3,906	$ 3,906
Series F Convertible Preferred Stock [Member]
Preferred stock, par value (usd per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	10,000	10,000
Preferred stock, shares issued (in shares)	0	2,737
Preferred stock, shares outstanding (in shares)	0	2,737
Preferred stock, liquidation	$ 0	$ 2,737

Face amount or stated value per share of common stock.

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