Selected Quarterly Financial Data (Tables)

12 Months Ended

Dec. 31, 2018

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Information [Table Text Block]

	Quarter Ended
	March 31, 2018			June 30, 2018			September 30, 2018			December 31, 2018
Loss from operations	$	(4,990	)	$	(5,003	)	$	(4,320	)	$	(3,258	)
Net (loss)	$	(2,326	)	$	(4,214	)	$	(3,689	)	$	(3,193	)
Net loss per share – basic	$	(0.70	)	$	(1.05	)	$	(0.93	)	$	(1.12	)
Net loss per share – dilutive	$	(0.70	)	$	(1.05	)	$	(0.93	)	$	(1.12	)
Weighted average common share – basic		3,673,340			3,683,384			4,028,304			13,442,104
Weighted average common share – dilutive		3,673,340			3,683,384			4,028,304			13,442,104

	Quarter Ended
	March 31, 2017			June 30, 2017			September 30, 2017			December 31, 2017*
Loss from operations	$	(8,149	)	$	(6,475	)	$	(5,842	)	$	(5,783	)
Net (loss) income	$	(3,058	)	$	(4,315	)	$	(10,930	)	$	2,812
Net (loss) income per share – basic	$	(0.70	)	$	(1.05	)	$	(4.90	)	$	0.76
Net (loss) income per share – dilutive	$	(0.70	)	$	(1.05	)	$	(4.90	)	$	0.76
Weighted average common share – basic		3,355,636			3,514,435			3,665,134			3,673,340
Weighted average common share – dilutive		3,355,636			3,514,435			3,665,134			3,673,340

*Net Income due to gain on remeasurement of the warrant liabilities in excess of the quarter to date loss.