Net Loss per Share - Calculation (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Numerator:
Net loss	$ (43,850)	$ (32,952)
Less: Dividends declared		(9,142)
Net loss attributable to common stockholders—basic and diluted	$ (43,850)	$ (42,094)
Denominator:
Weighted average common stock outstanding—basic and diluted (in shares)	13,160,357	3,419,720
Net loss per share—basic and diluted (in dollar per share)	$ (3.33)	$ (12.31)