Net Loss per Share - Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Loss per share
Net loss	$ (51,000)	$ (49,326)
Weighted average common shares outstanding, basic and diluted (in shares)	27,537,939	15,655,293
Net loss per share, basic and diluted (in dollars per share)	$ (1.85)	$ (3.15)