Common Stock - Earnings per share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Net loss	$ (25,659)	$ (14,212)
Weighted-average shares used to compute basic and diluted net loss per share (in shares)	16,418	15,955
Net loss per share, basic and diluted (in dollars per share)	$ (1.56)	$ (0.89)