Net Loss Per Share - Reconciliation of Basic and Diluted Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Numerator:
Net loss	$ (7,761)	$ (7,168)
Less: preferred stock dividends	27	12
Net loss attributable to common stockholders	$ (7,788)	$ (7,180)
Basic and diluted net loss per share (in dollars per share)	$ (1.52)	$ (1.50)