Net Loss Per Share - Computation of Basic and Diluted Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Numerator:
Net loss	$ (2,085)	$ (3,385)	$ (3,129)	$ (640)	$ (875)	$ (598)	$ (8,598)	$ (2,113)
Less: preferred stock dividends	(4)			(4)			(12)	(23)
Net loss attributable to common stockholders	$ (2,089)			$ (644)			$ (8,610)	$ (2,136)
Denominator:
Weighted-average number of shares of common stock for diluted net loss per share (in shares)	5,257			5,184			5,237	5,128
Basic and diluted net loss per share (in dollars per share)	$ (0.40)			$ (0.12)			$ (1.64)	$ (0.42)