Summary of Significant Accounting Policies - Reconciliation of Basic and Diluted Income (Loss) per Share (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020		Dec. 31, 2019
Numerator:
Net loss	$ 65	$ (1,165)	$ (4,340)	$ (541)	$ (1,308)	$ (946)	$ (2,254)	$ (2,865)	$ (5,981)		$ (7,373)
Denominator:
Basic and diluted (in shares)					2,480	2,474	2,467	2,425	3,270	[1]	2,462	[1]

[1]       *Shares outstanding for prior periods have been restated for the 1-for-5 reverse stock split effective June 11, 2020.