Fair Value Measurements - Summary of changes in fair value of the Company's warrant liability measured at fair value using significant unobservable inputs (Leve3) (Details) - Warrant [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Beginning balance	$ 8	$ 24
Additions	0	0
Change in fair value	0	(19)
Ending balance	$ 8	$ 5