Stockholders' Deficit - Summary of our Outstanding and Exercisable Warrants and Related Transactions (Details) - Warrant [Member] - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Class Of Warrant Or Right [Line Items]
Beginning balance, Warrants	6,535	1,833	3,008
Issued/granted, Warrants		4,752	75
Exercised, Warrants	(1,163)		(1,250)
Cancelled/Forfeited, Warrants		(50)
Ending balance, Warrants	5,127	6,535	1,833	3,008
Expired, Warrants	(245)
Beginning balance, Weighted Average Exercise Price	$ 1.55	$ 2.62	$ 2.78
Issued/granted, Weighted Average Exercise Price		1.19	5.63
Exercised, Weighted Average Exercise Price	0.31		3.20
Cancelled/Forfeited, Weighted Average Exercise Price		6.35
Ending balance, Weighted Average Exercise Price	1.52	$ 1.55	$ 2.62	$ 2.78
Expired, Weighted Average Exercise Price	$ 7.90
Warrants, Aggregate Intrinsic Value		$ 1,041	$ 2,448	$ 4,826
Exercised, Weighted Average Exercise Price	$ 1,146		$ 2,263
Warrants, Weighted Average Remaining Contractual Life (in Years)	8 years 3 months 18 days	7 years 3 months 18 days	2 years	1 year 7 months 6 days