Notes Payable, Interest rates on Leviston and Five Institutions' Notes, Conversion Option, and Loss on Issuance (Details) $ / shares in Units, $ in Thousands			12 Months Ended
	Aug. 31, 2021	Apr. 20, 2021 USD ($)	Dec. 31, 2021 USD ($) d $ / shares	Dec. 31, 2020 USD ($) $ / shares	Sep. 30, 2021 USD ($)	May 31, 2021 USD ($)	Apr. 30, 2021 USD ($)	Dec. 31, 2019 $ / shares
Conversion Option [Abstract]
Warrant exercise price (in dollars per share) | $ / shares			$ 0.20	$ 0.19				$ 0.11
Proceeds from, promissory note disbursement			$ 940	$ 13,347
Leviston Notes [Member]
Conversion Option [Abstract]
Default interest rate	15.00%
Proceeds from, promissory note disbursement		$ 250
Five Institutions' Notes [Member]
Conversion Option [Abstract]
Proceeds from, issuance of one-time aggregate amount			$ 56
Percentage of outstanding principal			5.00%
Five Institutions' Notes [Member] | Minimum [Member]
Conversion Option [Abstract]
Conversion price (in dollars per share) | $ / shares			$ 0.01
Leviston Disbursements and Five Institutions' Notes [Member]
Conversion Option [Abstract]
Promissory note disbursement, interest rate			5.00%
Default interest rate			15.00%
Common stock conversion volume-weighted price percentage			75.00%
Number of trading days | d			10
Fair value of convertible notes					$ 1,400	$ 1,400	$ 1,400
Loss on issuance					$ 1,100	$ 1,100	$ 1,400
Promissory note maturity term			12 months
Warrant exercise price (in dollars per share) | $ / shares			$ 0.18
Common stock conversion price percentage			90.00%