Equity - Issue and Conversion (Details) - USD ($)							1 Months Ended	12 Months Ended
	Jul. 21, 2020	Apr. 22, 2020	Apr. 20, 2020	Apr. 09, 2020	Jul. 17, 2019	May 09, 2018	Dec. 31, 2016	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Proceeds from issuance of common stock, net of issuance costs								$ 2,714,000	$ 14,599,000
Exercise price								$ 0.34	$ 0.38	$ 0.39
Unamortized deferred cost								$ 353,000
Warrants Series A and B
Exercise price			$ 0.24
Warrants issued			$ 1,900,000
Expected volatility (as a percent)			95.00%
Risk-free rate (as a percent)			0.41%
Series B Warrants
Warrants Exercise Period					6 months
Private Placement [Member]
Total cost of offering			$ 334,000
Gross proceeds from common stock sale									$ 2,600,000
Placement agent fee (as a percent)			6.00%
Private Placement [Member] | Warrants Series A and B
Share Price			$ 0.30
Aggregate gross proceeds of warrants			$ 3,000,000.0
Private Placement [Member] | Series A Warrants
Gross proceeds from common stock sale								400,000
Private Placement [Member] | Series B Warrants
Exercise price		$ 0.26
ATM Agreement
Proceeds from issuance of common stock, net of issuance costs								$ 1,800,000	$ 223,000
Stock Issued During period Shares New Issues (in shares)								1,856,960	823,452
Aggregate value of securities allowed under agreement							$ 5,000,000.0
Sale price (in dollars per shares)								$ 0.97	$ 0.28
Amortization of deferred cost								$ 57,000	$ 8,000
Unamortized deferred cost								$ 70,000	$ 127,000
Aggregate securities allowed under agreement (in shares)							10,000,000
Commission rate (as a percent)							2.00%
common shares available for issuance								2,200,000
LPC Program
Stock Issued During period Shares New Issues (in shares)									900,000
Share Price									$ 0.27
Gross proceeds from common stock sale									$ 216,000
Amortization of deferred cost									24,000
Unamortized deferred cost								$ 353,000	$ 352,000
Commitment purchase agreement
Common shares issuable upon exercise						3,153,808
Exercise price						$ 0.4122
Gross proceeds from common stock sale						$ 1,300,000
Aggregate value of securities allowed under agreement						$ 10,000,000.0
Firm Commitment Offering
Number of shares to purchase in agreement	17,857,143
Purchase price	$ 0.42
Percentage of underwriting discount	6.00%
Total cost of offering	$ 155,000
Proceeds from issuance of common stock, net of issuance costs	$ 8,000,000.0
Over-Allotment Option
Number of shares to purchase in agreement	2,678,571
Minimum [Member] | Private Placement [Member]
Warrants Exercise Period		6 months
Maximum [Member] | Private Placement [Member]
Warrants Exercise Period		5 years
Common Stock [Member] | Private Placement [Member]
Stock Issued During period Shares New Issues (in shares)			15,000,000						15,000,000
Share Price			$ 0.20
Common shares issuable upon exercise			11,250,000
Common Stock [Member] | Private Placement [Member] | Series A Warrants
Common shares issuable upon exercise			7,500,000
Common Stock [Member] | Private Placement [Member] | Series B Warrants
Common shares issuable upon exercise			3,750,000
Common Stock [Member] | Subscription Agreement
Stock Issued During period Shares New Issues (in shares)									4,719,207
Common Stock [Member] | Firm Commitment Offering
Stock Issued During period Shares New Issues (in shares)									20,535,714
Barrick | Subscription Agreement
Number of shares to purchase in agreement				4,719,207
Purchase price				$ 0.2119
Proceeds from issuance of common stock, net of issuance costs				$ 900,000