Equity - Issue and Conversion (Details) - USD ($)			1 Months Ended	3 Months Ended
	Jul. 17, 2019	Jul. 10, 2019	Dec. 31, 2016	Mar. 31, 2020	Mar. 31, 2019	May 09, 2018
Proceeds from issuance of common stock, net of issuance costs				$ 439,000	$ 337,000
Series A Warrants
Exercise price	$ 0.33
Expiration term of warrant	5 years
Warrants issued	$ 2,100,000
Expected volatility (as a percent)	95.00%
Risk-free rate (as a percent)	1.90%
Series B Warrants
Exercise price	$ 0.33
Incremental fair value of warrants	$ 300,000
Expected volatility (as a percent)	88.00%
Risk-free rate (as a percent)	1.90%
ATM Agreement
Common stock issued (in shares)				823,452	33,995
Aggregate value of securities allowed under agreement			$ 5,000,000
Aggregate securities allowed under agreement (in shares)			10,000,000
Sale price (in dollars per shares)				$ 0.28	$ 0.34
Gross proceeds from common stock sale					$ 11,000
Commission rate (as a percent)			2.00%
Amortization of deferred cost				$ 8,000
Proceeds from issuance of common stock, net of issuance costs				$ 223,000
common shares available for issuance				8,100,000
Unamortized deferred cost				$ 129,000
LPC Program [Member]
Common stock issued (in shares)				900,000
Sale price (in dollars per shares)				$ 0.27
Amortization of deferred cost				$ 24,000
Proceeds from issuance of common stock, net of issuance costs				$ 216,000
Total cost of offering	$ 300,000
Placement agent fee (as a percent)	6.00%
common shares available for issuance				12,200,000
Unamortized deferred cost				$ 353,000
LPC Program [Member] | May 2016 Warrants
Exercise price	$ 0.75
LPC Program [Member] | Series A Warrants
Common shares issuable upon exercise	8,653,846
Exercise price	$ 0.35
Aggregate gross proceeds of warrants	$ 2,250,000
LPC Program [Member] | Series B Warrants
Common shares issuable upon exercise	4,500,000
Number of common shares which can be purchased with each warrant	1
Exercise price	$ 0.35
Commitment purchase agreement
Common stock issued (in shares)					1,213,642
Aggregate value of securities allowed under agreement						$ 10,000,000
Sale price (in dollars per shares)					$ 0.30
Amortization of deferred cost					$ 35,000
Proceeds from issuance of common stock, net of issuance costs					$ 360,000
Common Stock | LPC Program [Member]
Share Price	$ 0.26
Common stock issued (in shares)	8,653,846	8,653,846
Common Stock | Maximum | LPC Program [Member] | Series A Warrants
Common stock issued (in shares)	8,653,846