Warrants - PIPE Financing Warrants (Details)		1 Months Ended	6 Months Ended	12 Months Ended
	Mar. 23, 2020 USD ($)	Dec. 31, 2019 USD ($) $ / shares shares	Jun. 30, 2020 USD ($) shares	Dec. 31, 2019 USD ($) $ / shares item shares
Convertible Promissory Notes and Common Stock Warrants [Line Items]
Warrants to purchase (in shares) | shares			9,580
Aggregate purchase price of warrants		$ 3,000	$ 4,086,000	$ 3,000
Proceeds from issuance of warrants	$ 653,000
Issuance of common stock in PIPE financing, net of issuance costs of $51			$ 668,000
PIPE Financing Warrants, Dec 2019
Convertible Promissory Notes and Common Stock Warrants [Line Items]
Exercise price (in dollars per share) | $ / shares		$ 0.78		$ 0.78
Warrant exercisable period after, issuance date		6 months
Term of warrant		5 years		5 years
Proceeds from issuance of warrants				$ 1,500,000
Number of securities | item				2
Issuance of common stock in PIPE financing, net of issuance costs of $51				$ 1,035,000
Issuance of warrants		$ 686,000		$ 465,000
PIPE Financing Warrants, Dec 2019 | Maximum
Convertible Promissory Notes and Common Stock Warrants [Line Items]
Warrants to purchase (in shares) | shares		1,250,000		1,250,000
Aggregate purchase price of warrants		$ 1,500,000		$ 1,500,000
Private placement | PIPE Financing Warrants, Dec 2019
Convertible Promissory Notes and Common Stock Warrants [Line Items]
Unregistered shares issued | shares		2,500,000
Stock price | PIPE Financing Warrants, Dec 2019
Convertible Promissory Notes and Common Stock Warrants [Line Items]
Warrant liability | $ / shares		0.62		0.62
Strike price | PIPE Financing Warrants, Dec 2019
Convertible Promissory Notes and Common Stock Warrants [Line Items]
Warrant liability | $ / shares		0.78		0.78
Expected life | PIPE Financing Warrants, Dec 2019
Convertible Promissory Notes and Common Stock Warrants [Line Items]
Warrant liability		5		5
Volatility | PIPE Financing Warrants, Dec 2019
Convertible Promissory Notes and Common Stock Warrants [Line Items]
Warrant liability		143		143
Risk free rate | PIPE Financing Warrants, Dec 2019
Convertible Promissory Notes and Common Stock Warrants [Line Items]
Warrant liability		2.42		2.42