Debt - Securities Purchase Agreement (Details)						1 Months Ended		3 Months Ended				6 Months Ended		12 Months Ended
	Apr. 17, 2019 USD ($)	Aug. 02, 2018 USD ($)	Mar. 21, 2018 USD ($)	Feb. 26, 2018 USD ($)	Dec. 08, 2017 USD ($)	Apr. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($) NotesSeries item	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2018 USD ($) NotesSeries	Dec. 31, 2019 USD ($)	Dec. 31, 2016 USD ($)
Debt
Principal amount																$ 12,500,000
Proceeds from issuance of notes payable, net of issuance costs and debt discount												$ 350,000	$ 5,050,000
Number of notes for which standstill fee paid | NotesSeries											4
Maximum aggregate redemption amount		$ 500,000
Standstill fee											$ 199,000			$ 63,296
Increase in principal balance of notes payable											119,000			37,296
Standstill fee paid in cash											80,000			26,000
Loss on extinguishment of debt									$ (2,663,000)				(4,605,000)
Change in warrant liability								$ 386,000	$ (207,000)			387,000	$ (161,000)
Chicago Venture Partners, L.P.
Debt
Total standstill fee											$ 499,000			$ 499,403
Number of notes for which standstill fee paid											4			4
Securities purchase agreement | Chicago Venture Partners, L.P.
Debt
Principal amount			$ 1,090,000
Securities purchase agreement | Promissory Note, December 08, 2017 | Chicago Venture Partners, L.P.
Debt
Principal amount					$ 1,588,000
Aggregate purchase price					1,100,000
Original issue discount					462,500
Transaction expenses					$ 25,000
Interest rate (as a percent)					8.00%
Convertible debt payable								$ 0				$ 0			$ 0
Maximum aggregate redemption amount		$ 500,000
Standstill fee											$ 142,000
Increase in principal balance of notes payable											86,000
Repayments of notes payable, principal							$ 811,000
Repayments of notes payable, interest							179,000
Loss on extinguishment of debt	$ 19,494					$ 100,148	243,000
Securities purchase agreement | February 2018 note payable | Chicago Venture Partners, L.P.
Debt
Principal amount				$ 2,241,000
Proceeds from issuance of notes payable, net of issuance costs and debt discount				1,560,000
Original issue discount				656,000
Transaction expenses				$ 25,000
Interest rate (as a percent)				8.00%
Convertible Notes Payable Gross											0			$ 0	0
Principal less discount											0			$ 0	$ 0
Repayments of notes payable, principal							2,045,000
Repayments of notes payable, interest							204,000
Loss on extinguishment of debt						$ 37,740	$ 488,000				102,000
Securities purchase agreement | March 2018 note payable
Debt
Discounts			315,000
Securities purchase agreement | March 2018 note payable | Chicago Venture Partners, L.P.
Debt
Aggregate purchase price			750,000
Transaction expenses			$ 25,000
Interest rate (as a percent)			8.00%
Standstill fee											96,000
Increase in principal balance of notes payable											58,000
Standstill fee paid in cash											38,000
Repayments of notes payable, principal										$ 1,050,000
Repayments of notes payable, interest										86,000
Loss on extinguishment of debt										$ 1,211,000	$ 224,000