Debt - Notes Payable (Details) - USD ($)	1 Months Ended
	Oct. 31, 2019	May 31, 2019	Mar. 31, 2020	Dec. 31, 2019	Mar. 21, 2018
Notes payable
Notes payable, net of discount			$ 7,132,000	$ 6,778,000
Notes payable - current, net			400,000	450,000
Notes payable - current, net			400,000	450,000
Notes payable
Notes payable
Principal amount			7,678,000	7,228,000
Less: unamortized debt discount and net issuance costs			(146,000)
Note payable, net			7,532,000	7,228,000
Notes payable, net of discount			400,000	450,000
Notes payable - current, net			7,132,000	6,778,000
Notes payable - current, net			7,132,000	6,778,000
March 2018 note payable | Securities purchase agreement
Notes payable
Less: unamortized debt discount and net issuance costs					$ (315,000)
2019 Exchange Note 1
Notes payable
Accrued interest on notes payable		$ 411,000
Notes payable		$ 10,125,000
Interest rate (as a percent)		10.00%
2019 Exchange Note 1 | Notes payable
Notes payable
Principal amount			4,381,000	4,381,000
2019 Exchange Note 2
Notes payable
Notes payable		$ 2,297,000
Interest rate (as a percent)		10.00%
2019 Exchange Note 2 | Notes payable
Notes payable
Principal amount			2,297,000	2,297,000
Tempesta Note Payable
Notes payable
Principal amount	$ 550,000		500,000
Notes payable	$ 550,000
Interest rate (as a percent)	2.50%
Semi-annual principal and interest payments	$ 50,000
Tempesta Note Payable | Notes payable
Notes payable
Principal amount			500,000	$ 550,000
Royalty Interest | Notes payable
Notes payable
Principal amount			$ 500,000