Long Term Debt And Convertible Notes - Oxford Finance Loan Narrative (Details) - USD ($)				1 Months Ended		12 Months Ended
	Oct. 05, 2020	Feb. 20, 2020	Aug. 28, 2014	May 31, 2018	Aug. 31, 2014	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2014	May 31, 2017
Debt Instrument [Line Items]
Payments of debt fees						$ 1,875,000	$ 0	$ 0
Fees and legal expenses						196,000
Payment of fees to lender and third parties						162,000	0	0
Interest expense on deferred financing and debt issuance costs, less than						968,000	28,000	$ 36,000
Success Fee Derivative
Debt Instrument [Line Items]
Derivative liability	$ 1,900,000						$ 1,200,000
Medium-term Notes | Oxford Finance Loan
Debt Instrument [Line Items]
Debt instrument, face amount including accordion feature					$ 20,000,000.0
Proceeds from issuance of debt									$ 15,000,000.0
Accordion feature on face amount of debt					$ 5,000,000.0
Stated interest rate					8.96%
Debt term					5 years
Interest payments term					36 months
Principal and interest payments term					24 months
Final payment, percentage of loan amount due					8.50%
Incremental fee amount due at maturity										$ 100,000
Fee amount		$ 900,000		$ 800,000						$ 400,000
Effective interest rate		11.11%					11.11%	11.17%
Contingent fee amount, maximum					$ 2,500,000
Contingent fee amount						1,900,000	$ 1,900,000
Payments of debt fees	$ 1,900,000
Repayments on term loan obligations		$ 17,300,000
Extinguishment of debt		15,000,000.0
Final payment on loan		1,300,000
Accrued interest		100,000
Loss on extinguishment of debt		$ 400,000
Fees and legal expenses				$ 100,000		0	8,000
Payment of fees to lender and third parties						200,000
Interest expense on deferred financing and debt issuance costs, less than						100,000	100,000	$ 100,000
Interest expense						$ 400,000	$ 1,700,000	$ 1,700,000
Medium-term Notes | Oxford Finance Loan | 18 Months After August 28, 2014
Debt Instrument [Line Items]
Contingent fee amount, percentage of loan					6.25%
Contingent fee amount, term			18 months
Medium-term Notes | Oxford Finance Loan | Between 18 Months and 3 Years After August 28, 2014
Debt Instrument [Line Items]
Contingent fee amount, percentage of loan					8.75%
Medium-term Notes | Oxford Finance Loan | After Third Anniversary of August 28, 2014
Debt Instrument [Line Items]
Contingent fee amount, percentage of loan					12.50%
Medium-term Notes | Oxford Finance Loan | Debt Instrument, Covenant, Scenario One
Debt Instrument [Line Items]
Stated interest rate					8.71%
Medium-term Notes | Oxford Finance Loan | Debt Instrument, Covenant, Scenario Two
Debt Instrument [Line Items]
Component of annual rate calculation, percentage in addition to LIBOR rate				6.86%
Medium-term Notes | Oxford Finance Loan | Minimum | Between 18 Months and 3 Years After August 28, 2014
Debt Instrument [Line Items]
Contingent fee amount, term			18 months
Medium-term Notes | Oxford Finance Loan | Maximum | Between 18 Months and 3 Years After August 28, 2014
Debt Instrument [Line Items]
Contingent fee amount, term			3 years
Medium-term Notes | Oxford Finance Loan | London Interbank Offered Rate (LIBOR) | Debt Instrument, Covenant, Scenario Two
Debt Instrument [Line Items]
Basis spread on variable rate				1.85%