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Contractual interest rate for funds borrowed, under the debt agreement.

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Debt - Schedule of Debt (Details) - USD ($)	Mar. 31, 2022	Dec. 31, 2021	Feb. 28, 2021	Nov. 30, 2019	Feb. 28, 2014
Convertible Debt
Debt Instrument [Line Items]
Net carrying value of all Notes	$ 54,271,000	$ 54,160,000
Secured Debt
Debt Instrument [Line Items]
Interest rate on notes	4.00%
Principal amount	$ 10,000,000	10,000,000
End of term fee accretion	133,000	79,000
Unamortized debt issuance cost	(27,000)	(30,000)
Net carrying value of all Notes	10,106,000	10,049,000
Line of Credit \| Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit outstanding	0	6,838,000
2014 Notes \| Convertible Debt
Debt Instrument [Line Items]
Interest rate on notes					2.75%
Principal amount	578,000	578,000	$ 500,000	$ 1,100,000
Unamortized debt discount	(8,000)	(8,000)
Unamortized debt issuance cost	(2,000)	(2,000)
Net carrying value of all Notes	568,000	568,000
2019 Notes \| Convertible Debt
Debt Instrument [Line Items]
Interest rate on notes				5.25%
Principal amount	55,000,000	55,000,000
Unamortized debt issuance cost	(1,297,000)	(1,408,000)
Net carrying value of all Notes	$ 53,703,000	$ 53,592,000