Debt (Tables)

9 Months Ended

Sep. 30, 2021

Debt Disclosure [Abstract]

Summary of Debt Obligations

The following table sets forth our various debt obligations:

	September 30, 2021		December 31, 2020
Series A Note (principal amount)	$	—	$	2,481
Series B Note (principal amount)	—		3,585
Paycheck Protection Program Loan	—		2,850
Convertible notes	222		250
Promissory notes	905		905
Total debt	$	1,127	$	10,071
Debt discount - warrants (2020 Convertible Notes)	—		(1,029)
Debt discount - issuance costs (2020 Convertible Notes)	—		(650)
Less: current maturities of long-term debt	(83)		(4,435)
Less: related-party debt	(195)		(195)
Long-term debt	$	849	$	3,762

Summary of Calculated Aggregate Fair Values and Assumptions

The following table sets forth the assumptions used to calculate the fair value of our warrant liability at the respective dates:

	September 30, 2021			December 31, 2020
Strike price per share	$	2.25		$	4.00
Closing price per share	$	0.93		$	1.26
Term (years)	1.78			2.53
Volatility	142		%	146		%
Risk-free rate	0.17		%	0.17		%
Dividend Yield	—			—

Summary of Interest Expense

The following table sets forth interest expense for our various debt obligations included on the condensed consolidated statements of operations:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
2020 Convertible Notes	$	—	$	279	$	1,111	$	279
Accretion of debt discount - issuance costs	—		185		1,741		370
Accretion of debt discount - warrants	—		805		1,029		805
All other debt and financing obligations	(7)		93		176		469
Total	$	(7)	$	1,362	$	4,057	$	1,923