Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2021

Fair Value Disclosures [Abstract]

Schedule of Fair Value of Financial Liabilities

The following table sets forth the fair value of the Company’s financial liabilities by level within the fair value hierarchy (in thousands):

	At December 31, 2021
	Level 1		Level 2		Level 3		Total
2017 Placement Warrants Liability	$	—	$	—	$	5,030	$	5,030
2016 Placement Warrants Liability	—		—		1,765		1,765
Total Warrant Liability	$	—	$	—	$	6,795	$	6,795

	At December 31, 2020
	Level 1		Level 2		Level 3		Total
2017 Placement Warrants Liability	$	—	$	—	$	3,675	$	3,675
2016 Placement Warrants Liability	—		—		1,189		1,189
Total Warrant Liability	$	—	$	—	$	4,864	$	4,864

Summary of Changes in Fair Value of Level 3 Financial Liabilities

The following table summarizes the changes in the fair value of the Company’s Level 3 financial liabilities (in thousands):

	Year Ended December 31,
	2021		2020		2019
Fair value, beginning of period	$	4,864	$	5,373	$	11,844
Change in fair value of Level 3 financial liabilities	2,284		(509)		(2,496)
Fair value of 2016 Placement Warrants at exercise	(2)		—		(3,457)
Fair value of 2017 Placement Warrants at exercise	(351)		—		(518)
Fair value, end of period	$	6,795	$	4,864	$	5,373