Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2019

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, 2019
	Level 1		Level 2		Level 3		Total
2017 Placement Warrants Liability	$	—	$	—	$	1,330	$	1,330
2016 Placement Warrants Liability		—		—		4,043		4,043
Total Warrant Liability	$	—	$	—	$	5,373	$	5,373

	At December 31, 2018
	Level 1		Level 2		Level 3		Total
2017 Placement Warrants Liability	$	—	$	—	$	7,115	$	7,115
2016 Placement Warrants Liability		—		—		4,729		4,729
Total Warrant Liability	$	—	$	—	$	11,844	$	11,844

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,
	2019			2018			2017
Fair value, beginning of period	$	11,844		$	22,420		$	2,723
Issuance of 2016 Placement Warrants		—			—			—
Issuance of 2017 Placement Warrants		—			—			3,373
Change in fair value of Level 3 financial liabilities		(2,496	)		(9,379	)		16,598
Fair value of 2016 Placement Warrants at exercise		(3,457	)		(1,187	)		(200	)
Fair value of 2017 Placement Warrants at exercise		(518	)		(10	)		(74	)
Fair value, end of period	$	5,373		$	11,844		$	22,420