Fair Value of Financial Instruments (Tables)

9 Months Ended

Sep. 30, 2018

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 September 30, 2018
	Level 1		Level 2		Level 3		Total
2017 Placement Warrants Liability	$	—	$	—	$	12,400	$	12,400
2016 Placement Warrants Liability		—		—		9,562		9,562
Total	$	—	$	—	$	21,962	$	21,962

	At December 31, 2017
	Level 1		Level 2		Level 3		Total
2017 Placement Warrants Liability	$	—	$	—	$	12,487	$	12,487
2016 Placement Warrants Liability		—		—		9,933		9,933
Total	$	—	$	—	$	22,420	$	22,420

Summary of Changes in Fair Value of Level 3 Financial Liabilities

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

	Nine Months Ended September 30,
	2018			2017
Fair value, beginning of period	$	22,420		$	2,723
Issuance of 2017 Placement Warrants		—			3,373
Fair value of common stock warrants reclassified from liability to additional paid-in capital upon exercise		(342	)		—
Change in fair value of Level 3 financial liabilities		(116	)		6,739
Fair value, end of period	$	21,962		$	12,835