Fair Value of Financial Instruments (Tables)

3 Months Ended

Mar. 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 March 31, 2019
	Level 1		Level 2		Level 3		Total
2017 Placement Warrants Liability	$	—	$	—	$	8,955	$	8,955
2016 Placement Warrants Liability		—		—		5,917		5,917
Total	$	—	$	—	$	14,872	$	14,872

	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	$	—	$	—	$	11,844	$	11,844

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):

	Three Months Ended March 31,
	2019			2018
Fair value, beginning of period	$	11,844		$	22,420
Change in fair value of Level 3 financial liabilities		3,120			(8,182	)
Fair value of 2016 Placement Warrants at exercise		(66	)		—
Fair value of 2017 Placement Warrants at exercise		(26	)		—
Fair value, end of period	$	14,872		$	14,238