Fair Value of Financial Assets and Liabilities (Tables)

9 Months Ended

Sep. 30, 2019

Fair Value Disclosures [Abstract]

Schedule of Assets and Liabilities Measured at Fair Value

The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis and indicate the level of the fair value hierarchy used to determine such fair values:

	Fair Value Measurements as of September 30, 2019 Using:
(in thousands)	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents—money market funds	$	—	$	74,883	$	—	$	74,883
	$	—	$	74,883	$	—	$	74,883
Liabilities:  None

	Fair Value Measurements as of December 31, 2018 Using:
(in thousands)	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents—money market fund	$	—	$	8,134	$	—	$	8,134
	$	—	$	8,134	$	—	$	8,134
Liabilities:
Preferred stock warrant liability	$	—	$	—	$	4,947	$	4,947
Derivative liability	—		—		201		$	201
	$	—	$	—	$	5,148	$	5,148

Summary of Aggregate Fair Values of Warrant Liability and Derivative Liability

The following table provides a roll-forward of the aggregate fair values of the Company’s warrant liability and derivative liability, for which fair values are determined using Level 3 inputs:

(in thousands)	Preferred Stock Warrant Liability		Derivative Liability
Balance as of December 31, 2018	$	4,947	$	201
Change in fair value	288		(183)
Conversion of convertible preferred stock warrant into common stock warrant in connection with Merger	(5,235)
Balance as of September 30, 2019	$	—	$	18