Fair Value Measurement (Tables)

6 Months Ended

Jun. 30, 2020

Fair Value Disclosures [Abstract]

Schedule of Fair Value Assets And Liabilities Measured On Recurring Basis

	June 30, 2020
	Level 1		Level 2		Level 3		Total
	(in thousands)
Assets:
Money market funds	$	80,045	$	—	$	—	$	80,045
Total assets	$	80,045	$	—	$	—	$	80,045

	December 31, 2019
	Level 1		Level 2		Level 3		Total
	(in thousands)
Assets:
Money market funds	$	4,003	$	—	$	—	$	4,003
Total assets	$	4,003	$	—	$	—	$	4,003
Liabilities:
Series B preferred stock tranche right liability	$	—	$	—	$	300	$	300
Total liabilities	$	—	$	—	$	300	$	300

Schedule of Aggregate Fair Value of The Company's Series B Preferred Stock Tranche Right Liability

The following table provides a roll-forward of the aggregate fair value of the Company’s series B preferred stock tranche right liability, for which fair value is determined using Level 3 inputs:

	Series B Preferred Stock Tranche Right Liability
	(in thousands)
Balance as of December 31, 2019	$	300
Exercise of series B preferred stock tranche right		(300	)
Balance as of June 30, 2020	$	—

Schedule of Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation

The following table presents a roll-forward of the aggregate fair values of the Company’s convertible loan notes (Note 5) for which fair value is determined by Level 3 inputs:

	Convertible Loan Notes
	(in thousands)
Balance as of December 31, 2019
Initial fair value	$	10,000
Change in fair value plus accrued interest		83
Settlement of convertible loan notes		(10,083	)
Balance as of June 30, 2020	$	—