Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2021

Fair Value Disclosures [Abstract]

Assets Measured or Disclosed at Fair Value on Recurring Basis

Assets measured or disclosed at fair value on a recurring basis as of December 31, 2021 and 2020 are summarized below:

	Fair Value Measurements Using
	Level 1		Level 2		Level 3		Total
	(in thousands)
December 31, 2021
Assets:
Cash and cash equivalents	$	149,800	—		—		$	149,800
	$	149,800	$	—	$	—	$	149,800
Liabilities:
Derivative liability	—		—		$	1,820	$	1,820
	$	—	$	—	$	1,820	$	1,820

	Fair Value Measurements Using
	Level 1		Level 2		Level 3		Total
	(in thousands)
December 31, 2020
Assets:
Cash and cash equivalents	$	228,698	—		—		$	228,698
U.S. government debt securities	—		39,992		—		39,992
	$	228,698	$	39,992	$	—	$	268,690
Liabilities:
Derivative liability	—		—		$	2,420	$	2,420
	$	—	$	—	$	2,420	$	2,420

Activity of Fair Value Derivative Liability

The following table provides a roll-forward of the fair value of the derivative liability (in thousands):

Balance at December 31, 2020	$	2,420
Change in fair value of derivative liability, recorded as other income	(600)
Balance at December 31, 2021	$	1,820