Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2020

Fair Value Disclosures [Abstract]

Schedule of financial instruments carried at fair value

The following tables set forth the Company’s financial instruments carried at fair value using the lowest level of input that is significant to each financial instrument as of March 31, 2020 and December 31, 2019 (in thousands):

	March 31, 2020
	Quoted Prices in Active Markets for Identical Items (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Assets:
Money market funds	$	239,753	$	—	$	—	$	239,753
Corporate obligations	—		101,130		—		101,130
U.S. Treasury securities	—		36,691		—		36,691
Certificates of deposit	—		248		—		248
Mortgage and other asset backed securities	—		8,002		—		8,002
Total assets	$	239,753	$	146,071	$	—	$	385,824
Liabilities:
Warrants to purchase common stock	$	—	$	—	$	3,304	$	3,304
Total liabilities	$	—	$	—	$	3,304	$	3,304

 

	December 31, 2019
	Quoted Prices in Active Markets for Identical Items (Level 1)		Significant other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Assets:
Money market funds	$	193,867	$	—	$	—	$	193,867
Corporate obligations	—		138,369		—		138,369
U.S. Treasury securities	—		83,819		—		83,819
Certificates of deposit	—		493		—		493
Mortgage and other asset backed securities	—		12,470		—		12,470
Total assets	$	193,867	$	235,151	$	—	$	429,018
Liabilities:
Warrants to purchase common stock	$	—	$	—	$	1,856	$	1,856
Total liabilities	$	—	$	—	$	1,856	$	1,856

Summary of changes in the fair value of the preferred and common stock warrant liability

The following table sets forth a summary of changes in the fair value of the Company’s common stock warrant liabilities, which represent a recurring measurement that is classified within Level 3 of the fair value hierarchy, wherein fair value is estimated using significant unobservable inputs (in thousands):

	Three Months Ended March 31,
	2020		2019
Beginning balance	$	1,856	$	1,491
Change in fair value	1,448		116
Ending balance	$	3,304	$	1,607