Financial Instruments and Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2020

Fair Value Disclosures [Abstract]

Schedule of Financial Assets and Liabilities Measured at Fair Value

As of September 30, 2020, our cash equivalent investments consisted of money market funds with a fair value of $213.3 million, which are valued using level 1 inputs. The following table summarizes the Company’s financial assets and liabilities measured at fair value on a recurring basis by level within the fair value hierarchy as of December 31, 2019:

	December 31, 2019
	Level 1		Level 2		Level 3		Total
	(in thousands)
Assets:
U.S. Treasury securities	$	43,245	$	—	$	—	$	43,245
Money market funds		29,386		—		—		29,386
Reverse repurchase agreements		—		10,000		—		10,000
Commercial paper		—		6,958		—		6,958
Corporate bonds		—		8,096		—		8,096
Total assets	$	72,631	$	25,054	$	—	$	97,685

Schedule of Change in the Fair Value of the Warrant Liability

The Company’s convertible preferred stock warrants were converted into common stock warrants upon the closing of an initial public offering of the Company’s common stock (“IPO”) in March 2019. The change in the fair value of the warrant liability for the three months ended March 31, 2019 is summarized below (in thousands):

Balance at December 31, 2018	$	313
Change in fair value of warrant liability		609
Net exercise of warrants		(133	)
Conversion of Series A preferred stock warrants to common    stock warrants upon the closing of the IPO		(789	)
Balance at March 31, 2019	$	—

Fair Value of Warrants Using Black-Scholes Option Pricing Model

The fair value of the warrants was determined using the Black-Scholes option pricing model and the following assumptions:

	March 31, 2019
Expected term (in years)		5.3
Expected volatility	43.9%
Risk-free interest rate	2.5%
Expected dividend yield	0%