Fair Value Measurements (Tables)

3 Months Ended

Apr. 30, 2019

Fair Value Disclosures [Abstract]

Schedule of Financial Instruments Measured at Fair Value on Recurring Basis

The following table presents information about our financial instruments that are measured at fair value on a recurring basis using the input categories further discussed in Note 1. “Summary of Business and Significant Accounting Policies” in the Notes to Consolidated Financial Statements in our Prospectus:

	April 30, 2019
	Fair Value		Level 1		Level 2		Level 3
	(in thousands)
Financial Assets:
Money market funds	$	202,605	$	202,605	$	—	$	—
Treasury bills		253,796		—		253,796		—
Cash equivalents		456,401		202,605		253,796		—
Corporate bonds		53,739		—		53,739		—
Agency bonds		21,458		—		21,458		—
U.S. government agency securities		32,192		—		32,192		—
Marketable securities		107,389		—		107,389		—
Certificate of deposit		200		—		200		—
Prepaid expenses and other current assets		200		—		200		—
Certificates of deposit		2,144		—		2,144		—
Other assets, non-current		2,144		—		2,144		—
Total financial assets	$	566,134	$	202,605	$	363,529	$	—

	January 31, 2019
	Fair Value		Level 1		Level 2		Level 3
	(in thousands)
Financial Assets:
Money market funds	$	78	$	78	$	—	$	—
Cash equivalents		78		78		—		—
Commercial paper		1,243		—		1,243		—
Corporate bonds		53,214		—		53,214		—
Agency bonds		32,604		—		32,604		—
U.S. government agency securities		24,017		—		24,017		—
Treasury bills		1,699		—		1,699		—
Marketable securities		112,777		—		112,777		—
Certificate of deposit		200		—		200		—
Prepaid expenses and other current assets		200		—		200		—
Certificates of deposit		2,144		—		2,144		—
Other assets, non-current		2,144		—		2,144		—
Total financial assets	$	115,199	$	78	$	115,121	$	—
Financial Liabilities:
Convertible promissory notes – derivative    liabilities	$	163	$	—	$	—	$	163
Other liabilities, non-current		163		—		—		163
Total financial liabilities	$	163	$	—	$	—	$	163

Summary of Changes in Fair Value of Financial Instruments

The following table sets forth a summary of the changes in the fair value of our Level 3 financial instruments as follows:

	Derivative Liabilities
	(in thousands)
Balance - January 31, 2019	$	163
Extinguishment of derivative liabilities from the convertible    promissory notes in connection with the IPO		(163	)
Balance - April 30, 2019	$	—