Fair Value Measurements - Summary of Changes in Fair Value of Financial Instruments (Details) - Fair Value, Inputs, Level 3 $ in Thousands	6 Months Ended
	Jul. 31, 2019 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 163
Ending Balance	0
Convertible Promissory Notes
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Extinguishment of derivative liabilities from the convertible promissory notes in connection with the IPO	$ (163)