Balance Sheet Components - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Jul. 31, 2019	Jan. 31, 2019
Balance Sheet Components [Abstract]
Accrued compensation and benefits	$ 30,339	$ 12,004
Accrued expenses	20,092	13,596
Operating lease liabilities, current	5,277
Sales and other tax liabilities	2,440	1,183
Liability for early exercise of common stock options	1,797	1,781
Other	4,641	3,692
Accrued expenses and other current liabilities	$ 64,586	$ 32,256