Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jul. 31, 2020	Jan. 31, 2020
Statement of Financial Position [Abstract]
Accumulated depreciation and amortization, property and equipment	$ 40,219	$ 35,551
Accumulated amortization, capitalized internal-use software	22,420	19,554
Accumulated amortization, intangible assets	$ 390	$ 271
Common stock, par value per share (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)	37,882,837	36,610,763
Common stock, shares outstanding (in shares)	37,882,837	36,610,763