Commitments and contingencies - Schedule of minimum lease payments (Detail) - USD ($) $ in Thousands	Jan. 31, 2020	Jan. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
2021	$ 2,648
2022	1,708
2023	568
Total capital lease payments	4,924
Less: Amounts representing interest	(504)
Total capital lease payments, net of interest	4,420
Less: Current portion	(2,324)	$ (1,869)
Total capital lease payments, net of interest and current portion	$ 2,096	$ 2,401

Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal through the balance sheet date.

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Amount of capital lease obligation due within one year or the normal operating cycle, if longer.

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Amount of minimum lease payments for capital leases.

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Amount of minimum lease payments for capital leases due in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount necessary to reduce net minimum lease payments to present value for capital leases.

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